[fluidmechanics]

Dear All

I am studying hypersonic flow over a sphere using SST turbulence model. using constant turbulent prandtl number as 0.9, wrong (high) heat flux is computed at stagnation point. It seems that variable turbulent prandtl number is necessary in order to compute turbulent conductivity. Turbulent conductivity is computed high at stagnation results in high heat flux.


Thanks for any idea

[lcarasik]

Originally Posted by fluidmechanics

Dear All

I am studying hypersonic flow over a sphere using SST turbulence model. using constant turbulent prandtl number as 0.9, wrong (high) heat flux is computed at stagnation point. It seems that variable turbulent prandtl number is necessary in order to compute turbulent conductivity. Turbulent conductivity is computed high at stagnation results in high heat flux.


Thanks for any idea

Wait, what are you asking?

[fluidmechanics]

Hi,

I want to know if it is necessary to use a variable turbulent prandtl number for hypersonic flows in order to compute wall heat flux well. If so, what's that variable turbulent prandtl function?

[LuckyTran]

Originally Posted by fluidmechanics

Hi,

I want to know if it is necessary to use a variable turbulent prandtl number for hypersonic flows in order to compute wall heat flux well. If so, what's that variable turbulent prandtl function?

In general the answer is yes.

That variable turbulent Prandtl function is not trivial, coming up with one is the same level of difficulty as coming up with a turbulence model. It is a turbulence model, but for the energy equation instead of the momentum equation. You would have to really read some papers and find some literature on this topic. But nowadays, few people are working on turbulence models and even fewer are working on energy models.