Simulating Goertler vortices in cfx

bingo10 · December 11, 2012, 12:16

Hi,
I'm new to the field of cfd and am trying to do a simulation of a hypersonic flow (Ma 6.85) over a compression ramp. The goal is to show the Goertler vortices (counter rotating vortices), which should emerge behind the seperation bubble. I have tried to simulate it as a laminar and turbulent flow and have created some sinusoidal disturbances in the lateral velocity distribution. I also used different meshes, but if it gets to fine the whole simulation becomes unstable.
But so far I've had very little succes when it comes to the Goertler vortices, because they don't exist in my simulation.

Can anyone tell me if it's possible to simulate such a flow with cfx and if theres something special I need to consider?

I can post additional information if that is necessary.

Greetings bingo10

ghorrocks · December 11, 2012, 18:14

As long as no dissociation effects occur you should be able to model this in CFX. But detailed features like this will require an accurate setup and careful modelling.

I recommend you do some benchmark cases first to make sure you know how to do accurate CFD. Things like a supersonic boundary layer development, a convergence-divergent nozzle, flow over a sphere at supersonic speeds would be good. You should be able to find good experimental and/or simulation models of these cases so if you can model these accurately you are in a good position to model your case.

December 11, 2012, 12:16	Simulating Goertler vortices in cfx	#1
bingo10 New Member Join Date: Dec 2012 Posts: 3 Rep Power: 14	Hi, I'm new to the field of cfd and am trying to do a simulation of a hypersonic flow (Ma 6.85) over a compression ramp. The goal is to show the Goertler vortices (counter rotating vortices), which should emerge behind the seperation bubble. I have tried to simulate it as a laminar and turbulent flow and have created some sinusoidal disturbances in the lateral velocity distribution. I also used different meshes, but if it gets to fine the whole simulation becomes unstable. But so far I've had very little succes when it comes to the Goertler vortices, because they don't exist in my simulation. Can anyone tell me if it's possible to simulate such a flow with cfx and if theres something special I need to consider? I can post additional information if that is necessary. Greetings bingo10

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December 11, 2012, 18:14		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	As long as no dissociation effects occur you should be able to model this in CFX. But detailed features like this will require an accurate setup and careful modelling. I recommend you do some benchmark cases first to make sure you know how to do accurate CFD. Things like a supersonic boundary layer development, a convergence-divergent nozzle, flow over a sphere at supersonic speeds would be good. You should be able to find good experimental and/or simulation models of these cases so if you can model these accurately you are in a good position to model your case.