Catastrophic events in separated flow theory.

分离流理论中的灾难性事件。

• 批准号: EP/D050847/1
• 负责人: Jitesh Gajjar
• 金额: $ 28.44万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FD050847%2F1
• 关键词: Catastrophic; events; separated; flow; theory.

The study of flow separation from the surface of a solid body, and thedetermination of global changes in the flow field that develop as a result of the separation, are among the most fundamental and difficult problems of fluid dynamics. Separation not only alters the form of trajectories of fluid particles around the body, but also leads to a significant change in the values of the aerodynamic forces acting on the body.The behaviour of separated flow is quite complicated. For example, when a thin aerofoil is placed in subsonic flow, and the angle of attack is gradually increased, the separation is first observed at the leading edge of the aerofoil. It manifests itself through the formation of a small bubble of reversed flow near the leading edge. Catastrophic separation arises when for increased angles of attack, or changes in geometry, the bubble suddenly bursts and is replaced by a massive separation region covering almost the whole aerofoil. This causes drastic changes to aerodynamic properties such as lift and drag.The proposed research is aimed at furthering our understanding of separated flows. The emphasis will be on ``blow-up'' phenomena and post-catastrophic behaviour of separated flows. We intend to show that there is a relationship between these phenomena and nonlinear instability of separated flows.

研究流体从固体表面的分离，以及确定由于分离而产生的流场的整体变化，是流体动力学中最基本和最困难的问题之一。分离不仅改变了流体质点绕物体的运动轨迹，而且使作用在物体上的气动力值发生显著变化，分离流动的特性十分复杂。例如，当薄翼型置于亚音速流中，并且迎角逐渐增加时，首先在翼型的前缘处观察到分离。它通过在前缘附近形成反向流动的小气泡而显现出来。当迎角增大或几何形状改变时，气泡突然破裂，并被几乎覆盖整个翼型的大规模分离区所取代，这时就会出现灾难性分离。这会导致升力和阻力等空气动力学特性发生剧烈变化。拟议的研究旨在加深我们对分离流的理解。重点将放在分离流的“爆炸”现象和灾难后行为。我们打算表明，这些现象和分离流的非线性不稳定性之间存在着联系。

项目成果

Global stability of separated flows: subsonic flow past corners Global stability of separated flows

分离流的全局稳定性：经过拐角的亚音速流 分离流的全局稳定性

• DOI: 10.1007/s00162-010-0198-2
• 发表时间: 2010
• 期刊: Theoretical and Computational Fluid Dynamics
• 影响因子: 3.4
• 作者: Logue R