Oscillating Velocity Inlet BC

evaliu246 · March 12, 2023, 18:44

I am trying to model my inlet velocity as being created by a piston-cylinder going forwards and backwards in CFX. Where my velocity profile will be either a square or sine wave, zero, wave, zero, repeating. How can I do this using CFX

Thanks!

ghorrocks · March 13, 2023, 02:01

Set the boundary to an inlet, and define the normal or cartesian velocity as a CEL expression which defines your function, such as 10[m/s]*sin(10[Hz]*t*2*pi)

Opaque · March 13, 2023, 10:28

Just be careful with your expression. If your oscillating boundary condition has an always positive inflow, you can use INLET; however, if you expect reverse flow at some times, you are better off using OPENING.

March 12, 2023, 18:44	Oscillating Velocity Inlet BC	#1
evaliu246 New Member Eva Liu Join Date: Nov 2022 Posts: 9 Rep Power: 4	I am trying to model my inlet velocity as being created by a piston-cylinder going forwards and backwards in CFX. Where my velocity profile will be either a square or sine wave, zero, wave, zero, repeating. How can I do this using CFX Thanks!

March 13, 2023, 02:01		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	Set the boundary to an inlet, and define the normal or cartesian velocity as a CEL expression which defines your function, such as 10[m/s]sin(10[Hz]t2pi) evaliu246 likes this. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

March 13, 2023, 10:28		#3
Opaque Senior Member Join Date: Jun 2009 Posts: 1,880 Rep Power: 33	Just be careful with your expression. If your oscillating boundary condition has an always positive inflow, you can use INLET; however, if you expect reverse flow at some times, you are better off using OPENING. evaliu246 likes this. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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