Average Nusselt Number computing
 

Hello CFD F riends , hope ur doing well
well,how to calculate the average nusselt number when we have a partially heated side (wall of cavity for ex. 40% of the height of cavity)?could u give me the formula plz.
Second , i d like to know : when we write a code '' fortran'' for computing average nusselt number ,wats the formula of the nusselt number(average) i mean to get convergence and that's make code stop runing.
third , i d like to get the velocity adimensiona on fluentl ,wats the formula of that please?
thank u so much ,hope u'll helping me very soon