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Transient Boundary Condition in Steady state solution

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Old   March 30, 2021, 00:32
Default Transient Boundary Condition in Steady state solution
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RAJDEEP JAGDALE
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Can constant magnitude of transient boundary condition provide well converged steady state solution?

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Old   March 30, 2021, 01:32
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Hi,

Do you mean using a transient BC in a steady state simulation ?

If not, in a transient simulation, constant magnitude of transient BC will yield in a "statistically steady state" solution with a sufficient run time.
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Old   March 30, 2021, 02:24
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Hi,

I mean by using Transient BC in Steady State Simulation like shaft rotation at particular constant speed which i am specifying in the CFX pre in rad/sec.
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Old   March 30, 2021, 02:36
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Fluid flow is by its definition transient - the stuff is moving. But in a finite volume solver like CFX, if you can assume that when you define a volume you are simulating that the boundary conditions do not change with time and the fluid condition at all points in the volume do not change with time then it is a steady state simulation.

So think about whether the boundary condition changes the simulation volume. For example, if a wall has a tangential velocity this can be modelled by a tangential velocity on the wall but the simulation volume is not changed - therefore it is steady state. If you have a wall with a normal velocity this will change the simulation volume - therefore it is transient.
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