What are some potential solutions to address buoyantFoam crashes during mixed convection simulations in OpenFOAM?
I'd be glad to help you with the buoyantFoam crashes you're encountering in mixed convection simulations or when using higher-order schemes.
Understanding the Issue:
The forum post you referenced highlights several key points:
* Crash during p_rgh iterations: The simulation crashes during pressure correction iterations, indicating a potential problem with pressure-velocity coupling, especially in natural convection-dominated cases.
* Sensitivity to divergence scheme: The choice of the divergence scheme for the velocity term ("div(phi,U)") significantly impacts stability.
* Success with lower-order schemes and forced convection: The simulation works well with upwind schemes and forced convection scenarios in ANSYS Fluent.
Possible Solutions:
* Examine Relaxation Factors:
* The post suggests that reducing relaxation factors might improve stability. Experiment with different relaxation factors for pressure, velocity, and turbulence equations.
* Explore Alternative Divergence Schemes:
* Try using alternative divergence schemes like "central differencing" or "corrected Gauss upwind" to see if they enhance stability.
* Consider Pressure Boundary Conditions:
* Ensure that appropriate pressure boundary conditions are applied, especially for outlets in natural convection cases.
* Test with Steady-State Conditions:
* If possible, start with a purely forced convection case and gradually reduce the inlet velocity to approach mixed convection. This can help isolate the issue.
* Investigate DES (Detached Eddy Simulation) Settings:
* If you're using DES, double-check the DES settings and consult the OpenFOAM documentation for recommended practices in mixed convection scenarios.
Additional Tips:
* Refer to the OpenFOAM user guide and tutorials for mixed convection simulations and DES.
* Consider seeking help on the OpenFOAM forum, providing more details about your case setup and the specific error messages you're encountering.
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