# Boundary conditions for time varying crosswind

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 September 7, 2013, 02:31 Boundary conditions for time varying crosswind #1 New Member   Marijo Join Date: Jan 2011 Posts: 12 Rep Power: 8 Hello, I am trying to simulate a time-varying crosswind. I am having a problem with boundary condition set-up. If I want to simulate only the head wind, the set up is: inlet velocity, pressure outlet and lateral symmetry. If I want a steady crosswind then the boundary condition set-up is: head and side inlet velocity, and back and side pressure outlet. The problem comes when I need to simulate transient crosswind. My understanding is that I need to initialize with head wind and therefore the appropriate boundary conditions and than continue with introduction of crosswind. But I need to change the boundary condition appropriate for crosswind. If I switch the bcs the convergence is bad, the simulation needs time to adjust. Can I have one boundary condition set-up for both cases: headwind and crosswind, so I don't need to change bcs? Thank you! Marijo

April 10, 2015, 04:44
Did you solve it?
#2
New Member

Anikethan
Join Date: Sep 2014
Posts: 3
Rep Power: 4
Dear Krembil,

Did you find the solution for this problem ? I have similar setup. I am doing an unsteady crosswind simulation over the bus to check how CoP veries. Can you please tell me how did you do it. I have 2 weeks to complete the project and stuck with it. my guide is unaware how to do it.
Quote:
 Originally Posted by krembil Hello, I am trying to simulate a time-varying crosswind. I am having a problem with boundary condition set-up. If I want to simulate only the head wind, the set up is: inlet velocity, pressure outlet and lateral symmetry. If I want a steady crosswind then the boundary condition set-up is: head and side inlet velocity, and back and side pressure outlet. The problem comes when I need to simulate transient crosswind. My understanding is that I need to initialize with head wind and therefore the appropriate boundary conditions and than continue with introduction of crosswind. But I need to change the boundary condition appropriate for crosswind. If I switch the bcs the convergence is bad, the simulation needs time to adjust. Can I have one boundary condition set-up for both cases: headwind and crosswind, so I don't need to change bcs? Thank you! Marijo

 Tags boundary conditions, crosswind, fluent

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