Is it possible in FLUENT

August 19, 2003, 23:45

hi is it possible to determine boundary layer transition (from laminar to turbulent) along the length of a body in turbulent flow, using FLUENT or any other cfd codes, OR IS IT NOT POSSIBLE AT ALL

August 20, 2003, 15:48

Some people will tell you that it is possible to predict transition with the two-equation models available in Fluent and other codes. However, this is only in theory and only in the special case of by-pass transition, ie transition caused by a very high free-stream turbulence level.

In practise most CFD codes with a two-equation eddy-viscosity model will give you turbulent boundary layers immediately and hence are not able to predict any transition. My advice is that you don't even try to predict transition just using a CFD code with a two-equation eddy-viscosity model.

The only reasonably reliable "industrial" way to predict transition is to use an ad-hoc transition model tuned for your specific application. Fluent does not have any such models.

August 21, 2003, 00:48

Thank You Mr Larsson. This saves a lot of time and effort

August 21, 2003, 00:48

Thank You Mr Larsson. This saves a lot of time and effort

August 19, 2003, 23:45	Is it possible in FLUENT	#1
kumar Guest Posts: n/a	hi is it possible to determine boundary layer transition (from laminar to turbulent) along the length of a body in turbulent flow, using FLUENT or any other cfd codes, OR IS IT NOT POSSIBLE AT ALL

August 20, 2003, 15:48	Re: Is it possible in FLUENT	#2
Jonas Larsson Guest Posts: n/a	Some people will tell you that it is possible to predict transition with the two-equation models available in Fluent and other codes. However, this is only in theory and only in the special case of by-pass transition, ie transition caused by a very high free-stream turbulence level. In practise most CFD codes with a two-equation eddy-viscosity model will give you turbulent boundary layers immediately and hence are not able to predict any transition. My advice is that you don't even try to predict transition just using a CFD code with a two-equation eddy-viscosity model. The only reasonably reliable "industrial" way to predict transition is to use an ad-hoc transition model tuned for your specific application. Fluent does not have any such models.

August 21, 2003, 00:48	Re: Is it possible in FLUENT	#3
kumar Guest Posts: n/a	Thank You Mr Larsson. This saves a lot of time and effort

August 21, 2003, 00:48	Re: thanks	#4
kumar Guest Posts: n/a	Thank You Mr Larsson. This saves a lot of time and effort

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