Turbulence Model for Confined Jets

lucasphp · June 3, 2014, 20:48

Good afternoon,

I am studying the impact force produced by a jet colliding against a wall.
The distance between the eject nozzle and the wall is variable.

The study fluid is water and the Re on the nozzle is about 80000. The turbulence model chosen is the SST.

After some tests, I noticed that the SST model doesn't fit exactly with the experimental data. To explain better my question, there is a curve in the attachment (from a study about evaluation of modified two-equation turbulence models for jet flow predictions.) that compares different turbulence models on the centerline velocity of a jet.

The problem is the delay in velocity to decrease, which is generating impact force larger than the experimental data in that range.

So, the question is: Is the SST model the best turbulence model available on CFX or you, CFD experts, have a better solution for me?

Thank you,
Lucas

ghorrocks · June 4, 2014, 07:26

Have you done the basic accuracy checks? http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

In particular have you checked the inlet and atmospheric turbulence intensity is correct?

June 3, 2014, 20:48	Turbulence Model for Confined Jets	#1
lucasphp New Member Lucas Figueiredo Join Date: Jan 2013 Posts: 8 Rep Power: 13	Good afternoon, I am studying the impact force produced by a jet colliding against a wall. The distance between the eject nozzle and the wall is variable. The study fluid is water and the Re on the nozzle is about 80000. The turbulence model chosen is the SST. After some tests, I noticed that the SST model doesn't fit exactly with the experimental data. To explain better my question, there is a curve in the attachment (from a study about evaluation of modified two-equation turbulence models for jet flow predictions.) that compares different turbulence models on the centerline velocity of a jet. The problem is the delay in velocity to decrease, which is generating impact force larger than the experimental data in that range. So, the question is: Is the SST model the best turbulence model available on CFX or you, CFD experts, have a better solution for me? Thank you, Lucas

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June 4, 2014, 07:26		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	Have you done the basic accuracy checks? http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F In particular have you checked the inlet and atmospheric turbulence intensity is correct?