Competitive swimming aims to achieve high performances by the only mechanical action of the swimmer in the fluid at rest. The cyclic action of the arms and legs generates a flow which, by the principle of reciprocal actions (Newton`s 3rd law) acts on the body surfaces. In this context, the hand movement is crucial. The hand propulsive forces directly depend on this flow. Study of these propulsive forces have made mostly from quasi-steady approaches (Schleihauf 1979), and results are commonly given in the form of lift (CL) and drag (CD) coefficients. Where drag force (D) is defined as the force acting parallel to the flow direction, and lift forces (L) is defined as the force acting perpendicularly to the drag force. However, the quasi-static approaches are not sufficiently accurate because the flow has a complex vortex dynamics, unsteady and turbulent. Thus more and more unsteady analyzes are carried out, relying on several unsteady effects. In this context, this paper attempts to quantify the time-dependence of aerodynamic forces for a simple yet important motion. For this purpose, a CFD analysis was carried out in order to simulate the flow around a hand in translation at a constant velocity, from an impulsive start.
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