Summary: | Underwater Undulatory Swimming (UUS) is an area of continuing development in elite swimming. The propulsive forces generated during UUS are investigated experimentally, during an over-speed tow, and numerically using Elongated Body Theory (EBT), developed initially for fish locomotion. Two-dimensional kinematic motion data (foot, shank, thigh, torso, upper arm, lower arm, and hand) at 25Hz in the sagittal plane is acquired by manual digitisation of video recorded from a stationary camera during an over-speed active tow and input into an EBT model. Thrust (T) determined from EBT and a semi-empirical passive resistance (R) is used to estimate R-T for comparison with the experimental tow line measurement. The forces predicted from EBT although significantly larger than the experimental measurement indicate that the EBT has the potential, with suitable refinement, to provide detailed insight into the hydrodynamics of UUS. Areas for further refinement are in the use of a three-dimensional correction and that higher resolution motion data for the feet are required.
|