Assessment of passive drag in swimming by numerical simulation and analytical procedure |
| |
| Authors: | Tiago M Barbosa Rui Ramos António J Silva Daniel A Marinho |
| |
| Institution: | 1. Physical Education &2. Sports Science Academic Group, National Institute of Education, Nanyang Technological University, Singapore;3. Research Centre in Sports, Health and Human Development, Vila Real, Portugal;4. Department of Sport Sciences, Polytechnic Institute of Bragan?a, Bragan?a, Portugaltiago.barbosa@nie.edu.sg;6. Research Centre in Sports, Health and Human Development, Vila Real, Portugal;7. Department of Sport Sciences, University of Beira Interior, Covilha, Portugal;8. Department of Sport Sciences, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal |
| |
| Abstract: | The aim was to compare the passive drag-gliding underwater by a numerical simulation and an analytical procedure. An Olympic swimmer was scanned by computer tomography and modelled gliding at a 0.75-m depth in the streamlined position. Steady-state computer fluid dynamics (CFD) analyses were performed on Fluent. A set of analytical procedures was selected concurrently. Friction drag (Df), pressure drag (Dpr), total passive drag force (Df+pr) and drag coefficient (CD) were computed between 1.3 and 2.5 m · s?1 by both techniques. Df+pr ranged from 45.44 to 144.06 N with CFD, from 46.03 to 167.06 N with the analytical procedure (differences: from 1.28% to 13.77%). CD ranged between 0.698 and 0.622 by CFD, 0.657 and 0.644 by analytical procedures (differences: 0.40–6.30%). Linear regression models showed a very high association for Df+pr plotted in absolute values (R2 = 0.98) and after log–log transformation (R2 = 0.99). The CD also obtained a very high adjustment for both absolute (R2 = 0.97) and log–log plots (R2 = 0.97). The bias for the Df+pr was 8.37 N and 0.076 N after logarithmic transformation. Df represented between 15.97% and 18.82% of the Df+pr by the CFD, 14.66% and 16.21% by the analytical procedures. Therefore, despite the bias, analytical procedures offer a feasible way of gathering insight on one’s hydrodynamics characteristics. |
| |
| Keywords: | Swimming gliding drag coefficient friction drag pressure drag |
|
|
