Dynamically coupled fluid–body interactions in vorticity-based numerical simulations

A novel method is presented for robustly simulating coupled dynamics in fluid–body interactions with vorticity-based flow solvers. In this work, the fluid dynamics are simulated with a viscous vortex particle method. In the first substep of each time increment, the fluid convective and diffusive processes are treated, while a predictor is used to independently advance the body configuration. An iterative corrector is then used to simultaneously remove the spurious slip – via vorticity flux – and compute the end-of-step body configuration. Fluid inertial forces are isolated and combined with body inertial terms to ensure robust treatment of dynamics for bodies of arbitrary mass. The method is demonstrated for dynamics of articulated rigid bodies, including a falling cylinder, flow-induced vibration of a circular cylinder and free swimming of a three-link ‘fish’. The error and momentum conservation properties of the method are explored. In the case of the vibrating cylinder, comparison with previous work demonstrates good agreement.