Optimal Caudal Fin Kinematics at moderate Re numbers

We investigate the optimality of caudal fin kinematics inspired by certain fish species such as tuna. We consider caudal fin moves that are out of phase with the anterior section of the body. We investigate the benefits of spatially discontinuous fin-kinematics at moderate Re, by coupling three-dimensional simulations of fish-like swimmers with the Covariance Matrix Adaptation (CMAES) optimization algorithm. The optimization suggests kinematics similar to those observed in natural swimmers at higher Re numbers. At moderate Re, optimal kinematics lead to improved performance with regard to both the peak and average swimming power. However, a similar advantage is not observed for fish swimming at low Re, where a continuous sinusoidal wave is found to be preferable.