Kinematics and dynamics of the auto-rotation of a model winged seed
Kinematics and dynamics of the auto-rotation of a model winged seed
复制标题
有翼种子模型自转的运动学和动力学
DOI：
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发表时间：
2018
影响因子：
3.4
通讯作者：
M. García
中科院分区：
文献类型：
--
作者：
G. Arranz;M. Moriche;Markus Uhlmann;O. Flores;M. García
对带翼种子模型自转过程进行了数值模拟。通过同时求解围绕种子的流动的Navier-Stokes方程和种子运动的刚体方程来进行计算。基于下降速度和特征弦长的雷诺数在80-240的范围内变化。在此范围内，种子达到一个渐近状态，有限振幅的自旋转，而较小的雷诺数值没有观察到自旋转。种子的运动由种子的圆锥角、俯仰角、角速度和水平平移来表征。这些数量的值是定性相似的文献中报道的实验与真实的有翼的种子。当增加雷诺数时，种子倾向于以更高的速度旋转，相对于水平面具有更小的倾斜度，并且具有更大的平移速度。对于空气动力，观察到随着雷诺数的增加，水平分量的大小减小，而垂直分量增加。沿翼展沿着的力分布的特点是使用整体和局部特征速度和弦长的无量纲化的力系数。研究发现，当采用局部尺度时，力的垂向分量不依赖于雷诺数，而弦向分量依赖于雷诺数。
Numerical simulations of the auto-rotation of a model winged seed are presented. The calculations are performed by solving simultaneously the Navier–Stokes equations for the flow surrounding the seed and the rigid-body equations for the motion of the seed. The Reynolds number based on the descent speed and a characteristic chord length is varied in the range 80–240. Within this range, the seed attains an asymptotic state with finite amplitude auto-rotation, while for smaller values of the Reynolds number no auto-rotation is observed. The motion of the seed is characterized by the coning and pitch angles, the angular velocity and the horizontal translation of the seed. The values obtained for these quantities are qualitatively similar to those reported in the literature in experiments with real winged seeds. When increasing the Reynolds number, the seed tends to rotate at higher speeds, with less inclination with respect to the horizontal plane, and with a larger translation velocity. With respect to the aerodynamic forces, it is observed that, with increasing Reynolds number, the horizontal components decrease in magnitude while the vertical component increases. The force distribution along the wing span is characterized using both global and local characteristic speeds and chord lengths for the non-dimensionalisation of the force coefficients. It is found that the vertical component does not depend on the Reynolds number when using local scaling, while the chordwise component of the force does.
DOI：
10.1016/j.ijmultiphaseflow.2013.10.010
发表时间：
2013-10
影响因子：
3.8
作者：
M. Uhlmann;J. Dušek
通讯作者：
M. Uhlmann;J. Dušek