Modeling Laser ablation of Aluminum

Hi everyone :)
I use comsol 3.5 to model laser ablation of Aluminum in the following stack - Aluminum/Silicon nitride/Silicon. How to couple the heat transfer equations to the ablation and melting of Aluminum? I would also need to model the recoil of molten Aluminum material. From the previous comsol conference papers, I got the all equations in hand.

But I have a doubt whether the coupling should be done by incorporating heat transfer module and Fluid mechanics module and substitute appropriate sub domain boundary conditions for each of the material or use ALE to model the moving liquid once aluminum has reached melting point? (I need to see how solid aluminum changes to liquid phase and moves due to laser ablation)
If I use two separate modules and use appropriate sub domain boundary conditions, would melting and molten aluminum flow be visualizable in post processing?


My another doubt is, the laser beam has Guassian power distribution and Aluminum would have specific reflectivity for the beam. how to account for these effects in the model? In the weak form? If so kindly explain.

Thanks in advance :)