Experimental and Numerical Investigation of High Speed Swimmer Motion Drag Force in Different Depths from Free Surface

In this study, the drag force exerted on swimmer body is investigated by computational fluid dynamic (CFD) and then the results validity are compared with towing tank experiments. The main target of this research is swimmer thruster power evaluation to reach the high speed motion underwater. In the last decade, the low speed swimmer motion has been studied by researchers for sport purposes and improvement of diving time record, while in this research authors have tried to increase swimmer speed up to 8 ms-1 by use of electrical thruster system. The numerical simulations have been done by computational fluid dynamics considering three dimensional two phase turbulent flow in the base of Volume of Fluid (VOF) method. The geometry of the swimmers'' bodies was generated by 3-D scanning and image modeling of real swimmers in experimental diving test. Different turbulent models could be applied in specific case but the favorable one (k– method) is selected to estimate the forces on the swimmers. The experiments were programed by five swimmers and one mannequin for different depths and speeds. The numerical simulation results showed a good agreement with the experimental output data up to 8 ms-1 but more speed test results were not accessible because of lab limitations. The results showed whatever swimmer go to deeper depths up to certain value the drag force exerted to him will be reduced. This work introduced asseveration about maximum swimmer speed test worldwide that is twice the other work heretofore.