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The Synthetik Applied Technologies team is excited to announce the release of blastFoam v3.0, the latest update to our free and open-source CFD airblast code for modeling high-explosive detonation.

Given the disruption to our planned software release schedule, and our growing user community who have used these extraordinary times to pick-up and start using the software, we’ve decided to advance our planned release date. We’re excited to announce our most significant release to date, blastFoam v3.0.

blastFoam now includes thirteen equations of state that allow modeling of diverse materials under extreme conditions, with consideration of phenomenologies such as excitation, dissociation and ionization of nitrogen and oxygen in air at higher energies and temperatures, afterburn, and sympathetic detonation.

We have introduced several different approaches to model detonation within explosive materials which transition from unreacted energetics to detonation products, including pressure-based activation models with multi-step Arrhenius reaction rates, and simple, yet practical models based on empirically derived detonation velocities. Users can also specify instantaneous activation.

blastFoam allows phenomena such as size effect (decrease of the detonation velocity with decreasing charge radius), and detonation front curvature (induced by edge lag of the front as energy is lost to the exterior of the charge) to be accurately captured. These additions greatly enhance timing accuracy and load characterization, especially for near-contact explosive scenarios. Options for modeling afterburn (i.e., under-oxygenated explosives continuing to burn after detonation) are also included using the Miller extension, constant, and linear rate models.

blastFoam extends OpenFOAM’s base AMR library, and includes the ability to perform 2D and 3D adaptive mesh refinement (AMR). The refinement criteria can be based on density gradient, change across faces (delta), or Lohner’s method (2nd derivative of a field) to determine what cell should be refined or unrefined. Additionally, options for mesh unrefinement/relaxation/coarsening have been added, and this is useful for keeping cell counts relatively constant during a calculation while still capturing key features (e.g. shocks) with high accuracy. This allows blastFoam to solve engineering-scale simulations at an affordable computational cost.

blastFoam extends OpenFOAM by adding dynamic load rebalancing for adaptive grids, and now includes a working solution for 2D and experimental support for 3D calculations. Essentially, at a predetermined timestep interval the domain is rebalanced so that the cell count per CPU is more evenly distributed. This mitigates potential memory issues such as crashing and slow-down related to overloading CPUs that are operating on zones of high refinement.

Turbulence and radiation models have been integrated, allowing blastFoam users to leverage the extensive OpenFOAM libraries and apply them to their simulations, and a new fluid model structure (fluidThermo class), that extends OpenFOAM’s standard thermo classes has been added, and provides thermodynamically consistent solutions for more accurate temperature calculations.

New functionObjects have been added to improve usability, including the ability to calculate peak overpressure and impulse for each cell in the domain, as well as blastToVTK, a utility to view time series mesh surface outputs in ParaView.

Additional validation and tutorial cases are also provided to demonstrate and showcase the new functionality and capabilities of blastFoam v3.0.

Synthetik Applied Technologies: https://www.synthetik-technologies.com/

Free online blastFoam Workshop | May 13, 2020: https://www.eventbrite.com/e/blastfoam-workshop-tickets-100310659884

blastFoam is available for free download here: https://github.com/synthetik-technologies/blastfoam