| In this talk, I will discuss various variational procedures that give the coupled hydrodynamic models for different complex fluids. We will study the capillary force in the mixtures, the Lorentz force in MHD, hyper-viscoelasticity, liquid crystals and polymeric fluid. Such an approach will be valid for the quasi-thermostatic dynamics and gives the natural energy dissipation of the system. I will also discuss some analytical, as well as practical issues of the method. |