Numerical study of high-Reynolds number vortex flows with high-order accurate meshless vortex method.

高阶精确无网格涡流法对高雷诺数涡流的数值研究

基本信息

批准号：
EP/E033083/1
负责人：
Lorena Barba
金额：
$ 26.66万
依托单位：
University of Bristol
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2007
资助国家：
英国
起止时间：
2007 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FE033083%2F1
关键词：
Numerical study Reynolds number vortex

项目摘要

The flow of fluids is an unusually difficult subject to study, but it affects innumerable aspects of our life. The understanding of the flow of blood in the heart, the vortices created by jet airliners, the cooling of a laptop's microchip, and the flow of air in the atmosphere and water in the ocean, all of these require knowledge of fluid dynamics. Fluid dynamics is a very challenging and exciting field of science. The applications are countless, and so are the complexities. Because the general physical description of fluids results in a mathematical formulation --a differential equation-- which cannot in general be solved, scientists have attempted to use computer simulations since these were available. In fact, many advances in computational science are a direct result of the efforts to tackle some problem of fluid flow.Some flows are particularly difficult to solve, even with the most powerful computers. Flows involving eddies of multiple sizes, turbulence or rapid changes are the chief example. But vortices appear almost everywhere in fluids, and they are responsible for many phenomena that we would like to understand or control. For example, when we hear the noise of a helicopter, that noise is in great measure produced by the vortices left behind by one blade being hit by the next oncoming blade. And when airplanes are spaced by the control tower on approach to landing, it is mostly due to the need to avoid the vortices left behind by the previous plane landing. If our understanding of airplane vortices was such that we could predict where they are in a given moment, the instructions for the next oncoming plane could be safely given with airport efficiency in mind. A huge amount of money could be saved by increasing the frequency of landings in this way.To study these types of problems, the computational approach is essential. The field of Computational Fluid Dynamics involves computer simulations of problems of fluid flow. In this field, the majority of scientists use methods which are based on dividing the space where there is fluid into small elements, squares or triangles, or cubes, where the equations are said to be discretised. The equations are solved by, for example, keeping track of how much fluid enters one side, and leaves the other side, of the elements. These methods have been used for decades, and can produce excellent results. But many times they suffer from one problem: they diffuse the vortices too fast. Using again the example of the jet airliner, they would predict that the wake vortices are gone, when in fact they still persist and pose a danger to oncoming airplanes.Some computational scientists have been experimenting with different methods, where instead of using geometrical elements of fluid, a set of disconnected points are used to calculate the quantities of interest, like velocity. This field has come to be known as meshless or gridfree computation. The research of Dr Barba concentrates in this field, where the use of points, or fluid particles, results in calculations which are able to resolve the small eddies in the flows, and do not diffuse them too fast. The methods are in constant development, and recent advances mean that there is opportunity for very accurate simulations. The research programme of Barba aims to develop an advanced method, based on vortex particles, which is highly accurate. She will introduce innovations allowing the calculation of a range of scales in the flow, more efficiently, and develop clever ways of accounting for the presence of bodies immersed in the fluid. These advances promise to have a significant impact in the field of meshless computation. Moreover, she will use the new methods to study specific problems of interest to physical oceanographers and aerodynamicists, involving interaction of vortices. The results of this research will make progress in both vortex dynamics and computational science in general.

流体的流动是一个异常困难的研究，但它会影响我们生活中无数的方面。对心脏中血流的理解，喷气客机产生的涡流，笔记本电脑的微芯片的冷却以及大气和海洋中的空气流动，所有这些都需要了解流体动力学。流体动力学是一个非常具有挑战性和令人兴奋的科学领域。应用程序是无数的，复杂性也是如此。由于流体的一般物理描述会导致数学公式 - 一个差分方程 - 通常无法解决，因此科学家试图使用计算机模拟，因为这些方程可用。实际上，计算科学的许多进步是解决一些流体流动问题的直接结果。即使使用最强大的计算机，某些流也很难解决。涉及多种尺寸，湍流或快速变化的涡流的流是主要的例子。但是涡流几乎在流体中出现，它们是我们想理解或控制的许多现象的原因。例如，当我们听到直升机的噪音时，这种噪音在很大程度上是由于一个刀片被下一个即将来临的刀片击中的涡流产生的。而且，当飞机被控制塔间隔时，在着陆接近时，这主要是由于需要避免以前的飞机降落留下的涡流。如果我们对飞机涡流的理解使我们可以在给定的时刻预测它们的位置，那么可以牢记机场效率的情况下，可以安全地给出下一架飞机的说明。通过以这种方式增加着陆频率可以节省大量资金。要研究这些类型的问题，计算方法至关重要。计算流体动力学领域涉及计算机流动问题的计算机模拟。在这一领域，大多数科学家使用的方法基于将流体分为小元素，正方形或三角形或立方体的空间，在该空间中，据说方程式被认为是离散的。例如，通过例如跟踪流体进入一侧，并离开另一侧的元素来求解。这些方法已经使用了数十年，可以产生出色的结果。但是很多时候他们遇到了一个问题：它们太快地扩散了涡流。他们再次以喷气客机的示例来预测尾流涡旋已经消失了，实际上它们仍然持续存在并构成危险的危险。一些计算科学家一直在尝试不同的方法，而不是使用流体的几何元素，而是使用一组脱节的点来计算类似的velocity的数量。该领域已被称为无网状或无网状计算。 BARBA博士集中在该领域的研究，在该领域，使用点或流体颗粒的使用导致计算能够解决流动中的小涡流，并且不会太快地扩散它们。这些方法正在持续发展，最近的进步意味着有机会进行非常准确的模拟机会。 BARBA的研究计划旨在基于高度准确的涡流粒子开发高级方法。她将引入创新，允许更有效地计算流量中的一系列量表，并开发出巧妙的方式来计算浸入液体中的身体的存在。这些进步有望在无网络计算领域产生重大影响。此外，她将使用新方法来研究物理海洋学家和空气动力学家感兴趣的特定问题，涉及涡流的相互作用。这项研究的结果将在涡流动力学和一般计算科学方面取得进展。