Development of numerical and experimental methods for resolving of concentrated vortex structures

涡结构的求解是计算流体力学的主要问题之一。该项目的总体目标是开发能够探测更大范围涡旋尺度的数值技术。在该项目中，采取了两项战略。一种是基于涡量约束（VC）方法的发展，而另一种是基于一个新的概念，结合基于网格的有限体积法（FVM）与网格自由涡方法（CVM）。这两种策略的目的是减少目前在所有现有的数值方法的数值扩散量。作为涡量约束方法的一部分，在动量方程中引入了一个可以对抗数值扩散的附加项。该项将根据无网格涡流法（CVM）计算。在混合FVM-CVM方法中，涡被分为大尺度和小尺度结构，其中前者然后用FVM建模，后者用CVM建模。这两种方法都将使用文献中现有的机翼后翼尖涡流的实验结果进行验证。涡结构识别算法的联合开发，它们在FVM OpenFoam中的实现，以及它们对相同测试用例的验证，以及将CVM结果集成到VC方法中，表明项目的这两个部分是紧密相连的，所开发的方法可用于广泛的流体力学基础和相关问题。

The resolving of vortex structures is one of the main problems in computational fluid dynamics. The overall objective of this project is to develop numerical technologies that can detect a wider range of vortex scales. In the project, two strategies are pursued. One is based on the development of the vorticity confinement (VC) method, while the other is based on a new concept that combines the grid-based finite volume method (FVM) with the grid-free vortex method (CVM). Both strategies aim to reduce the amount of numerical diffusion present in all existing numerical methods. As part of the vorticity confinement method, an additional term that can act against numerical diffusion is introduced into the momentum equation. This term will be calculated based on the grid-free vortex method (CVM). In the hybrid FVM-CVM method, the vortices are divided into large-scale and small-scale structures, where the former is then modelled with FVM and the latter with CVM. Both of these methods will be validated using in the literature available experimental results for tip vortex flow behind wings. The joint development of vortex structure identification algorithms, their implementation in FVM OpenFoam and their validation of the same test cases as well as the integration of CVM results in the VC-method show that these the both parts of the project are strongly interconnected, and the developed methods can be used for a wide range of fundamental and related problems in fluid mechanics.