Meeting Abstract

6.3  Saturday, Jan. 4 08:30  Tuning the velar kinematics of the hydromedusa Sarsia tubulosa for targeted swimming performance STEWART, C. J.*; MARUT, K. J.; TAFTI, D. K.; PRIYA, S.; Virginia Tech; Virginia Tech; Virginia Tech; Virginia Tech colins@vt.edu

Fast-swimming hydromedusae produce the majority of their thrust by expelling pulsed jets of water from their subumbrellar oral cavity, with the remaining thrust produced after each pulse, during refilling, when high-speed fluid enters the cavity and stagnates against the surface. Whether exiting or entering the cavity, in both cases the flow interacts with the nozzle-like flexible velum at the cavity orifice and causes it to deform in the flow direction. Previous studies show that velar deformation during fluid expulsion serves to optimize the formation of the starting vortex such that thrust is maximized while energetic cost is minimized, but little has been reported about the influence of velar deformation on thrust production or vortex wake during refilling. In this study, we use a computational fluid dynamics (CFD) model of the hydromedusa Sarsia tubulosa to investigate a wide range of velar kinematics, both passive and imposed, and how they can be tuned to fully exploit both thrust producing events in order to maximize swimming proficiency or efficiency.