Summary: This paper presents a multiphysics method for unsteady turbulent flows and fluid-structure computations. This method is based on a Galerkin least square finite element formulation for both solid and fluid equations. The viscous effects are taken into account using Spalart-Allmaras and \(k\)-\(\varepsilon\) turbulence models. The fluid boundaries motion is taken into account using an ALE formulation of the compressible equations. The fuid domain is then modeled as a hyperelastic material. For fluid-structure interaction problems, both solid and fluid equations are discretized in time using an implicit time-stepping scheme based on the Newmark’s one. Coupling between fluid and structure is achieved through non-matching interfaces. This numerical strategy is applied to a two-dimensional airfoil buffeting simulation, to a two-dimensional fluid-structure computation, and to a flutter analysis of a three-dimensional wing.