On the Development of a Novel Approach in Modelling of Turbulent Pulsating Flows

在许多工程系统或自然环境中，都会出现散流或自由流速度随时间变化的非恒定流。在许多最近的出版物中强调了它们的应用和挑战的例子包括：i)颈动脉和冠状动脉中的脉动血流，例如，在观察到大多数动脉粥样硬化的地方；ii)核电站在各种假设故障条件下的瞬时事件是对核电站运行施加严格限制的最脆弱的条件。该项目将建立一种研究脉动流动的新方法，这将从根本上改变人们对非定常湍流的认识，从而从根本上改进以下方面：a)对脉动流动的理解；b)使用湍流模型模拟非定常流动；b)湍流控制以及非定常摩擦模型的建立方式。这将导致以下方面的改进：血液周期性瞬变流动的预测能力；利用脉动流动的减阻；核反应堆的安全性和经济性；涡轮机和风力涡轮机的效率；水资源效率和海岸保护。此外，这些项目将产生一个高保真、高可伸缩性的内部CFD(计算流体动力学)程序包，这将支持未来的合作。将进行全面的数值模拟计划，以研究在广泛的脉动参数和雷诺数范围内的流动。将使用内部的直接数值模拟(直接数值模拟)/大涡模拟(LES)程序包来研究详细的流动结构和流动的湍流统计。与动脉搏动血流有关的病例的结果将与布里斯托尔大学翻译生物医学研究中心提供的实验数据进行分析，该中心将作为该研究的项目合作伙伴。

Unsteady flows in which the bulk or free-stream velocity varies with time arise in many engineering systems / natural environment. Examples of applications and the challenges that they pose are highlighted in numerous recent publications include: i) The pulsatile blood flows in carotid and coronary arteries, for example, where a majority of atherosclerosis is observed; ii) The transient events at a nuclear power plant during various hypothetical fault conditions are the most vulnerable conditions which impose severe constraints on plant operations. The project will establish a new approach in study pulsating flow which will fundamentally change how unsteady turbulent flow is perceived leading to fundamental improvements in: a) understanding of pulsating flows; b) simulations of unsteady flows using turbulence modelling, b) turbulent flow control and the way that the unsteady friction models are formulated. This will result in improved: predictive capability of a blood periodic transient flow; drag reduction that utilises pulsating flows, safety and economy of nuclear reactors; efficiency of turbomachinery and wind turbines, water resources efficiency and protection of coasts. Moreover, the projects will result a high-fidelity, high-scalability in-house CFD (Computational Fluid Dynamics) package which will support future collaborations.A comprehensive programme of numerical simulations will be conducted to study the flow at wide range of pulsating parameters and Reynolds numbers. An in-house DNS (direct numerical simulations) / LES (large eddy simulations) package will be used to investigate detailed flow structure and turbulence statistics for the flow. Results of the cases associated with pulsatile blood flows in arteries, will be analysed against experimental data provided by the Translational Biomedical Research Centre, University of Bristol, who will act as the project partner to the research.