Urgent: Boundary condition
 

I want to simulate a turbulent flow in a rectangular channel, at the outflow boundary, zero-gradient conditions are imposed for all dependent variable. Which is the condition which I must use: pressure outlet or outflow?

Re: Urgent: Boundary condition
 

i think pressure flow BC would be more suitable for incompressible flow as u are using the 0-gradient conditions, outflow BC are used where information about the velocity & press are not know at the outlet of the sytem