| In this thesis, we focus on the problem of interactions between solids and fluids.;The main part is the study of the motion of a rigid body immersed in an incompressible fluid. First, for the case of 2D ideal flow, a global weak solution is derived. Second, for the case of viscous flow in 3D, the problem is investigated in the Lp--framework. We get a decomposition of Lp-space associated with the problem. Then We prove that the corresponding semigroup is analytic in L65 R3∩L pR3 (p ≥ 2). Our result yields a local in time existence and uniqueness of strong solutions taking initial data in L65 R3∩L pR3 (p ≥ 3).;The other part is some research about micro-macro models of polymeric fluids. We provide a new proof for the global well-posedness of the coupling systems in 2D. |
