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-   -   Ramping Boundary Condition for Steady FSI Simulation (http://www.cfd-online.com/Forums/cfx/106153-ramping-boundary-condition-steady-fsi-simulation.html)

ashtonJ August 20, 2012 22:32

Ramping Boundary Condition for Steady FSI Simulation
 
Dear all,

I am doing steady FSI modelling in an artery model.

I know how to ramp the pressure boundary condition for transient FSI case; however, I don't know how to ramp the pressure boundary condition for steady FSI.

In transient modelling, because the pressure is dependent on time, so the time can be used as an independent variable to ramp the boundary condition like below

P=12*10*t*step((0.1-t))+12*step((t-0.1))

Although for steady flow there is not any independent variable to be used for ramping.

I would be too pleased if any could help me.

Regards,
AshtonJ

Lance August 21, 2012 02:25

Do a transient simulation first and use the results as input for your steady simulation?

ashtonJ August 21, 2012 03:13

Thank you. To be honest, I cannot understand what you mean!

Just letting you know that first I need to run steady case then use the steady case results as the initial condition for transient case. I’ve had difficulty in converging the steady case with applied boundary condition, so I am trying to ramp the boundary condition to see if it helps.

Regards,
AshtonJ

Lance August 21, 2012 03:18

I see. I thought you wanted to do a steady FSI.

If you are going to ramp up your BCs you need to to a transient analysis to reach a steady-state from where you can continue with your "real" BCs. Then just use the last results from the ramping transient analysis as initial condition.


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