A linearized ALE Boundary Element Method for flexible 3D bluff bodies in potential flows: Towards application to airship aeroelasticity

Effects of fluid–structure coupling on the dynamic behavior of flexible airships can be modeled with a potential, incompressible, inviscid flow. A new formalism to study the linear behavior of a fluid–structure interface in a time-dependent ambient flow is introduced. The fluid equations are condensed at the interface with the help of integral equations, which are expressed as a function of the structure variables defined on a time-independent reference configuration with an Arbitrary Lagrangian–Eulerian (ALE) formalism. The features of the Boundary Element Method (BEM) used to solve this problem numerically are exhibited. The approximations of this method associated with both linearization and discretization are quantified to validate the model. A simplified flexible airship test case model is studied to illustrate a practical application of the method.