Modeling of Pulsing Corals and Mixing*

The motion of pulsing corals, a soft coral belonging to the Xeniidae family, is highly intriguing because of the unique movement that it uses to generate fluid flow around it. This energetically expensive motion is not used for locomotion but is instead believed to aid the photosynthesis process for their endosymbiotic algae. The photosynthetic algae live within the coral tissue  and produce energy for the coral polyp. We solve for the flow created by the pulsing coral using  anodal immersed finite element-finite difference method, an off-shoot of the classic immersed boundary method to model this fluid-structure interaction process. We then employ a mix of analyses to quantify the flow and mixing over a pulsing period. Additionally, we vary the kinematic, flow, and muscle parameters that govern the resulting tentacle motion and fluid flow to understand the parameters that result in more or less mixing.