Berger M A, de Groot G, Hollander A P
Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
J Biomech. 1995 Feb;28(2):125-33. doi: 10.1016/0021-9290(94)00053-7.
Forces acting on the forearm and hand during swimming can be decomposed into drag forces and lift forces. In this study drag and lift forces were measured on two models of a human hand and forearm when towed in a towing tank. To compare the results of models with different size at different velocities force data were normalized to drag and lift coefficients (Cd and Ct). Influence of the orientation of the model with respect to the flow, velocity, size of the model and the relative contribution of the hand and forearm on Cd and Ct were studied. The orientation of the model with respect to the line of motion was varied by rotating the models around three axes, and quantified using the angle of pitch (AP: the angle between the hand plane and flow) and the sweep-back angle (SB: the orientation of the flow vector when projected on the hand plane). Cd was maximal when the palm of the hand is almost perpendicular to the flow (AP = 65 degrees, SB = 342 degrees). Ct shows maximal values at two different orientations: with the hand in a thumb-leading position, AP = 31 degrees, SB = 358 degrees, and with the hand in a little finger-leading position, AP = 48 degrees, SB = 193 degrees. The orientation of the hand was very critical in generating lift forces. By contrast, the influence of velocity and size of the model on the values of Cd and Ct was limited.(ABSTRACT TRUNCATED AT 250 WORDS)
游泳时作用在前臂和手部的力可分解为阻力和升力。在本研究中，当在拖曳水池中拖曳时，对两种人手和前臂模型的阻力和升力进行了测量。为了比较不同尺寸模型在不同速度下的结果，将力数据归一化为阻力系数和升力系数（Cd和Ct）。研究了模型相对于水流的方向、速度、模型尺寸以及手部和前臂的相对贡献对Cd和Ct的影响。通过绕三个轴旋转模型来改变模型相对于运动方向的方向，并使用俯仰角（AP：手部平面与水流之间的夹角）和后掠角（SB：水流矢量投影到手部平面时的方向）进行量化。当手掌几乎垂直于水流时（AP = 65度，SB = 342度），Cd最大。Ct在两个不同方向上显示最大值：手部处于拇指领先位置时，AP = 31度，SB = 358度；手部处于小指领先位置时，AP = 48度，SB = 193度。手部的方向在产生升力方面非常关键。相比之下，模型的速度和尺寸对Cd和Ct值的影响有限。（摘要截短于250字）
