3D simulations of self-propelled, video reconstructed jellyfish using vortex methods

Johannes Tophøj Rasmussen (Participant)

Activity: Attending an eventParticipating in or organising a conference

Description

We present the simulation of the swimming medusa by capturing the outline of the motion from video taped experiments. A three dimensional body with constant mass distribution and divergence solid velocity field is ensured under the assumption of a rotationally symmetric medusa. The simulations are carried out using the vortex-in-cell algorithm in three dimensions with one-way coupling from the medusa motion. The boundaries of the deforming solid body are enforced using Brinkmann penalization. The flow is discretized by 67M vortex particles and the computations carried out on 256 cores with a 80% parallel efficiency. The simulation is visualized in a fluid dynamics video. To different strokes, A and B, are captured, simulated and studied. Stroke A produces a starting vortex ring as fluid is being expelled from the bell and produces yet a vortex ring of opposite sign when the bell opens and recovers its shape. Stroke B is more brisk and differs from A by producing two vortex rings during the recovery stroke. Both strokes propel the medusa but stroke B produces a higher velocity. The crusing velocity scales with the square root of the Reynolds number.
Period22 Nov 200924 Nov 2009
Event typeConference
LocationAmerican Physical Society, 62nd Annual Meeting of the Division of Fluid Dynamics