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Study on Numerical Methods for Flows with Moving Boundaries

动边界流数值方法研究

基本信息

批准号：
12650894
负责人：
TAKAKURA Yoko
金额：
$ 2.37万
依托单位：
Tokyo University of Agriculture and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

As governing equations for numerical methods of flows with moving boundaries, usually used are the conservative form in general coordinate system in the case of compressible fluid, and the ALE (Arbitrary Lagrangian-Eulerian) form in the case of incompressible fluid, but these methods have the difficulty to re-generate grids at each time step when the boundaries are moving. On the other hand, the moving-coordinate method that the head investigator proposed is to resolve the difficulty. The purposes of this research project covers two intent : one is to give the unified derivation to the governing equations for numerical methods of flows with moving boundaries, which have existed individually, and give the scientific prospect to the field ; the other is to extend the ALE method and the moving-coordinate method for general use, apply them to physical and engineering problems, and enable to solve problems which cannot be solved because of the difficulty above statedIn the fiscal year of 20 … More 00, it was shown that the governing equations for numerical methods including moving boundaries, i.e., the conservative form in general coordinate system, the ALE (Arbitrary Lagrangian-Eulerian) form, and the moving-coordinate form, are derived unifiedly in this order, and simultaneously the meaning of the geometric conservation laws which metrics should satisfy was analytically 〓〓rified. Furthermore the moving-coordinate method was extended for general use, and applied to two cases with each way and flows : a 〓〓lti-domain problem for unsteady flows about a flying projectile launched in a ballistic range and a single-domain problem with cut-cell method for branch flows in opening process of a high-voltage gas circuit breaker. As results, it has been confirmed that the moving-coordinate method works effectively.In the fiscal year of 2001, the ALE form was extended to the general coordinate system, and applied to gun-tunnel flows. In the numerical computation there are two courses : to simulate complicated flows closer to real phenomena and obtain detail, and to model (simplify) and obtain practical information with less computing time. As an example of the latter course, the quasi-one-dimensional Euler equations including the change of cross area with not only space but also time were derived, the ALE method was correctly applied with modelling of the piston motion and the pressure loss. Through comparison with experiments, it has been confirmed that the extended ALE method works well.In the fiscal year 2002, the results obtained till then were published in international Journals with evaluation and consideration added. As preparatory stage to future developments, unstructured-grid solvers for arbitrary configuration and high-accurate schemes including source terms have been developed Less

对于动边界流动数值方法的控制方程，可压缩流体通常采用一般坐标系下的守恒型，不可压缩流体通常采用ALE（Arbitrary Lagrangian-Eulerian）型，但这些方法在边界移动时，存在网格重构的困难。另一方面，课题组组长提出的移动坐标法就是为了解决这一难题。本课题的研究目的有两个：一是对已有的动边界流动数值方法的控制方程进行统一推导，并对该领域的研究进行科学的前景展望;二是将ALE方法和移动坐标方法推广到一般的应用中，将它们应用到物理和工程问题中，2000年财政年度， ...更多信息 00，它表明，控制方程的数值方法，包括移动边界，即，按此顺序统一导出了一般坐标系下的守恒形式、ALE（Arbitrary Lagrangian-Eulerian）形式和动坐标形式，同时解析地阐明了度量应满足的几何守恒律的意义.进一步将移动坐标法推广到一般情况下，并分别应用于弹道导弹发射场飞行弹丸非定常流场的单域问题和高压气体断路器分闸过程中分支流场的单域割元法问题。2001年，ALE格式被推广到一般坐标系，并应用于炮管流场。在数值计算过程中，有两个过程：一是模拟复杂的流动，使之更接近真实的现象，获得细节;二是模型化（简化），以较少的计算时间获得实际信息。作为后一过程的一个例子，导出了准一维欧拉方程，方程中不仅考虑了截面积随时间的变化，而且考虑了截面积随空间的变化，正确地应用了ALE方法，建立了活塞运动和压力损失的模型。通过与实验结果的比较，证实了扩展ALE方法的有效性，并于2002年在国际期刊上发表了该方法的研究成果，同时还对该方法进行了评价。作为未来发展的准备阶段，已经开发了任意配置的非结构网格求解器和包括源项的高精度格式。