[Marala]

Hi!

I'm getting the following error in SU2 when I run my code:

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Parsing config file for zone 0

----------------- Physical Case Definition ( Zone 0 ) -------------------
Compressible RANS equations.
Turbulence model: Menter's SST
Hybrid RANS/LES: Delayed Detached Eddy Simulation (DDES) with Standard SGS
Mach number: 0.729.
Angle of attack (AoA): 2.31 deg, and angle of sideslip (AoS): 0 deg.
Reynolds number: 6.5e+006. Reference length 1.
No restart solution, use the values at infinity (freestream).
Dimensional simulation.
The reference area is 1 m^2.
The semi-span will be computed using the max y(3D) value.
The reference length is 1 m.
Reference origin for moment evaluation is (0.25, 0, 0).
Surface(s) where the force coefficients are evaluated: airfoil.

Surface(s) where the objective function is evaluated: airfoil.
Surface(s) plotted in the output file: airfoil.
Surface(s) to be analyzed in detail: airfoil.
Surface(s) affected by the design variables: airfoil.
Input mesh file name: V2.su2

--------------- Space Numerical Integration ( Zone 0 ) ------------------
Roe (with entropy fix = 0) solver for the flow inviscid terms.
Roe with DDES's FD low-dissipation function.
Second order integration in space, with slope limiter.
Venkatakrishnan slope-limiting method, with constant: 0.05.
The reference element size is: 1.
Scalar upwind solver for the turbulence model.
First order integration in space.
Average of gradients with correction (viscous flow terms).
Average of gradients with correction (viscous turbulence terms).
Gradient for upwind reconstruction: Green-Gauss.
Gradient for viscous and source terms: Green-Gauss.

--------------- Time Numerical Integration  ( Zone 0 ) ------------------
Local time stepping (steady state simulation).
Euler implicit method for the flow equations.
FGMRES is used for solving the linear system.
Using a ILU(0) preconditioning.
Convergence criteria of the linear solver: 1e-006.
Max number of linear iterations: 5.
No CFL adaptation.
Courant-Friedrichs-Lewy number:       15
Euler implicit time integration for the turbulence model.

------------------ Convergence Criteria  ( Zone 0 ) ---------------------
Maximum number of solver subiterations: 9999.
Begin convergence monitoring at iteration 10.
Residual minimum value: 1e-8.
Cauchy series min. value: 1e-010.
Number of Cauchy elements: 100.
Begin windowed time average at iteration 0.
Begin time convergence monitoring at iteration 0.
Time cauchy series min. value: 0.001.
Number of Cauchy elements: 10.

-------------------- Output Information ( Zone 0 ) ----------------------
Writing solution files every 10 iterations.
Writing the convergence history file every 1 inner iterations.
Writing the screen convergence history every 1 inner iterations.
The tabular file format is Tecplot (.dat).
Convergence history file name: history.
Forces breakdown file name: forces_breakdown.dat.
Surface file name: surface_flow.
Volume file name: flow.
Restart file name: restart_flow.dat.

------------- Config File Boundary Information ( Zone 0 ) ---------------
+-----------------------------------------------------------------------+
|                        Marker Type|                        Marker Name|
+-----------------------------------------------------------------------+
|                         Euler wall|                            airfoil|
+-----------------------------------------------------------------------+
|                          Far-field|                           farfield|
+-----------------------------------------------------------------------+

-------------------- Output Preprocessing ( Zone 0 ) --------------------
Screen output fields: INNER_ITER, RMS_DENSITY, RMS_MOMENTUM-X, RMS_MOMENTUM-Y, RMS_ENERGY
History output group(s): ITER, RMS_RES
Convergence field(s): DRAG
Ignoring Time Convergence Field(s): TAVG_DRAG TAVG_LIFT
Warning: No (valid) fields chosen for time convergence monitoring. Time convergence monitoring inactive.
Volume output fields: COORDINATES, SOLUTION, PRIMITIVE

------------------- Geometry Preprocessing ( Zone 0 ) -------------------
Two dimensional problem.
121992 grid points.
121210 volume elements.
2 surface markers.
782 boundary elements in index 0 (Marker = airfoil).
782 boundary elements in index 1 (Marker = farfield).
121210 quadrilaterals.
Setting point connectivity.
Renumbering points (Reverse Cuthill McKee Ordering).
Recomputing point connectivity.
Setting element connectivity.
Checking the numerical grid orientation.
Identifying edges and vertices.
Computing centers of gravity.
Setting the control volume structure.
Area of the computational grid: 0.
Searching for the closest normal neighbors to the surfaces.
Storing a mapping from global to local point index.
Compute the surface curvature.
Max K: 5.13859e-014. Mean K: 6.74669e-017. Standard deviation K: 1.31246e-015.
Checking for periodicity.
Computing mesh quality statistics for the dual control volumes.


Error in "virtual void CPhysicalGeometry::ComputeMeshQualityStatistics(CConfig*)":
-------------------------------------------------------------------------
Zero-area CV face found for point 121600.
------------------------------ Error Exit -------------------------------

As you can see it's a 2D problem of an airfoil in transonic flow, I created a mesh in Pointwise, of which I added three pictures: 1 is zoomed in to the airfoil, 1 is zoomed in on the error location and the last one shows the whole domain. I indicated to location of the point that's mentioned in the error with a red arrow on the last two. The mesh is structured, and I get the same error whether I export in the .su2 or .cgns format

When I examine the quality of the mesh in Pointwise all seems well, and the location of the error also looks completely normal. Rebuilding the mesh from scratch did not help either. So I'm not sure whether the mistakes originates in Pointwise or in SU2 at the moment (so sorry if this is the wrong place to post this question).

When I google the error I can't find any similar problems.

PointwiseMesh.png

PointwiseMeshZoomedIn.png

PointwiseMeshZoomedInError.png

Does anybody have experience with the error, or know how to better interpret it? The way I interpret the error at the moment I'd expect an element with an area of 0 at the indicated point, but this is clearly not the case. Is this the right interpretation?

The post becomes too long if I add my .cfg file as well (and the forum does not let me upload .cfg or .txt files), if you need any information from that please tell me, then I'll try and upload it another way.

Thanks a lot!

[Marala]

I found it! It turned out to be quite simple, I finally got it when I saw "Area of the computational grid: 0" in the output.
When you export a grid from pointwise, you have to make sure it's in the XY plane, mine was in the XZ. The point it indicates is simply the first one it checks I suppose.

Rotating my mesh fixed the problem

[monika_1387]

Hello, You are running HYBRID RANSLES ? So please let me know if you can help or SU2 team can help.

How you defined these 2 zones in .cfg? Or its default identified by SA-EDDES ? Or we need to make whole new grid with 2 defined zones?

Thank you in advance for help!

[ari003]

Originally Posted by Marala

I found it! It turned out to be quite simple, I finally got it when I saw "Area of the computational grid: 0" in the output.
When you export a grid from pointwise, you have to make sure it's in the XY plane, mine was in the XZ. The point it indicates is simply the first one it checks I suppose.

Rotating my mesh fixed the problem

Hi Marala, I m also facing the same problem. And it is probably because the Control Volume somewhere is zero. I checked the geometry and it is perfectly in x-y plane, remeshed with more refined cell but no improvement. Do you know any other reason to troubleshoot this problem?

Note:- When I remeshed, the CV point with 0 value is different from the previous coarse mesh.

[jdp810]

Have you checked that pointwise is set to 2D instead of 3D? maybe if it is in 3D it may export a 3D mesh in the XY plane, therefore your CV is empty?

[ari003]

Originally Posted by jdp810

Have you checked that pointwise is set to 2D instead of 3D? maybe if it is in 3D it may export a 3D mesh in the XY plane, therefore your CV is empty?

Thanks for your response Jose but I'm using GMSH for mesh generation.
The problem statement is as :-
I m using GMSH for mesh generation and the solver is SU2. I dont know how but when I'm using the transfinite curve option on the 2D curve of the airfoil the solver SU2 is giving me an error with

Zero-area CV face found for point 343.

When I remove the transfinite curve option the error disappears. I'm trying to get a refined unstructured mesh around my airfoil so that my y+ falls into the viscous sublayer region.
Is there any way to troubleshoot this problem?

[Mohsin1]

Originally Posted by ari003

Thanks for your response Jose but I'm using GMSH for mesh generation.
The problem statement is as :-
I m using GMSH for mesh generation and the solver is SU2. I dont know how but when I'm using the transfinite curve option on the 2D curve of the airfoil the solver SU2 is giving me an error with

When I remove the transfinite curve option the error disappears. I'm trying to get a refined unstructured mesh around my airfoil so that my y+ falls into the viscous sublayer region.
Is there any way to troubleshoot this problem?

I am facing the similar problem