Learning Forum

[ztjia]

when I use the SAS-SST  model, I do not understand the epsilon(turbulence/turbulent dissipation rate epsilon). Does the "epsilon" represent the turbulent dissipation rate in SAS-SST model? I know that SAS-SST model can tranfer to the LES-like mode in the unsteady flow, so is the turbulent dissipation rate in SAS-SST model calculated by " effective viscosity*strain rate*strain rate"? hoe you can help me, thank you, waiting for your reply. Also, how to calculate the dissipation rate in the SBES model (k-omega SST)?

[Essence]

Yes, epsilon is the turbulent dissipation rate. Please refer to the Ansys guide link:

https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v232/en/flu_th/x1-1810005.20.2.html

https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v232/en/flu_th/flu_th_sec_turb_scales_SBES.html?q=sbes

[ztjia]

sorry,the link I can not open

[ztjia]

sorry, I can not open the link?is there any problem?

[Rob]

Click on Help in Fluent & paste the above into the browser that opens. Documentation is password protected but the solvers have a token/cookie/biscuit to bypass that step. 

[ztjia]

thanks for your reply. there still are some questions. for example, when I use SBES model based on the k-omega SST, how to calculate the subgrid viscosity? does the effective viscosity in fluent(Turbulence variable) include the subgrid viscosity? and under the SBES model, does S(strain rate tensor) represent the instantaneous velocity?