| Summary: | European eels (Anguilla anguilla) undertake a 5000-km spawning migration from Europe to the Sargasso Sea although they do not feed during the migration. Indeed swimming organisms at large have refined their senses, morphologies, gaits and mechanical properties to effectively propel and maneuver in a variety of unsteady flow conditions. The understanding of new design paradigms that exploit flow induced mechanical instabilities for propulsion or energy harvesting demands robust and accurate flow structure interaction numerical models. In this context, we develop a novel two dimensional algorithm that combines a Vortex Particle-Mesh (VPM) method and a Multi-Body System (MBS) solver for the simulation of passive and actuated structures in fluids. This method further captures dynamic interactions between the fluid and articulated structures that can be either discontinuous or continuous. The hydrodynamic forces and torques are recovered through an innovative approach which crucially complements and extends the projection and penalization approach of previous contributions. The resulting method avoids time consuming computation of the stresses at the boundary between the swimming bodies and the fluid to recover the force distribution on the surface of complex deforming shapes. This feature distinguishes the proposed approach from other VPM formulations. The methodology is verified against a number of benchmark results ranging from the sedimentation of a 2D cylinder to the extraction of actuation torques needed for propulsion of continuous swimmer. We then showcase the capabilities of this method through the study of an energy harvesting structure, the study of a drafting strategy in the wake of a cylinder and the study of the propulsion of a continuous swimmer. (FSA - Sciences de l'ingénieur) -- UCL, 2021
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