复杂流场中单纤维动力学计算的一种新算法

A NEW METHOD TO SIMULATE THE DYNAMICS OF SINGLE FIBER IN COMPLEX FLOW FIELDS

  • 摘要: 悬浮液中纤维的运动和旋转行为在许多现代工业领域都非常重要. Jeffery解析得到了牛顿流中椭球型纤维的动力学演化方程,但方程只有在平面简单剪切和拉伸流的条件下才有解析解. 采用数值求解时,由于方程中\cot \theta 的存在会出现奇异性.采用随体坐标的方法,消除了方程的奇异性,算法的有效性通过与解析解的比较得到了验证,并为复杂流场下纤维的动力学数值计算提供了一个可行的方法.

     

    Abstract: The translational and rotational dynamics of fiberssuspended in a fluid medium are important in many different fields of modemtechnology. Jeffery derived an equation of motion for a single rigidellipsoidal particle suspended in Newtonian fluids. Unfortunately, theanalytical solutions of Jeffery equation could only be obtained in a simpleplanar shear flow and a planar elongational flow. The main difficulty in the numerical treatment of Jeffery equation is the singularity dueto the term \cot \theta . In this paper, a co-rotational coordinate systemis proposed, which can completely eliminates this singularity. The validityof the proposed scheme is shown by a comparison between numericalresults and the analytical solution. New algorithm can easily beextended to simulatethe dynamics of single fiber in complex flow fields.

     

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