Divergence issue with SST Turb Model
 

I am analyzing a propeller of an UAV. I have static thrust measurements such that when I used Euler results I got 3.5 lbf thrust as compared to the measured 6 lbs. My next step was to perform an NS equation with SA turb model. I got 7 times over predicted results such that the mesh has a Y+ of less than 1. Then I thought of doing an SST but was not long enough that it gave me error with divergence. I have been setting up my SST case as per the tutorial example of NACA0012. However, I do not happen to see any entry with regards to eddy frequency etc. (usually required by SST) in the config file. Any guidance will be great.

You can instead try specifying the FREESTREAM_TURBULENCEINTENSITY, which is set to 0.05 by default, and FREESTREAM_TURB2LAMVISCRATIO, which is set to 10 by default. Both of these options can be set in the config file.

Thanks

Let me try and will post my results.

Regards,

Hi,
I tried with:
FREESTREAM_TURBULENCEINTENSITY=0.001
FREESTREAM_TURB2LAMVISCRATIO = 100.0

but I am not sure if these are suitable as I got the following:
Free-stream viscosity (non-dim): 3.61984e-007
Free-stream turb. kinetic energy (non-dim): 0
Free-stream specific dissipation (non-dim): 0

Initialize Jacobian structure (Navier-Stokes). MG level: 0.
Initialize Jacobian structure (SST model).

----------------- Integration and Numerics Preprocessing ----------------
Integration Preprocessing.
Numerics Preprocessing.
Setting dynamic mesh structure.

------------------------------ Begin Solver -----------------------------

Setting rotating frame grid velocities.
Rotational origin (x,y,z): ( 0, 0, 0 )
Angular velocity about x, y, z axes: ( 0, 0, 628.318 ) rad/s

Maximum residual: -4.8402, located at point 57638.

Iter Time(s) Res[Rho] Res[kine] Res[omega] CThrust(Total) C
Torque(Total)
0 149.877000 -6.044197 1.#QNAN0 1.#QNAN0 1.196632e-003 1.77
8442e-003
1 142.350000 -6.044205 -16.000000 -10.059252 1.512296e+000 2.61
1483e+000
2 139.579000 -6.084640 -16.000000 -10.085875 2.813472e+000 4.90
3540e+000
3 138.195750 -6.131297 -15.946917 -9.946917 3.895072e+000 6.87
1384e+000
4 136.817200 -6.180195 -14.692565 -8.692565 4.754986e+000 8.50
6734e+000
5 135.953000 -6.225935 -13.091395 -7.091395 5.397893e+000 9.80
3564e+000
6 135.258000 -6.260035 -11.293994 -5.293994 5.833925e+000 1.07
6124e+001
7 134.779750 -6.273887 -9.338135 -3.338135 6.081352e+000 1.13
9192e+001
8 134.426667 -6.265993 -7.271303 -1.271303 6.164761e+000 1.17
1971e+001
9 134.119100 -6.243379 -5.132733 0.867267 6.115658e+000 1.17
8181e+001
10 134.201455 -6.214587 -2.937581 3.062423 5.966512e+000 1.16
2132e+001

!!! Error: NaNs detected in solution. Now exiting... !!!

It appears I am not seeting the Free stream turb. KE and free stream specific dissipation terms.
Thanks for your help.