Particle capture by plumose sea anemone during flow-induced bending

Passive suspension feeders exposed to unidirectional flow exhibit some form of deformation, including bending and shearing, resulting in a tradeoff between drag reduction and feeding via suspended particle capture. In the presence of ambient currents, the plumose sea anemone (Metridium senile) exhibits downstream bending of its trunk that is attached to numerous tentacles. While studies have indicated that feeding mechanisms depend on both their flow habitat and body size, the influence of flow-induced deformation of the trunk and the filtering structure (i.e., tentacles) on the flow dynamics, particle capture, and drag remains unclear. 2D PIV measurements were conducted on physical models of flexible M. senile to observe the flow-induced deformation of the trunk and filtering structures. To examine the role of tentacle ‘packing’, 3D CFD simulations were conducted on a numerical model of M. senile, where the tentacles were idealized as a porous hemispherical bell via Darcy approximation. Discrete phase modeling was used to examine the particle dynamics around various deformed M. senile models. Findings indicate that high ambient flow forces modify the filtering structure and displace it towards the wake and boundary layer, promoting particle retention and capture.