[shahidhk21]

If in my model boundary layer smoothly transitions to turbulence and develop naturally, what should I give in my config file to consider this? Do I need to give my transition model or only turbulent model is required?
See fig. for reference
Minf=2.5
Re=5.3e+7/m

[bigfootedrockmidget]

If your boundary layer transitions to turbulence then yes, you need the transition turbulence model for accurate results, specifically for skin friction.

https://su2code.github.io/tutorials/...al_Flat_Plate/