k Wall function using a fixed gradient

agustinvo · September 16, 2014, 11:27

Good afternoon,

during my project I have to implement as a boundary condition for the turbulent kinetic energy:

$\frac{\partial k}{\partial n} =2 \frac{k}{\delta}$

but every wall function I have checked they use a fixed value instead of a gradient. I would like to know if there is a simple way to reach it, or if I have to use a fixedGradient BC and modify it (I have been told that to implement this new wall function is not the best idea)...

Any suggestions? Thanks in advance!

mohsen cheraghi · September 16, 2014, 14:16

Quote:

Originally Posted by agustinvo

Good afternoon,

during my project I have to implement as a boundary condition for the turbulent kinetic energy:

$\frac{\partial k}{\partial n} =2 \frac{k}{\delta}$

but every wall function I have checked they use a fixed value instead of a gradient. I would like to know if there is a simple way to reach it, or if I have to use a fixedGradient BC and modify it (I have been told that to implement this new wall function is not the best idea)...

Any suggestions? Thanks in advance!

Hi,
For velocity, there are a partial slip boundary condition which is in the form. Maybe you can start with it and modify it for scalars.
bests.

September 16, 2014, 11:27	k Wall function using a fixed gradient	#1
agustinvo Senior Member Agustín Villa Join Date: Apr 2013 Location: Alcorcón Posts: 314 Rep Power: 15	Good afternoon, during my project I have to implement as a boundary condition for the turbulent kinetic energy: $\frac{\partial k}{\partial n} =2 \frac{k}{\delta}$ but every wall function I have checked they use a fixed value instead of a gradient. I would like to know if there is a simple way to reach it, or if I have to use a fixedGradient BC and modify it (I have been told that to implement this new wall function is not the best idea)... Any suggestions? Thanks in advance!

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