turbulence models
 

hi,

i'm in my final year at uni and i'm just starting a project researching the use of Fluent to analyse the flow around our SAE race car. Part of this research involves analysing the different models available within fluent and finding out the advantages, disadvantages and different applications of each, most importantly the Spalart-allmaras. Can anyone help me as i'm having difficulties finding information. any help would be greatly received

thanks

Dave

Re: turbulence models
 

hi. you probably already know this but i would suggest looking at the ideas behind zero, 1 and 2 equation models.

the SA model is a one equation model and would be expected to be less accurate than the ke model (a two equation model).

however from my experience of using fluent you will not necessarily find this is the case especially when studying extenal flows eg. around a car or aerofoil.

the ke model does not give good results around flow of strong streamlne curvature as in your case and the RNG variant should serve to improve this - however i suspect you may actually get better results from the one equation SA model than you may for the two equation RNG variant.

i would be interested to know if this is the case?

Re: turbulence models
 

well the team currently have used the SA model over tha past couple of years, but as i havent started any modelling yet, i cant really comment, but i will let you know as and when i do.

do you have any suggestions as to why the one equation SA model may give better results than the two equation RNG variant?

thanks

Dave

Re: turbulence models
 

For aero purposes you might as well consider LowRe k-e and k-Omega SST models that integrate to the walls.