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-   -   Does the wall BC set k & e to zero? (http://www.cfd-online.com/Forums/fluent/40864-does-wall-bc-set-k-e-zero.html)

 Lucy May 8, 2006 05:30

Does the wall BC set k & e to zero?

Hi,all!

I use the ske model and set the BC as "WALL" for some solid boundarys. But after caculation I ploted turbulence kinetic energy(k) along these "walls" and found them not equal to 0. Why???

I tried adding some source terms to the momentum equations, but the caculations diverged soon. I checked the values of k and found them quite large somewhere on the wall. I think this resulted in the divergence.

Can anyone tell me how fluent set the "WALL" BC? If I change the boundary condition "wall" to "velocity inlet" and set velocity,k and e to 0, is there any problem?

Any help will be very appreciated!

 Evan Rosenbaum May 8, 2006 12:39

Re: Does the wall BC set k & e to zero?

The default boundary condition for a wall is no-slip, so the immediately adjacent velocity is 0. Maybe if you set the walls to be slip walls (in the wall boundary condition panel) you would get nonzero k and e.

 Lucy May 8, 2006 21:53

Re: Does the wall BC set k & e to zero?

The problem is that I want k and e on the wall to be equal to ZERO but FLUENT actually don't set them to zeros in the default WALL boundary condition.

 Marta December 10, 2010 12:49

Hi guys!
I am trying to create a boundary condition in Fluent similar to the wall+source which can be found in CFX.
Do you know if it's possible for me to use any kind of udf to do this?

In particular what I would like to do is to add a mass flow rate source, instead of using the mass flow inlet boundary.
This is because i need to perform some other operations which are only allowed on walls.

Marta

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