View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0003073 | OpenFOAM | Bug | public | 2018-09-17 19:38 | 2018-09-20 11:38 |
| Reporter | Taihang | Assigned To | henry | ||
| Priority | normal | Severity | major | Reproducibility | always |
| Status | closed | Resolution | no change required | ||
| Platform | GNU/Linux | OS | Ubuntu | OS Version | 16.04 |
| Summary | 0003073: kOmegaSSTDES model converged to unphysical result | ||||
| Description | I was using kOmegaSSTDES turbulence model to run a simulation at deltaT = 0.000002. The max Courant number is less than 0.01, but the result is clearly unphysical. I then decreased deltaT to 0.000001. The result is much better but the time cost is increased. I was looking for the reason so I changed the turbulence model to dynamicKEqn with deltaT = 0.000002. the converged result is also physical. It seems that there is a problem with the kOmegaSSTDES turbulence model, which will result in unphysical result unless we limit the deltaT less than 0.000001. I am wondering if there is something wrong with my case or kOmegaSSTDES model. My case files have been attached. There are three sets of result figures in my file. Result 1 corresponds to kOmegaSSTDES with deltaT = 0.000002, which is the unphysical result. Result 2 is kOmegaSSTDES with deltaT = 0.000001. Result 3 is dynamicKEqn with deltaT = 0.000002. | ||||
| Steps To Reproduce | To reproduce result 1, you can use the following command in my file folder decomposePar mpirun -np 8 pimpleFoam -parallel paraFoam -builtin To reproduce result 2, please change the deltaT in controlDict to 0.000001, then decomposePar -force mpirun -np 8 pimpleFoam -parallel paraFoam -builtin To reproduce result 3, please change the deltaT in controlDict to 0.000002, and change the turbulenceProperties to dynamicKEqn, then decomposePar -force mpirun -np 8 pimpleFoam -parallel paraFoam -builtin | ||||
| Tags | No tags attached. | ||||
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We have also seen problem with the behavior of the k omega SST DES model and do not recommend it. |
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Hi, I think you should not use DES for 2D case. Because the spanwise grid spacing will greatly dominate the solution by effecting delta (in your case you use maxDeltaxyz). 2D simulation with DES is also not recommended by Philippe Spalart, as stated in his presentation entitled "THE USES OF DES: NATURAL, EXTENDED, AND IMPROPER" at the DESider conference. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2018-09-17 19:38 | Taihang | New Issue | |
| 2018-09-17 19:38 | Taihang | File Added: SST_2D3.zip | |
| 2018-09-17 19:49 | henry | Note Added: 0010062 | |
| 2018-09-19 06:50 | wwzhao | Note Added: 0010063 | |
| 2018-09-20 11:38 | henry | Assigned To | => henry |
| 2018-09-20 11:38 | henry | Status | new => closed |
| 2018-09-20 11:38 | henry | Resolution | open => no change required |
