Slip flow boundary condition on wall using UDFs

mahdi haddad

Dear all I want to simulate the flow through a convergent-divergent micro nozzle using fluent 6.1.22 . The Knudson number is 0.05. How can i use the equation Us=Kn*dUs/dn on the wall using UDFs and how can i activate it in the fluent. As you may know fluent handles the no slip boundary condition on the wall using some nodes behind the wall. it gives the velocity of those nodes equal to but opposite of the velocity of nodes up the wall.what about having a non zero velocity on the wall.The problem is to give a velocity to the behind-the-wall nodes to give us an appropriate velocity on the wall.

I will appreciate who can send me a source file to solve the problem.

Thank you very much and in advance

Bye