[LiLAJ]

Hi all, I hope you're good.
I conduct a calculation in Fluent through natural convection in vertical channel study.
I would to compared results at different Rayleigh number 10**4, 10**5 , 10**6 , Ra=gB∆TL^3/Nu.alpha.
I reviewed some articles that mentioned to took the above parameters at T film.
if we asume that To is the fluid temperature, how can i calculate Ts the temperature of the heated area.