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The geometry of swimming and pumping at low Reynolds number.

机译:低雷诺数时游泳和抽水的几何形状。

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摘要

Geometric phases are finding an important role in applied mathematics and engineering via mathematical control theory. Two striking examples are in the description of the kinematics of a self deforming body such as a satellite with robotic appendages (Shapere and Wilczek 1989, Montgomery 1990), and the swimming motions of swimming microorganisms (Shapere and Wilczek 1989). The formulation is very natural, and the geometric quantities obtained are useful for both the quantitative, and qualitative description of the dynamics.; In 1952, J. Lighthill showed that a sphere can swim at low Reynolds number by passing axially symmetric waves along its surface (Lighthill 1952). In 1971, J. Blake revisited Lighthill's model for the sphere in the context of ciliary propulsion (Blake 1971a). He also showed that an infinitely long circular cylinder can propel itself by passing axially symmetric waves down its cross section (Blake 1971b). In 1989, A. Shapere and F. Wilczek proposed a gauge theoretic model for low Reynolds number swimming that allowed for the generalization of the results of Blake and Lighthill to include the rotations and translations due to arbitrary small amplitude boundary motions of spheres and circular cylinders (Shapere and Wilczek 1989). The main tool for predicting swimming velocities in Shapere and Wilczek's model is the curvature of the Stokes connection.; In this thesis, we calculate the Stokes curvature for two biologically relevant shapes, the elliptical cylinder, and prolate spheroid. We then apply the formalism of Shapere and Wilczek (1989) to an analogous problem of transferring fluid using a deformable membrane. We define a new Stokes connection for this problem. We obtain a model for the low Reynolds number peristaltic pump, and use it to calculate pumping rates for arbitrary small amplitude pumping motions of a cylindrical tube.
机译:几何相位通过数学控制理论在应用数学和工程中发现了重要的作用。在描述自变形物体的运动学方面有两个引人注目的例子,例如带有机器人附件的人造卫星(Shapere和Wilczek 1989,Montgomery 1990)以及游泳微生物的游泳运动(Shapere和Wilczek 1989)。公式很自然,获得的几何量对于动力学的定量和定性描述都是有用的。 1952年,J。Lighthill指出,球体可以通过沿其表面传递轴对称波来以低雷诺数运动(Lighthill 1952)。 1971年,布莱克(J. Blake)在睫状推进的背景下重新审视了莱特希尔(Lighthill)的球体模型(Blake 1971a)。他还表明,无限长的圆柱体可以通过沿其横截面传递轴对称波来推动自身(Blake 1971b)。 1989年,A。Shapere和F. Wilczek提出了一种针对低雷诺数游泳的规范理论模型,该模型允许对Blake和Lighthill的结果进行归纳,以包括球体和圆柱体的任意小幅度边界运动引起的旋转和平移(Shapere and Wilczek 1989)。在Shapere和Wilczek模型中,预测游泳速度的主要工具是斯托克斯连接的曲率。在本文中,我们计算了两个生物学上相关的形状(椭圆圆柱体和长椭球体)的斯托克斯曲率。然后,我们将Shapere和Wilczek(1989)的形式主义应用于使用可变形膜传输流体的类似问题。我们为此问题定义了一个新的Stokes连接。我们获得了低雷诺数蠕动泵的模型,并用它来计算圆柱管任意小振幅泵浦运动的泵浦率。

著录项

  • 作者

    Ehlers, Kurt Merrell.;

  • 作者单位

    University of California, Santa Cruz.;

  • 授予单位 University of California, Santa Cruz.;
  • 学科 Mathematics.; Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 1995
  • 页码 58 p.
  • 总页数 58
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 数学;机械、仪表工业;
  • 关键词

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