EpsilonBoundaryCondition

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C0st4s
Posts: 44
Joined: Fri May 11, 2018 12:21 pm

EpsilonBoundaryCondition

Post by C0st4s » Mon Mar 23, 2020 11:35 am

Hi,

I am trying to impose an epsilon boundary condition to the near wall node I that is equal to the one proposed by Chien and Launder (1980) paper. The approach is to tweak the discretised equation of the near wall node by using a big source term and an imposed value equivalent to the equilibrium lenght scale if y+>5.1. The implementation seems to be ok but I am testing the approach on a rectangular cavity and it seems that something goes wrong (
Selection_075.png
code attached). A few questions:
1) Does the imposed value need to be assigned to the pointer cvar_ep(iel) or to a new dynamic array ?
2) Is there any examples on how to do a weighting when there are 2 boundary faces for a single cell volume?
3) Is epsilon equation solved before k when ikecou=0?

Best regards,
Costas

Yvan Fournier
Posts: 2871
Joined: Mon Feb 20, 2012 3:25 pm

Re: EpsilonBoundaryCondition

Post by Yvan Fournier » Tue Mar 24, 2020 4:41 pm

Hello,

Could you be more specific in "something goes wrong" ?

1) If you want to impose a value, you can either use source terms (as seems to be the case here), or boundary conditions. Neither is directly in cvar_ep(iel)

2) not to my knowledge. Cells with multiple boundary faces are mostly in ridges and corners, in which wall models are usually not so good anyways.

3) I am not sure. you would need to check in the source code, or simply use a higher verbosity in the numerical options so as to see which is solved first.

Best regards,

Yvan

C0st4s
Posts: 44
Joined: Fri May 11, 2018 12:21 pm

Re: EpsilonBoundaryCondition

Post by C0st4s » Thu Mar 26, 2020 7:33 pm

Hi Yvan,

Thanks for the reply,
Costas

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