Guys,

I got a question regarding viscosity setting in Fluent. I am modeling a subsonic/supersonic case (turbomachinery). My question is that should I set the viscosity to be constant (density is set to ideal-gas) or should it be a function of temperature (linear, power law, etc)? The reason I am asking is that viscosity is temperature dependent in compressible case theoretically, but in the nozzle tutorial of Fluent 6 (supersonic case) they leave viscosity as constant.

Your help would be greatly appreciated.

Thanks a lot!

I'd recommend using the three-coefficient Sutherland law.

Thanks a lot!!!!! I will do that.