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Hydrodynamic drag and lift forces on human hand/arm models
M A Berger1, G de Groot, A P Hollander
1Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
Journal of Biomechanics
|February 1, 1995
Summary
Understanding swimming biomechanics requires analyzing forces on the hand and forearm. Optimal hand orientation significantly impacts lift and drag coefficients, crucial for swimming efficiency.
Area of Science:
- Biomechanics
- Fluid Dynamics
- Sports Science
Background:
- Swimming involves complex forces on the forearm and hand, including drag and lift.
- Quantifying these forces is essential for improving swimming technique and performance.
Purpose of the Study:
- To measure drag and lift forces on human hand and forearm models.
- To determine the influence of model orientation, velocity, and size on drag and lift coefficients.
- To identify optimal hand and forearm orientations for generating lift and minimizing drag.
Main Methods:
- Two human hand and forearm models were towed in a towing tank.
- Forces were measured and normalized to drag (Cd) and lift (Ct) coefficients.
- Model orientation was varied using pitch angle (AP) and sweep-back angle (SB).
Main Results:
- Maximum drag (Cd) occurred when the palm was nearly perpendicular to the flow (AP = 65°, SB = 342°).
- Maximum lift (Ct) was achieved in thumb-leading (AP = 31°, SB = 358°) and little finger-leading (AP = 48°, SB = 193°) positions.
- Hand orientation critically influenced lift generation; velocity and model size had limited impact on Cd and Ct.
Conclusions:
- Hand and forearm orientation is a critical factor in modulating hydrodynamic forces during swimming.
- Specific orientations maximize lift, which is essential for propulsion, while others maximize drag.
- These findings provide valuable insights for optimizing swimming strokes and training methodologies.