Stochastic phase field $\alpha$-Navier-Stokes vesicle-fluid interaction model.

International audienceWe consider a stochastic perturbation of the phase field alpha-Navier-Stokes model with vesicle-fluid interaction. It consists in a system of nonlinear evolution partial differential equations modeling the fluid-structure interaction associated to the dynamics of an elastic vesicle immersed in a moving incompressible viscous fluid. This system of equations couples a phase-field equation-for the interface between the fluid and the vesicle-to the alpha-Navier-Stokes equation-for the viscous fluid-with an extra nonlinear interaction term, namely the bending energy. The stochastic perturbation is an additive space-time noise of trace class on each equation of the system. We prove the existence and uniqueness of solution in classical spaces of $L^2$ functions with estimates of non-linear terms and bending energy. It is based on a priori estimate about the regularity of solutions of finite dimensional systems, and tightness of the approximated solution. AMS 2000 subject classifications. 60H15, 60H30, 37L55, 35Q30, 35Q35, 76D0