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Annual Review of Fluid Mechanics top

► Formation and Evolution of Planetary Stagnant Lids and Crusts
    3 Jun, 2025

Earth is the only known planet with plate tectonics, which involves a mobile upper thermal boundary layer. Other terrestrial planets show a one-plate immobile lithosphere, or stagnant lid, that insulates and isolates their interior. Here, we first review the different types of lids that can develop on rocky and icy bodies. As they formed by accretion, involving high-energy impacts, terrestrial planets likely started hot and molten. We examine the process of lid initiation from a magma ocean stage and develop the equations for lid growth. We survey how lateral perturbations in lid and crust thickness can be amplified during their growth and finally discuss the possible processes at the origin of lid rupture and plate generation.

► Multiscale Modeling of Respiratory Transport Phenomena and Intersubject Variability
  22 Jan, 2025

Our understanding of respiratory flow phenomena has been consolidated over decades with the exploration of in vitro and in silico canonical models that underscore the multiscale fluid mechanics spanning the vast airway complex. In recent years, there has been growing recognition of the significant intersubject variability characterizing the human lung morphometry that modulates underlying canonical flows across subjects. Despite outstanding challenges in modeling and validation approaches, exemplified foremost in capturing chronic respiratory diseases, the field is swiftly moving toward hybrid in silico whole-lung simulations that combine various model classes to resolve airflow and aerosol transport spanning the entire respiratory tract over cumulative breathing cycles. In the years to come, the prospect of accessible, community-curated datasets, in conjunction with the use of machine learning tools, could pave the way for in silico population-based studies to uncover unrecognized trends at the population level and deliver new respiratory diagnostic and pulmonary drug delivery endpoints.

► Introduction
  22 Jan, 2025
► Vortex-Induced Vibration of Flexible Cylinders in Cross-Flow
  22 Jan, 2025

This review provides a comprehensive analysis of the literature on vortex-induced vibration (VIV) of flexible circular cylinders in cross-flow. It delves into the details of the underlying physics governing the VIV dynamics of cylinders characterized by low mass damping and high aspect ratio, subject to both uniform and shear flows. It compiles decades of experimental investigations, modeling efforts, and numerical simulations and describes the fundamental findings in the field. Key focal points include but are not limited to amplitude–frequency response behavior, the relationship between the distributed loading acting on the cylinder and the trajectories and the near wake structures around the cylinder, the existence of traveling waves, the identification of power-in/power-out regions, and the modal overlapping and mode competition phenomena.

► Instabilities and Mixing in Inertial Confinement Fusion
  22 Jan, 2025

By imploding fuel of hydrogen isotopes, inertial confinement fusion (ICF) aims to create conditions that mimic those in the Sun's core. This is fluid dynamics in an extreme regime, with the ultimate goal of making nuclear fusion a viable clean energy source. The fuel must be reliably and symmetrically compressed to temperatures exceeding 100 million degrees Celsius. After the best part of a century of research, the foremost fusion milestone was reached in 2021, when ICF became the first technology to achieve an igniting fusion fuel (thermonuclear instability), and then in 2022 scientific energy breakeven was attained. A key trade-off of the ICF platform is that greater fuel compression leads to higher burn efficiency, but at the expense of amplified Rayleigh–Taylor and Richtmyer–Meshkov instabilities and kinetic-energy-wasting asymmetries. In extreme cases, these three-dimensional instabilities can completely break up the implosion. Even in the highest-yielding 2022 scientific breakeven experiment, high-atomic-number (high-Z) contaminants were unintentionally injected into the fuel. Here we review the pivotal role that fluid dynamics plays in the construction of a stable implosion and the decades of improved understanding and isolated experiments that have contributed to fusion ignition.

► Naval Engineering Pioneer Raye J. Montague (1935–2018)
  22 Jan, 2025

Raye Jean Montague (1935–2018) was a computer programmer and self-taught engineer who was at the forefront of modernizing naval architecture and naval engineering through the use of computer-aided design. In this biographical review, she is referred to as Montague, the surname she had for much of her professional life. Since she was a working engineer rather than a scholar, she did not create a publication record by which her achievements can be easily tracked, but her name appears in committee memberships, conference and working group proceedings, and other such interstices of computer-aided ship design. This key contributor to computer-aided design and manufacturing and to naval engineering is well worth getting to know.

► Thermoacoustic Instability in Combustors
  22 Jan, 2025

Thermoacoustic instability is a flow instability that arises due to a two-way coupling between acoustic waves and unsteady heat release rate. It can cause damaging, large-amplitude oscillations in the combustors of gas turbines, aeroengines, rocket engines, etc., and the transition to decarbonized fuels is likely to introduce new thermoacoustic instability problems. With a focus on practical thermoacoustic instability problems, especially in gas turbine combustors, this review presents the common types of combustor and burner geometry used. It discusses the relevant flow physics underpinning their acoustic and unsteady flame behaviors, including how these differ across combustor and burner types. Computational tools for predicting thermoacoustic instability can be categorized into direct computational approaches, in which a single flow simulation resolves all of the most important length scales and timescales, and coupled/hybrid approaches, which couple separate computational treatments for the acoustic waves and flame, exploiting the large disparity in length scales associated with these. Examples of successful computational prediction of thermoacoustic instability in realistic combustors are given, along with outlooks for future research in this area.

► Rapidly Rotating Magnetohydrodynamics and the Geodynamo
  22 Jan, 2025

The problem of the geodynamo is simple to formulate (Why does the Earth possess a magnetic field?), yet it proves surprisingly hard to address. As with most geophysical flows, the fluid flow of molten iron in the Earth's core is strongly influenced by the Coriolis effect. Because the liquid is electrically conducting, it is also strongly influenced by the Lorentz force. The balance is unusual in that, whereas each of these effects considered separately tends to impede the flow, the magnetic field in the Earth's core relaxes the effect of the rapid rotation and allows the development of a large-scale flow in the core that in turn regenerates the field. This review covers some recent developments regarding the interplay between rotation and magnetic fields and how it affects the flow in the Earth's core.

► Asymmetries in Nominally Symmetric Flows
  22 Jan, 2025

Many flows that are expected to be symmetric are actually observed to be asymmetric. The appearance of asymmetry in the face of no particular cause is a widespread although underappreciated occurrence. This rather puzzling and sometimes frustrating phenomenon can occur in wide-angle diffusers, over the forebody of axisymmetric bodies at high angles of attack, in the wake downstream of streamlined as well as bluff bodies, and in the flow over three-dimensional bumps and ramps. We review some notable examples and highlight the extreme sensitivity of many such flows to small disturbances in the body geometry or the incoming flow. Some flows appear to be permanently asymmetric, while others are bistable on timescales that are orders of magnitude longer than any convective timescale. Convective or global instabilities can occur, bistability is common, and mode interactions become important when multiple similar but distinct timescales and length scales are present. Our understanding of these phenomena is still very limited, and further research is urgently required; asymmetries in otherwise symmetric flows can have serious real-world consequences on vehicle control and performance.

► Fluid Mechanics of the Dead Sea
  22 Jan, 2025

The environmental setting of the Dead Sea combines several aspects whose interplay creates flow phenomena and transport processes that cannot be observed anywhere else on Earth. As a terminal lake with a rapidly declining surface level, the Dead Sea has a salinity that is close to saturation, so that the buoyancy-driven flows common in lakes are coupled to precipitation and dissolution, and large amounts of salt are being deposited year-round. The Dead Sea is the only hypersaline lake deep enough to form a thermohaline stratification during the summer, which gives rise to descending supersaturated dissolved-salt fingers that precipitate halite particles. In contrast, during the winter the entire supersaturated, well-mixed water column produces halite. The rapid lake level decline of (1 m/year) exposes vast areas of newly formed beach every year, which exhibit deep incisions from streams. Taken together, these phenomena provide insight into the enigmatic salt giants observed in the Earth's geological record and offer lessons regarding the stability, erosion, and protection of arid coastlines under sea level change.

Computers & Fluids top

► Mean mesh adaptation for efficient CFD simulations with operating conditions variability
    

Publication date: 15 August 2025

Source: Computers & Fluids, Volume 298

Author(s): Hugo Dornier, Olivier P. Le Maître, Pietro M. Congedo, Itham Salah el Din, Julien Marty, Sébastien Bourasseau

► Adaptive fully implicit and thermodynamically consistent modeling of multiphase flow in porous media on three dimensional grids
    

Publication date: 15 August 2025

Source: Computers & Fluids, Volume 298

Author(s): Qiuyu Sheng, Haijian Yang, Huangxin Chen, Tianpei Cheng, Shuyu Sun

► A BDF2 characteristic-Galerkin isogeometric analysis for the miscible displacement of incompressible fluids in porous media
    

Publication date: 15 August 2025

Source: Computers & Fluids, Volume 298

Author(s): Ilham Asmouh, Abdelouahed Ouardghi

► Structure and dynamics of the blue whirl
    

Publication date: 15 August 2025

Source: Computers & Fluids, Volume 298

Author(s): E. Tarik Balci, Paul Anderson, Elaine S. Oran

► Exploring denoising diffusion models for compressible fluid field prediction
    

Publication date: 15 August 2025

Source: Computers & Fluids, Volume 298

Author(s): R. Abaidi, N.A. Adams

► A difference-free conservative phase-field Lattice Boltzmann method
    

Publication date: 15 August 2025

Source: Computers & Fluids, Volume 298

Author(s): Chunheng Zhao, Saumil Patel, Taehun Lee

► A distributed element roughness model for generalized surface morphologies
    

Publication date: 15 August 2025

Source: Computers & Fluids, Volume 298

Author(s): Samuel Altland, Vishal Wadhai, Shyam Nair, Xiang Yang, Robert Kunz, Stephen McClain

► Large airfoil models
    

Publication date: 15 August 2025

Source: Computers & Fluids, Volume 298

Author(s): Howon Lee, Aanchal Save, Pranay Seshadri, Juergen Rauleder

► Sharp Interface Capturing Godunov Method for Multi-Material Flow Simulations
    

Publication date: Available online 6 June 2025

Source: Computers & Fluids

Author(s): Igor Menshov, Pavel Zakharov, Rodion Muratov

► Editorial: Special Issue on “New Directions in Computational Fluid Dynamics”
    

Publication date: Available online 28 May 2025

Source: Computers & Fluids

Author(s): Rajesh Ranjan, Tirupathur N. Venkatesh, Joseph Mathew

International Journal of Computational Fluid Dynamics top

► Euler-Eulerian Multiphase Simulations of Micro-Bubble Drag Reduction With S-Gamma and AMUSIG Models
    3 Jun, 2025
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► Accelerated Selective Algebraic Multigrid Method for Fully-Coupled Incompressible Flow Solver
    8 May, 2025
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► Ensemble Transfer Learning for Rapid Fan Performance Prediction Across Configurations
    8 May, 2025
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► A Lagrangian RANS CFD-SPH Code for Turbulent Flows with Pollutant Transport and Applications to Outdoor/Indoor/Duct Air Quality
  11 Mar, 2025
Volume 38, Issue 5, June 2024, Page 339-376
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► On the Invalidity of the Extended Navier-Stokes Equations to Compute Rarefied Gas Flows in a Cylinder Array
    5 Mar, 2025
Volume 38, Issue 5, June 2024, Page 395-412
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► Flapping Dynamics and Stability of an Axially Functionally Graded Material Beam in Uniform Flow
    4 Feb, 2025
Volume 38, Issue 5, June 2024, Page 377-394
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► Erratum
  18 Aug, 2014
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International Journal for Numerical Methods in Fluids top

► Three‐Directional Orthogonality Preserving Method for Hyperbolic Grid Generation
    9 Jun, 2025
Three-Directional Orthogonality Preserving Method for Hyperbolic Grid Generation

We propose in this article a new three-directional orthogonality preserving method (TDOP) for hyperbolic grid generation. Compared with the traditional method that sacrifices the orthogonal constraint on the advancing front layer, TDOP derives new governing equations for hyperbolic grid generation that can take all orthogonal constraints into consideration. Results of application cases demonstrate that TDOP can generate computational grids with higher quality than the traditional method.


ABSTRACT

The hyperbolic grid generation method is widely used for generating computational grids. Because of conflicts arising from various grid constraints, the traditional hyperbolic grid generation method faces challenges in guaranteeing the fulfillment of all orthogonal constraints among three directions during the grid generation. A new three-directional orthogonality preserving method (TDOP) is introduced in the present work to enhance the orthogonality of the computational grid during the grid generation process. Unlike the traditional grid generation method, TDOP takes all three orthogonal constraints into consideration, establishes a function to quantify the overall grid orthogonality, and subsequently derives new governing equations for grid generation by solving a constrained optimization problem. Compared with the traditional method, TDOP exhibits enhanced control over the orthogonality among three directions, thereby enabling the generation of a computational grid with better orthogonality. Three application cases are employed to demonstrate the effectiveness and superiority of TDOP in hyperbolic grid generation. Results indicate that, compared with the traditional method, TDOP can effectively prevent the emergence of highly skewed grids and enables enhanced optimization of orthogonality in the advancing front layer. Consequently, TDOP can generate a computational grid with better orthogonality and higher quality than the traditional method.

► Higher Order Method Based on the Combination of Local Discontinuous Galerkin and Spectral Deferred Correction Method for the Rotating Navier–Stokes Equations
    6 Jun, 2025
Higher Order Method Based on the Combination of Local Discontinuous Galerkin and Spectral Deferred Correction Method for the Rotating Navier–Stokes Equations

In this article, A Higher order numerical algorithm based on LDG and SDC method for the rotating Navier–Stokes equations are presented. Moreover, the stability of the second-order fully discrete method is proved. Finally, the theoretical results and effectiveness are verified through numerical examples.


ABSTRACT

In this article, the spatial local discontinuous Galerkin (LDG) method and the temporal spectral deferred correction (SDC) method are combined to construct the higher-order approximating method for the unsteady rotating Navier–Stokes equations on the triangular mesh. First, the artificially compressible method is used to circumvent the incompressibility constraint, and the rotating Navier–Stokes equations are transformed into the artificially compressible rotating Navier–Stokes equations. Then, based on equal LDG interpolation and repeated temporal SDC, the higher-order fully discrete method is presented. Theoretically, the stability analysis of the second-order fully discrete method is provided, and it is shown that the time step τ$$ \tau $$ is stable within the upper bound constraints. Numerical examples are presented to demonstrate the effectiveness of the proposed method.

► An Extended HLLD Riemann Solver for the Numerical Simulation of Magneto‐Hydrodynamics
    6 Jun, 2025
An Extended HLLD Riemann Solver for the Numerical Simulation of Magneto-Hydrodynamics

Compared with the HLLD solver, the slow waves are allowed to persist inside the Riemann fan, so that the two Alfven waves are replaced by the two compound waves. The numerical tests showed that the extended HLLD solver has better performance for the capture of slow waves than the HLLD solver, and exhibits overall better accuracy in some situations where the slow waves exist.


ABSTRACT

By revisiting the derivation of multi-state HLL approximate Riemann solver for the ideal magneto-hydrodynamics, an extended HLLD Riemann solver is constructed based on the assumption that the normal velocity is constant over the Riemann fan, which is bounded by two fast waves, and separated by two compound waves and a middle contact wave. Compared with the HLLD solver, the slow waves are allowed to persist inside the Riemann fan, so that the two Alfvén waves are replaced by the two compound waves that are the merging product of the Alfvén and slow waves. Conseq uently, the corresponding wave speeds are chosen to be an interpolation between the Alfvén and slow waves for simplicity. The numerical tests showed that the extended HLLD solver (called HLLD-P) has better performance for the capture of slow waves than the HLLD solver, and exhibits overall better accuracy in some situations where the slow waves exist. However, the new solver does not capture the Alfvén wave as well as the HLLD solver once the estimated speeds of compound waves deviate from the Alfvén wave speeds. Overall, the HLLD-P solver is fully compatible with the HLLD solver as long as the compound waves degenerate to the Alfvén waves inside the Riemann fan. It is indicated that the HLLD-P solver can be used for the various applications of MHD simulation, especially for those cases where the slow waves are expected to be generated.

► An Extended Height‐Function Method for 3D VOF Simulations of Wetting Phenomena on Super‐Hydrophilic and Hydrophobic Surfaces
    3 Jun, 2025
An Extended Height-Function Method for 3D VOF Simulations of Wetting Phenomena on Super-Hydrophilic and Hydrophobic Surfaces

An extended height function method for 3D VOF simulations applicable to the wetting phenomena on super-hydrophilic and super-hydrophobic surfaces is proposed. By implementing specific treatments of contact line identification and height function construction, reflecting the contact angle boundary condition, the proposed method ensures the first- or second-order convergence of the curvature at the contact line for a wide range of contact angles. Additionally, droplet spreading driven by surface tension on solid walls can be reproduced.


ABSTRACT

An extended height-function (HF) method that can be consistently utilized for 3D volume of fluid (VOF) simulations of wetting phenomena on super-hydrophilic and super-hydrophobic surfaces, is proposed. First, the standard HF method is briefly explained. Then, 2D and 3D HF methods that reflect the contact angles reported so far are described, with their limitations discussed. Finally, specific treatments of contact line identification and HF construction reflecting the contact angle boundary condition, required to overcome such limitations, are presented in detail. Numerical tests for a sessile droplet reveal that the contact line identification and HF construction are conducted appropriately with respect to the imposed contact angles ranging from 15∘$$ 1{5}^{\circ } $$ to 165∘$$ 16{5}^{\circ } $$ in the proposed numerical scheme. Additionally, the present method shows approximately first- or second-order convergence of the curvature at the contact line for a wide range of contact angles. Moreover, simulations of droplet spreading driven by surface tension reveal that the proposed method can reasonably reproduce the behavior of a droplet reaching an equilibrium state defined by an imposed contact angle.

► Cavitation Implementation Algorithms Based on Pressure Projection Method for Incompressible Flows With Three‐Phase Interactions
    3 Jun, 2025
Cavitation Implementation Algorithms Based on Pressure Projection Method for Incompressible Flows With Three-Phase Interactions

A cavitation implementation algorithm is developed using a pressure-based method for incompressible flows with three-phase interactions, which involve high Reynolds number multi-phase turbulent flows interacting with moving bodies of complex geometries.


ABSTRACT

In the present study, a cavitation implementation algorithm is developed using a pressure-based method for incompressible flows with three-phase interactions. Central to this implementation algorithm is the treatment of the velocity jump due to the phase change, which is included in both the cavitation transport and pressure equations. The velocity jump, as a function of the phase change rate, is added as a source term to the pressure Poisson equation. A non-conservative form of the vapor transport equation is derived, and the velocity divergence is replaced by a term related to the mass phase change rate. An algorithm for the three-phase (air, water, and vapor) interactions is also developed. The VOF method is modified and used to identify the ‘dry’ (air) phase and the ‘wet’ (water/vapor mixture) phase, since the cavitation can only occur inside the water phase. The liquid volume fraction is used to distinguish water and vapor phases. The numerical results of the 2D NACA66MOD and 3D Delft Twist 11 hydrofoils show good agreement with the experimental measurement. The forced unsteady cavitation flows are investigated using a pitching foil with the results compared with the experimental observations. Air–water interface effect on the cavitation is investigated using the NACA66MOD hydrofoil. The code is applied to simulate a surface piercing super cavitating hydrofoil with both ventilation and cavitation involved.

► Issue Information
    3 Jun, 2025
International Journal for Numerical Methods in Fluids, Volume 97, Issue 7, July 2025.
► SDF‐Guided Point Cloud Generation Framework for Mesh‐Free CFD
    3 Jun, 2025
SDF-Guided Point Cloud Generation Framework for Mesh-Free CFD

This paper presents different methods for generating clouds of points around objects for use with meshless methods in computational fluid dynamics. This image shows the cloud generated around the original ROBIN body.


ABSTRACT

Meshing is a bottleneck of CFD workflows, especially when complex geometries are considered. Mesh-free methods could be a promising solution, but the lack of high-quality point cloud generation methods for boundary layers has hindered their popularity and applications. This work presents a novel point cloud generation framework for near- and off-body regions. The novelty of the method is the introduction of the Signed Distance Function (SDF) to guide advancing point layers in the near-body region. Insertion/removal mechanisms of points, collocation search approach, and point cloud quality metrics were also proposed. These ensure high-quality boundary layer resolution in the near-body region, regardless of the complexity and topology of the geometry. For the off-body region, Cartesian points are employed for smooth and adaptive point distributions. Compared to conventional advancing front point generation, the proposed method ensures surface-norm point distributions with consistent layer structures, which are critical for boundary layer resolution. Compared to the strand mesh generation, the current method presents much greater flexibility with few restrictions on inter-layer connections. The proposed approach is tested for various 2D and 3D benchmark geometries, along with mesh-free modeling results using the generated point clouds. The results demonstrate an important step towards a fully automated, adaptive, and mesh-free CFD workflow for complex engineering applications.

► Local and Parallel Mixed‐Precision Finite Element Methods for the Time‐Dependent Incompressible Flows
    3 Jun, 2025
Local and Parallel Mixed-Precision Finite Element Methods for the Time-Dependent Incompressible Flows

The approximational solution is decomposed into large and small eddy components. The high-precision solver is used to obtain the large eddy components and the low-precision solver is used to obtain the small eddy components since that the small eddy components carry a little part of the total energy. Numerical tests present the efficiency of the mixed-precision method.


ABSTRACT

In this article, a local and parallel mixed-precision finite element method is applied for solving the time-dependent incompressible flows. We decompose the solution into the large eddy components and small eddy components based on two-grid method. The analysis shows that the small eddy components carry little part of the total energy compared with the large eddy components. In view of this character, we first obtain the large eddy components by solving the standard nonlinear equation using the high-precision solvers globally in the coarse mesh space, then get the small eddy components by solving a series of local linearized residual equation using the low-precision solvers locally and parallel based on the partition of unity. The performance advantages of the mixed-precision methods are tested with respect to speedups over a high-precision implementation in time and less storage requirements in space.

► Comparison of Numerical Methods for Geometric Warpage Compensation
  29 May, 2025
Comparison of Numerical Methods for Geometric Warpage Compensation

In the process of injection molding, shrinkage and warpage can lead to variations in the size and shape of produced parts compared to the cavity shape. Our research evaluated different algorithms for warpage compensation in injection molding. Our main finding was that the reverse geometry method consistently outperformed other tested algorithms on all geometries and is the most straightforward to implement.


ABSTRACT

In injection molding processes, shrinkage and warpage cause deviations in the size and shape of produced parts compared to the cavity shape. While shrinkage is due to the change of material density during solidification, warpage is caused by uneven cooling and internal stresses within the part. One approach to mitigate these effects is by adjusting the cavity shape to anticipate the deformation. While finding the optimal cavity shape is often experience-based in practice, numerical design optimization can greatly assist in this process. In this study, we evaluate various numerical algorithms from existing literature to identify the optimal cavity shape. Each method is briefly outlined regarding how it adapts the geometry, and we discuss their respective strengths and weaknesses for different scenarios. We conduct comparisons using 3D geometries of varying complexity. Our findings demonstrate that, for geometric warpage compensation, the node-based reverse geometry method yields the least warpage and is computationally cost-effective. Furthermore, it is straightforward to implement and consistently performs well across different geometries.

► Extrapolation Boundary Conditions for 2‐D Smoothed Particle Hydrodynamics
  22 May, 2025
Extrapolation Boundary Conditions for 2-D Smoothed Particle Hydrodynamics

This paper introduces novel inflow, outflow, and wall boundaries for the WCSPH method. Utilising innovative concepts from finite volume methods, fluid properties of sequential dynamic particles with varying distances to boundaries are extrapolated to ghost and wall particles using first-order Taylor series expansion. Unlike existing SPH boundary conditions, no mirror points are required, improving computational efficiency. Additionally, no pressure fluctuations or acoustic noise are observed for both open and wall boundaries, demonstrating the method's effectiveness.


ABSTRACT

This paper presents a new robust treatment for smoothed particle hydrodynamics (SPH) open (inflow/outflow) and solid boundary conditions, avoiding the unphysical fluctuations and numerical noise present in existing techniques. By novel use of concepts from finite volume methods, the fluid properties from sequential dynamic particles with different normal distances to the boundaries are extrapolated to ghost particles. No so-called mirror points are required, making the method computationally efficient and easy to implement. The new methodology is validated through a series of progressively challenging test cases. The effectiveness of the wall and inflow-outflow boundaries is evaluated for 2-D Poiseuille laminar flow. The performance of the wall boundary for complex geometries is demonstrated using a hydrostatic tank with a triangular wedge, followed by a conventional 2-D dam-break problem to capture impact pressures. A range of challenging vertical inflows rarely explored using SPH, with varying efflux velocities, demonstrate highly accurate performance of the boundary treatment, with results compared to STAR-CCM+. Finally, the robust performance is demonstrated for flow past circular and square cylinders over a range of Reynolds numbers, showing excellent results compared to reference results.

Journal of Computational Physics top

► A framework for learning symbolic turbulence models from indirect observation data via neural networks and feature importance analysis
    

Publication date: 15 September 2025

Source: Journal of Computational Physics, Volume 537

Author(s): Chutian Wu, Xin-Lei Zhang, Duo Xu, Guowei He

► An explicit, energy-conserving particle-in-cell scheme
    

Publication date: 15 September 2025

Source: Journal of Computational Physics, Volume 537

Author(s): Lee F. Ricketson, Jingwei Hu

► A structure-preserving discontinuous Galerkin scheme for the Cahn-Hilliard equation including time adaptivity
    

Publication date: 15 September 2025

Source: Journal of Computational Physics, Volume 537

Author(s): Golo A. Wimmer, Ben S. Southworth, Qi Tang

► An efficient implicit scheme for the multimaterial Euler equations in Lagrangian coordinates
    

Publication date: 15 September 2025

Source: Journal of Computational Physics, Volume 537

Author(s): Simone Chiocchetti, Giovanni Russo

► A bound-preserving Runge–Kutta discontinuous Galerkin method with compact stencils for hyperbolic conservation laws
    

Publication date: 15 September 2025

Source: Journal of Computational Physics, Volume 537

Author(s): Chen Liu, Zheng Sun, Xiangxiong Zhang

► A coupled PFEM-DEM model for fluid-granular flows with free surface dynamics applied to landslides
    

Publication date: 15 September 2025

Source: Journal of Computational Physics, Volume 537

Author(s): Thomas Leyssens, Michel Henry, Jonathan Lambrechts, Vincent Legat, Jean-François Remacle

► Well-balanced discontinuous Galerkin method with flux globalization for rotating shallow water equations
    

Publication date: 15 September 2025

Source: Journal of Computational Physics, Volume 537

Author(s): Jiahui Zhang, Yinhua Xia, Yan Xu

► Predicting nonlinear-flow regions in highly heterogeneous porous media using adaptive constitutive laws and neural networks
    

Publication date: 15 September 2025

Source: Journal of Computational Physics, Volume 537

Author(s): Chiara Giovannini, Alessio Fumagalli, Francesco Saverio Patacchini

► Adjoint shape optimization from the continuum to free-molecular gas flows
    

Publication date: 15 September 2025

Source: Journal of Computational Physics, Volume 537

Author(s): Ruifeng Yuan, Lei Wu

► A micro-macro decomposition-based asymptotic-preserving random feature method for multiscale radiative transfer equations
    

Publication date: 15 September 2025

Source: Journal of Computational Physics, Volume 537

Author(s): Jingrun Chen, Zheng Ma, Keke Wu

Journal of Turbulence top

► Effect of impingement distance on flow characteristics and impingement pressure of an acoustically excited jet impingement
  28 May, 2025
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► Modelling of turbulent shear stress in vertical bubbly flows at low void fractions and low flow velocities
  26 May, 2025
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► On the physical dimension of the turbulent sublayer at the turbulent/non-turbulent interface
    7 May, 2025
Volume 26, Issue 5, May 2025, Page 174-195
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► Many wrong models approach to localise an odour source in turbulence with static sensors
  18 Apr, 2025
Volume 26, Issue 5, May 2025, Page 153-173
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► Spectrum correction in Ekman-Navier-Stokes turbulence
  15 Apr, 2025
Volume 26, Issue 5, May 2025, Page 143-152
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Physics of Fluids top

► A sharp interface immersed edge-based smoothed finite element method with extended fictitious domain scheme
  17 Apr, 2023
Physics of Fluids, Volume 35, Issue 4, April 2023.
This paper proposes a versatile and robust immersed edge-based smoothed finite element method with the mass conservation algorithm (IESFEM/Mass) to solve partitioned fluid–structure interaction (FSI). A gradient smoothing technique was used to solve the system governing equations, which can improve the calculated capability of the linear triangular elements in two phases. Based on the quadratic sharp interface representation of immersed boundary, an extended fictitious domain constructed by a least squares method approximately corrected the residual flux error. The compatibility for boundary conditions on moving interfaces was satisfied, thus eliminating spurious oscillations. The results from all numerical examples were consistent with those from the existing experiments and published numerical solutions. Furthermore, the present divergence-free vector field had a faster-converged rate in the flow velocity, pressure, and FSI force. Even if in distorted meshes, the proposed algorithm maintained a stable accuracy improvement. The aerodynamics of one- and two-winged flapping motions in insect flight has been investigated through the IESFEM/Mass. It can be seen that the wing–wake interaction mechanism is a vital factor affecting the lift. The applicability of the present method in the biological FSI scenario was also well-demonstrated.
► Enhanced and reduced solute transport and flow strength in salt finger convection in porous media
  17 Apr, 2023
Physics of Fluids, Volume 35, Issue 4, April 2023.
We report a pore-scale numerical study of salt finger convection in porous media, with a focus on the influence of the porosity in the non-Darcy regime, which has received little attention in previous research. The numerical model is based on the lattice Boltzmann method with a multiple-relaxation-time scheme and employs an immersed boundary method to describe the fluid–solid interaction. The simulations are conducted in a two-dimensional, horizontally periodic domain with an aspect ratio of 4, and the porosity [math] is varied from 0.7 to 1, while the solute Rayleigh number [math] ranges from [math] to [math]. Our results show that, for all explored [math], solute transport first enhances unexpectedly with decreasing [math] and then decreases when [math] is smaller than a [math]-dependent value. On the other hand, while the flow strength decreases significantly as [math] decreases at low [math], it varies weakly with decreasing [math] at high [math] and even increases counterintuitively for some porosities at moderate [math]. Detailed analysis of the salinity and velocity fields reveals that the fingered structures are blocked by the porous structure and can even be destroyed when their widths are larger than the pore scale, but become more ordered and coherent with the presence of porous media. This combination of opposing effects explains the complex porosity dependencies of solute transport and flow strength. The influence of porous structure arrangement is also examined, with stronger effects observed for smaller [math] and higher [math]. These findings have important implications for passive control of mass/solute transport in engineering applications.
► On the instability of the magnetohydrodynamic pipe flow subject to a transverse magnetic field
  17 Apr, 2023
Physics of Fluids, Volume 35, Issue 4, April 2023.
The linear stability of a fully developed liquid–metal magnetohydrodynamic pipe flow subject to a transverse magnetic field is studied numerically. Because of the lack of axial symmetry in the mean velocity profile, we need to perform a BiGlobal stability analysis. For that purpose, we develop a two-dimensional complex eigenvalue solver relying on a Chebyshev–Fourier collocation method in physical space. By performing an extensive parametric study, we show that in contrast to the Hagen–Poiseuille flow known to be linearly stable for all Reynolds numbers, the magnetohydrodynamic pipe flow with transverse magnetic field is unstable to three-dimensional disturbances at sufficiently high values of the Hartmann number and wall conductance ratio. The instability observed in this regime is attributed to the presence of velocity overspeed in the so-called Roberts layers and the corresponding inflection points in the mean velocity profile. The nature and characteristics of the most unstable modes are investigated, and we show that they vary significantly depending on the wall conductance ratio. A major result of this paper is that the global critical Reynolds number for the magnetohydrodynamic pipe flow with transverse magnetic field is Re = 45 230, and it occurs for a perfectly conducting pipe wall and the Hartmann number Ha = 19.7.
► The turbulence development at its initial stage: A scenario based on the idea of vortices decay
  17 Apr, 2023
Physics of Fluids, Volume 35, Issue 4, April 2023.
In this paper, a model of the development of a quantum turbulence in its initial stage is proposed. The origin of the turbulence in the suggested model is the decay of vortex loops with an internal structure. We consider the initial stage of this process, before an equilibrium state is established. As result of our study, the density matrix of developing turbulent flow is calculated. The quantization scheme of the classical vortex rings system is based on the approach proposed by the author earlier.
► Interstage difference and deterministic decomposition of internal unsteady flow in a five-stage centrifugal pump as turbine
  17 Apr, 2023
Physics of Fluids, Volume 35, Issue 4, April 2023.
A five-stage centrifugal pump is utilized to investigate the interstage flow characteristics of the multistage centrifugal pump as turbine (PAT). The simulation results of performance are verified by comparing with the experimental results. Owing to the distinct structural attributes, significant differences in flow occur between the first stage and the other stages of the multistage PAT. To enhance the understanding of these disparities and explore their repercussions, this study focuses on analyzing the flow within the impellers in the first and second stages by a deterministic analysis. The main conclusions are as follows: The discrepancies in the inflow conditions are the major reason for the dissimilarities in the flow of impellers between stages. The impact loss generated by the misalignment between the positive guide vane outlet angle and the impeller inlet angle leads to flow deviation between impeller passages and affects the internal flow pattern. The unsteadiness under low flow rates is mostly produced by the spatial gradient of the blade-to-blade nonuniformities, which is relevant to the relative position between blades and the positive guide vanes. At high flow rates, especially in the second-stage impeller, the pure unsteady term is the primary cause of flow unsteadiness as a result of the flow separation induced by interactions between the blades and the positive guide vanes. This study can provide some references for the practical operation and performance optimization of the multistage PATs in the future.
► Effect of gravity on phase transition for liquid–gas simulations
  17 Apr, 2023
Physics of Fluids, Volume 35, Issue 4, April 2023.
Direct simulations of phase-change and phase-ordering phenomena are becoming more common. Recently, qualitative simulations of boiling phenomena have been undertaken by a large number of research groups. One seldom discussed limitation is that large values of gravitational forcing are required to simulate the detachment and rise of bubbles formed at the bottom surface. The forces are typically so large that neglecting the effects of varying pressure in the system becomes questionable. In this paper, we examine the effect of large pressure variations induced by gravity using pseudopotential lattice Boltzmann simulations. These pressure variations lead to height dependent conditions for phase coexistence and nucleation of either gas or liquid domains. Because these effects have not previously been studied in the context of these simulation methods, we focus here on the phase stability in a one-dimensional system, rather than the additional complexity of bubble or droplet dynamics. Even in this simple case, we find that the different forms of gravitational forces employed in the literature lead to qualitatively different phenomena, leading to the conclusion that the effects of gravity induced pressure variations on phase-change phenomena should be very carefully considered when trying to advance boiling and cavitation as well as liquefaction simulations to become quantitative tools.
► Entrapment and mobilization dynamics during the flow of viscoelastic fluids in natural porous media: A micro-scale experimental investigation
  17 Apr, 2023
Physics of Fluids, Volume 35, Issue 4, April 2023.
Capillary desaturation process was investigated as a function of wetting phase rheological signatures during the injection of Newtonian and non-Newtonian fluids. Two sets of two-phase imbibition flow experiments were conducted on a water-wet sandstone core sample using brine and viscoelastic polymer solutions. During the experiments, a high-resolution micro-computed tomography scanner was employed to directly map pore-level fluid occupancies within the pore space. The results of the experiments revealed that at a given capillary number, the viscoelastic polymer was more efficient than the brine in recovering the non-wetting oil phase. At low capillary numbers, this is attributed to the improved accessibility of the viscoelastic polymer solution to the entrance of pore elements, which suppressed snap-off events and allowed more piston-like and cooperative pore-body filling events to contribute to oil displacement. For intermediate capillary numbers, the onset of elastic turbulence caused substantial desaturation, while at high capillary numbers, the superimposed effects of higher viscous and elastic forces further improved the mobilization of the trapped oil ganglia by the viscoelastic polymer. In the waterflood, however, the mobilization of oil globules was the governing recovery mechanism, and the desaturation process commenced only when the capillary number reached a threshold value. These observations were corroborated with the pore-level fluid occupancy maps produced for the brine and viscoelastic polymer solutions during the experiments. Furthermore, at the intermediate and high capillary numbers, the force balance and pore-fluid occupancies suggested different flow regimes for the non-Newtonian viscoelastic polymer. These regions are categorized in this study as elastic-capillary- and viscoelastic-dominated flow regimes, different from viscous-capillary flow conditions that are dominant during the flow of Newtonian fluids. Moreover, we have identified novel previously unreported pore-scale displacement events that take place during the flow of viscoelastic fluids in a natural heterogeneous porous medium. These events, including coalescence, fragmentation, and re-entrapment of oil ganglia, occurred before the threshold of oil mobilization was reached under the elastic-capillary-dominated flow regime. In addition, we present evidence for lubrication effects at the pore level due to the elastic properties of the polymer solution. Furthermore, a comparison of capillary desaturation curves generated for the Newtonian brine and non-Newtonian viscoelastic polymer revealed that the desaturation process was more significant for the viscoelastic polymer than for the brine. Finally, the analysis of trapped oil clusters showed that the ganglion size distribution depends on both the capillary number and the rheological properties of fluids.
► Impact of wettability on interface deformation and droplet breakup in microcapillaries
  17 Apr, 2023
Physics of Fluids, Volume 35, Issue 4, April 2023.
The objective of this research paper is to relate the influence of dynamic wetting in a liquid/liquid/solid system to the breakup of emulsion droplets in capillaries. Therefore, modeling and simulation of liquid/liquid flow through a capillary constriction have been performed with varying dynamic contact angles from highly hydrophilic to highly hydrophobic. Advanced advection schemes with geometric interface reconstruction (isoAdvector) are incorporated for high interface advection accuracy. A sharp surface tension force model is used to reduce spurious currents originating from the numerical treatment and geometric reconstruction of the surface curvature at the interface. Stress singularities from the boundary condition at the three-phase contact line are removed by applying a Navier-slip boundary condition. The simulation results illustrate the strong dependency of the wettability and the contact line and interface deformation.
► Drag increase and turbulence augmentation in two-way coupled particle-laden wall-bounded flows
  17 Apr, 2023
Physics of Fluids, Volume 35, Issue 4, April 2023.
The exact regularized point particle method is used to characterize the turbulence modulation in two-way momentum-coupled direct numerical simulations of a turbulent pipe flow. The turbulence modification is parametrized by the particle Stokes number, the mass loading, and the particle-to-fluid density ratio. The data show that in the wide region of the parameter space addressed in the present paper, the overall friction drag is either increased or unaltered by the particles with respect to the uncoupled case. In the cases where the wall friction is enhanced, the fluid velocity fluctuations show a substantial modification in the viscous sub-layer and in the buffer layer. These effects are associated with a modified turbulent momentum flux toward the wall. The particles suppress the turbulent fluctuations in the buffer region and concurrently provide extra stress in the viscous sub-layer. The sum of the turbulent stress and the extra stress is larger than the Newtonian turbulent stress, thus explaining the drag increase. The non-trivial turbulence/particles interaction turns out in a clear alteration of the near-wall flow structures. The streamwise velocity streaks lose their spatial coherence when two-way coupling effects are predominant. This is associated with a shift of the streamwise vortices toward the center of the pipe and with the concurrent presence of small-scale and relatively more intense vortical structures near the wall.
► Partial and complete wetting of thin films with dynamic contact angle
  17 Apr, 2023
Physics of Fluids, Volume 35, Issue 4, April 2023.
The wetting of thin films depends critically on the sign of the spreading coefficient [math]. We discuss the cases S < 0, S = 0, and S > 0 for transient models with contact line dissipation and find that the use of a dynamic contact angle solves problems for S > 0 that models might otherwise have. For initial data with a non-zero slope and S > 0, we show that there exists a finite time [math] at which the contact angle of the thin film goes to zero. Then, a molecular precursor emerges from the thin film and moves outward at a constant velocity.

Theoretical and Computational Fluid Dynamics top

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Abstract Graphical abstract
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