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 Ssn January 25, 2008 04:43

Wall boundary condition – UDF

Dear All,

I have gas-solid flow in 2D domain and would like to specify a wall boundary condition for solid phase. Radial velocity of particles should be zero at wall and for axial velocity there is a correlation;

-----------------------------------------------------------

Up=(dp/Ep**0.333)*d(Up)/dr @ r=R

dp=solid diameter

Ep=solid holdup

d(Up)/dr= partial derivation with respect to r

-----------------------------------------------------------

I know that I should do it by UDF - coupled at specified shear panel. Parameters will be;

y_vel_s = C_V (cell,thread_s) ->tangential velocity-to-wall

diam = C_Phase_Diameter (cell, thread_s)

void_g = C_VOF (cell, thread_g)

*******************************

Shear = -Mu*dV/dr

Shear stress y component; Shear_y = Visco*pow((1-void_g),(1/3))/diam*y_vel_s

I don't know how to define shear stress x component? And also I am not sure if I can use the above shear definition at wall?

Does anyone have an experience with this type of bc and UDF??

Regards,

Ssn

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