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SU2-NEMO sphere simulation diverges

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Old   January 23, 2024, 08:55
Default SU2-NEMO sphere simulation diverges
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Peter Lysdahl Bęk
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Hello

I am trying to simulate a sphere at Mach 15 using SU2-NEMO. So far when I run my simulation I get expected results for the first 1200-1300 iteration however afterwards the results seem to diverge (see the attached image).
I tried to reduce the Mach number to 10 where the same problems came, however at Mach 5 no problems were present.

What I can see from the results, the stagnation region does not grow as expected (the shock does not stay normal to the symmetry axis at higher iterations) which I expect to be the problem.

Has anyone had similar problems and if so, how did you solve them?

best.
Peter


Here is my config file
---------------------------------------------------------------------------------------------------------------------------------
MACH_NUMBER=15
AOA= 0.0
SIDESLIP_ANGLE= 0.0
FREESTREAM_PRESSURE= 21.96
FREESTREAM_TEMPERATURE= 246.87
FREESTREAM_TEMPERATURE_VE= 246.87
INIT_OPTION=TD_CONDITIONS

% ---- NONEQUILIBRIUM GAS, IDEAL GAS, POLYTROPIC, VAN DER WAALS AND PENG ROBINSON CONSTANTS -------%
%
FLUID_MODEL= SU2_NONEQ
GAS_MODEL= AIR-7
GAS_COMPOSITION= (5E-13, 0.767, 0.23, 0.001, 0.001, 0.000999999999, 5E-13)
TRANSPORT_COEFF_MODEL= GUPTA-YOS

% -------------------- BOUNDARY CONDITION DEFINITION --------------------------%
%
MARKER_ISOTHERMAL=(Wall, 300.0)
MARKER_FAR=(Inlet)
MARKER_OUTLET= (Exit, 21.96)%, symmetry, 21.96)
MARKER_SYM= (symmetry)

%MARKER_PLOTTING= (Wall)
%MARKER_MONITORING= (Wall)

% ------------- COMMON PARAMETERS DEFINING THE NUMERICAL METHOD ---------------%
%
NUM_METHOD_GRAD= WEIGHTED_LEAST_SQUARES
CFL_NUMBER= 3.0
ITER= 2500
LINEAR_SOLVER= BCGSTAB
LINEAR_SOLVER_ERROR= 1E-6
LINEAR_SOLVER_ITER= 5

% -----------------------------------------------------------------------%
%
CONV_NUM_METHOD_FLOW= AUSM
MUSCL_FLOW= YES
SLOPE_LIMITER_FLOW= VENKATAKRISHNAN
VENKAT_LIMITER_COEFF= 0.05
TIME_DISCRE_FLOW= EULER_IMPLICIT

% --------------------------- CONVERGENCE PARAMETERS --------------------------%
%
CONV_RESIDUAL_MINVAL= -20
CONV_STARTITER= 10

% ------------------------- INPUT/OUTPUT INFORMATION --------------------------%
%
MESH_FILENAME= SphereMesh.su2
MESH_FORMAT= SU2
SOLUTION_FILENAME= restart_flow_gy.dat
RESTART_FILENAME= restart_flow_gy.dat
TABULAR_FORMAT= TECPLOT
CONV_FILENAME= convergence
VOLUME_FILENAME= soln_volume
SURFACE_FILENAME= soln_surface
OUTPUT_WRT_FREQ= 100
SCREEN_OUTPUT= (INNER_ITER, RMS_DENSITY_0, RMS_DENSITY_1, RMS_DENSITY_2, RMS_DENSITY_3, RMS_DENSITY_4, RMS_DENSITY_5, RMS_DENSITY_6, RMS_ENERGY, RMS_ENERGY_VE, LIFT, DRAG, TOTAL_HEATFLUX)
Attached Files
File Type: pdf SU2_problem.pdf (154.2 KB, 19 views)
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Old   January 26, 2024, 18:11
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Hi,
Is this the Ma=15 flow over a cylinder from the testcases repository? If yes, was anything changed?
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Old   January 29, 2024, 05:25
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Peter Lysdahl Bęk
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Hello
Yes, I used the testcase repository where I could not find the proper mesh which lead me to create my own.
The only parts of the cfg file that should differ would be the CONV_RESIDUAL_MINVAL and OUTPUT_WRT_FREQ
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Old   January 29, 2024, 05:35
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Hi,
The meshes for the testcases are in a separate repository because of their size:

https://github.com/su2code/TestCases


Please try with the original mesh and see if that helps. If it does, you can compare the meshes and see where the differences are.
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Old   March 6, 2024, 21:29
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Liming Yang
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Quote:
Originally Posted by bigfootedrockmidget View Post
Hi,
The meshes for the testcases are in a separate repository because of their size:

https://github.com/su2code/TestCases


Please try with the original mesh and see if that helps. If it does, you can compare the meshes and see where the differences are.
I have calculated this example before, but can you tell me how the boundary is defined. Where is the symmetric boundary and where is the exit?
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File Type: jpg boundry.jpg (75.5 KB, 12 views)
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Old   March 8, 2024, 19:24
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Wally Maier
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Hi,

In the attached image, there is only a wall and farfield boundary condition.
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Old   March 14, 2024, 03:44
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Liming Yang
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Quote:
Originally Posted by wallym View Post
Hi,

In the attached image, there is only a wall and farfield boundary condition.
However, in the provided cfg file, there are symmetric boundaries that are not represented in the grid.
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divergence, hypersonic flow, nemo

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