Shallow channel Approximation

Hello,

I'm using COMSO 4.4 (Classkit version) and under laminar flow "use shallow channel approximation" option is missing. Actually it should be under Laminar flow------>turbulent model type-----> ***** . The whole turbulent model type part is missing. Is it something wrong with classkit version or different made for 4.4 version. Your comments are much appreciated!

Thanks