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why does slip velocity take no changes?

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Old   April 25, 2007, 06:39
Default why does slip velocity take no changes?
  #1
Wang
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Hi,In my case

slip velocity: u_wall=B*du_wall/dy.

B is the slip length.

shear stress : t_wall=A*du_wall/dy.

I have to contain B in my UDF program. I use the equation t_wall=(A/B)*u_wall instead of t_wall=A*du_wall/dy.So when I changed the slip coefficient B,the flow should also change But the result seem not so.Flow rate is always the same when B changes.I don't know how mistakes accure, could you please help me?

I wrote a UDF to simulate slip boundary condition.and hooked it at the specified shear.

My UDF is below: ---------------------- DEFINE_PROFILE(slip_wall,thread,index) { ...

begin_f_loop(f,thread) {

if(time<0.001)

F_PROFILE(f,thread,index)=0;

else

{

c=F_C0(f,thread);

cell_thread=THREAD_T0(thread);

F_PROFILE(f,thread,index)=coef*C_U(c,cell_thread);

} } end_f_loop(f,thread) } -------------------------------

best regards!

Wang
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Old   June 26, 2010, 09:23
Default hi wang,slip velocity ,help!
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王国斌
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hello, wang,
i am studying at beijing, where are you now?
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