Model Wizard
The first step to build an application is to open COMSOL Desktop, then select the physics interface and specify the type of analysis you want to do — in this case, a stationary, Turbulent Flow, k-ε analysis.
1
Open COMSOL Multiphysics. On the New page click Model Wizard . Then click the 3D button .
2
In the Select Physics tree under Fluid Flow > Single-Phase Flow > Turbulent Flow, click Turbulent Flow, k-ε (spf) .
3
Click Add and then click the Study button 
4
In the tree under General Studies, click Stationary .
5
Click the Done button .