Latitudinally deforming rotating sphere
Latitudinally deforming rotating sphere
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DOI：
10.1016/j.apm.2019.01.016
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发表时间：
2019-07-01
影响因子：
5
通讯作者：
Turkyilmazoglu, M.
中科院分区：
文献类型：
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作者：
Turkyilmazoglu, M.
在这项研究中，我们考虑了一个球的表面是完全覆盖的可拉伸的弹性材料，球的半径是固定的，它也是围绕其径向轴旋转。我们调查如何触发流体流的轴对称运动的球体周围的影响，同时存在的球体旋转和纬度拉伸。考虑到在球体上的变形开始于极点，该问题被配制成使得极点附近的流体流动类似于由于线性可拉伸旋转盘引起的诱导流，这在以前的研究中已经被很好地描述。当省略旋转时，流动在纯拉伸的作用下以二维方式发展;否则，会出现三维轴对称流体流动，该流动在每个纬度角处进行数值计算并使用扰动方法进行计算。考虑壁面变形的解与传统的球转动解的性质不同。这个解决方案，然后用于计算由于物理阻力和扭矩作用在球体上的表面剪切。壁面拉伸的贡献减小了阻力，而高旋转抑制了拉伸的影响以增强阻力。当拉伸和旋转机制都在起作用时，需要更大的扭矩来旋转球体。(C)2019爱思唯尔公司All rights reserved.
In this study, we consider a sphere with a surface that is fully covered by a stretchable elastic material, The radius of the sphere is fixed and it is also rotating about its radial axis. We investigate how the axisymmetric motion of a triggered fluid flow around the sphere is affected by the presence of both sphere rotation and latitudinal stretching. Considering that the deformation over the sphere commences at the pole, the problem is formulated such that the fluid flow near the pole is similar to the induced flow due to a linearly stretchable rotating disk, which has been described well in previous studies. When the rotation is omitted, the flow develops two-dimensionally under the action of pure stretching; otherwise, a three-dimensional axisymmetric fluid flow occurs, which is computed at each latitudinal angle both numerically and using a perturbation approach. The solution with wall deformation is different from the traditional character of the solution due to a solely rotating sphere. This solution is then used to compute the surface shears due to the physical drag and torque acting over the sphere. The contribution of wall stretching reduces the drag, whereas high rotation suppresses the effects of stretching to enhance the drag. More torque is required to rotate the sphere when both stretching and rotation mechanisms are in action. (C) 2019 Elsevier Inc. All rights reserved.