S-A model-why sometime trim functions are not used
 

Hello everyone, In S-A turbulence model, the trim functions are not used some times, probably for supercritical flows. Can anyone explain please?

Re: S-A model-why sometime trim functions are not
 

There are term including ft as trip functions to facilitate transition to turbulent in S-A model. However, I have seen some papers which dont use it quoting supercritical flow. Can someone please guide me why? Thanks in anticipation.