Meeting Abstract
Remora fishes possess a unique dorsal pad capable of forming reversible, suction-based attachment to a variety of host organisms and marine vessels. Although several investigations of the suction pad have been carried out, much less attention has been given to fluid drag despite it being the principal force that remoras must resist. Here a theoretical estimate of the drag experienced by a remora attached to a host is presented using computational fluid dynamics (CFD) informed by actual remora geometry obtained from micro-computed tomography. The simulated flows were compared to measured flow fields of a euthanized specimen in a flow tank. Additionally, the impact of the host’s boundary layer was investigated, and scaling relationships between remora features were computed from the digitized geometry. The results suggest the drag on an attached remora is analogous to that of a non-lifting, streamlined body with the host’s boundary layer playing a minimal role. Consequently, this evidence does not support previous hypotheses that remoras choose attachment locations for hydrodynamic considerations. Comparison of the simulated drag with experimental friction tests showed that, even at elevated swimming speeds, it is unlikely a remora will be dislodged solely by drag forces, and furthermore that larger remoras are more likely to remain attached to a host than smaller remoras at the same swimming speed. This may indicate remoras become more suited to attachment as they mature.
