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Computational fluid dynamics vs. inverse dynamics methods to determine passive drag in two breaststroke glide
L Costa1, V R Mantha2, A J Silva3
1Centre of Research, Education, Innovation and Intervention in Sports (CIFI2D), Faculty of Sport, University of Porto, Porto, Portugal; Porto Biomechanics Laboratory (LABIOMEP) University of Porto, Porto, Portugal.
Journal of Biomechanics
|June 20, 2015
Summary
Computational fluid dynamics (CFD) simulations underestimated drag and drag coefficient in breaststroke gliding positions compared to experimental data. Accurate CFD requires individualized swimmer models and precise kinematic data for reliable results.
Area of Science:
- Sports Science
- Fluid Dynamics
- Biomechanical Engineering
Background:
- Computational fluid dynamics (CFD) is crucial for analyzing water movement and drag around swimmers.
- Understanding these forces is key to improving swimming performance.
Purpose of the Study:
- To compare drag and drag coefficient (CD) values from experimental measurements and CFD simulations.
- To investigate flow effects around swimmers in two distinct breaststroke gliding positions (GP1 and GP2).
Main Methods:
- Six male breaststroke swimmers performed experimental tests using cable velocimetry.
- A 3D swimmer model was created for CFD simulations using the standard k-ε turbulent model.
- CFD and experimental data were compared for velocities ranging from 1.10 to 1.70 m/s.
Main Results:
- CFD generally yielded lower drag and CD values than experimental results for both GP1 and GP2.
- Both methods showed a similar trend of increasing/decreasing drag with velocity, except for GP2 CD.
- CFD and experimental CD values for GP2 exhibited opposing tendencies with velocity changes.
Conclusions:
- CFD results using generic models should be interpreted cautiously due to variations in body shape and dimensions.
- Individualized 3D swimmer models and accurate kinematic data are essential for enhancing CFD accuracy in swimming research.
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