Improving Attachments of Non-Invasive (Type III) Electronic Data Loggers to Cetaceans

As sensing and electronic technology has improved, the use of bio-logging tags for the study of marine mammals has steadily grown. These tags require the electronics to be packaged in a housing that protects it from the environment, maintains proper configuration of the sensors, and provides a means of attachment to the animal. The packaging must provide this functionality in a hydrodynamic form to minimize the forces generated by fluid flow. These forces can remove the tag or adversely affect the behavior or energetics of the animal. Despite the recent advancements in electronics technology, sophisticated analysis and design of the packaging has been lacking. In this work, drag loading of a suction cup tag was analyzed using a computational fluid dynamical (CFD) model. The CFD model was used to analyze the forces acting on the tag over a range of flow velocities and flow orientations. The results from the analysis identified key features of the tag geometry around the suction cups that can be changed to reduce drag by up to 60% in simulation. Additionally, off-axis flow over the tag can result in a doubling of the drag force. The simulation results were validated in an experimental water tunnel. The use of computational modeling accelerates the design process because it provides access to information that might be unavailable in a purely experimental evaluation of the system. These models also enable the