Meeting Abstract
Thunniform swimming has been recognized as an efficient swimming type for high-speed travelers such as tuna. When tuna swims, the majority of motion happens at posterior one-third of the body, which mainly consists of flexible caudal fin and peduncle with rotational freedom. It has been proven that choosing the optimal flexibility for flapping aerofoil panel or artificial fin can boost the thrust and efficiency by over 100%, due to change in fin kinematics and wake structure. In this study, a free-swimming flow tank set-up will be employed to investigate whether there also exists an optimal peduncle flexibility in terms of swimming performance. An artificial tuna tail with same rigid caudal fin (as the control variable) and peduncles with various rotational stiffness will be tested over a range of frequency (0.5-2.5 Hz) at constant angle amplitude (30 degrees). Steady swimming speed and torque input will be measured for evaluating thrust generation and cost of transportation. The steady swimming states will also be video recorded for kinematic analysis and study of fluid-structure interaction.
