Appropriateness of three fish species (Scomber scombrus, Sarda sarda, and Thunnus thynnus) from the Scombridae family in terms of shape and hydromechanics in designing the body of a robotic fish

In this study, we first identify seven criteria for the design of biomimetic robotic fish and focus on two of these tasks: shape and hydromechanics. For this purpose, fish body part measurements were obtained using previous work and also captured and harvested fish samples to construct computer-aided design (CAD) models of three fish species: Scomber scombrus, Sarda sarda, and Thunnus thynnus. Dead body drag and caudal fin flapping were considered as two separate problems. Computational simulations were carried out to determine drag and pro-pulsive performance. Body drag simulations showed that the Reynolds dependence of the drag coefficient of three different species can be adequately expressed by a single laminar scaling correlation. At the same length and swimming speed, the Atlantic mackerel experiences the least drag. Caudal fin deformation simulations showed that the Atlantic bluefin tuna offers the highest thrust and efficiency. Peak efficiency is in the range of 31-35 percent observed at the same optimal Strouhal number, St = 0.5, for all species. It is shown that the aspect ratio as the main length scale influences propulsion performance.
National Center for High-Performance Computing of Turkey (UHeM) [1007782020]
The authors thank Dr. Ali Ulas from Ege University, Dr. Ahmet Onal for helping to photograph fish sections, and, Ercan Er, a commercial diver, for providing bluefin tuna caudal fins. Thanks are also due to Erdem Kaya for supporting HPC runs. The computing resources used in this work were provided by the National Center for High-Performance Computing of Turkey (UHeM) under grant number 1007782020.