Numerical and Experimental Studies of Transition in Three-Dimensional Boundary Layers

三维边界层转变的数值和实验研究

• 批准号: 8617897
• 负责人: Alan Faller
• 金额: $ 15万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-08-01 至 1990-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8617897&HistoricalAwards=false
• 关键词: Numerical; Experimental; Studies; Transition; Three

Support is provided for a combined numerical (super-computer) and experimental study of instability and transition to turbulence in the KEB class of 3-d boundary layers; the vonKarman-Ekman-Bodewadt layers. In particular, we emphasize the roll of free-stream disturbances and the excitation of the Type II instability, which has received little or no attention in previopus studies, and the different routes to transition dependent upon the relative amplitudes of the Type I and Type II unstable vortices that are known to occur in thes layers. These studies should be viewed as generic research, i.e. having application to a wide variety of problems that occur throughout mechanical, chemical, and civil and aerospace engineering. The results of a successful program of research will provide the background information for understanding transition to turbulence in a broad class of 3-d boundary layers. Three-dimensional boundary layers occur over swept-back airfoils, in the flow over and around vehicles of all sorts, in rotating machinery (fans, pumps, turbines, etc.), on the noses of rotating projectiles, incurved pipes, river bends, and planetary boundary layers. Transitition to turbulenace in these layers is important in enginerring design because it affects stresses, vibrations, nois, lift, heat transfer, ablation, etc.

支持一个组合的数字（超级计算机）和 不稳定性和向湍流转捩的实验研究 三维边界层的KEB类; vonKarman-Ekman-Bodewadt层。 特别地，我们强调自由流扰动的滚动和 II型不稳定性的激发，这已经收到很少或没有 注意在previopus研究，和不同的路线， 过渡依赖于I型和I型的相对振幅 不稳定的旋涡，已知发生在这些层。这些 研究应被视为一般性研究，即 适用于各种各样的问题，发生在整个 机械、化学、民用和航空航天工程。 结果 一个成功的研究项目将提供背景 在一个广泛的类中理解过渡到湍流的信息 三维边界层。 三维边界层出现在 后掠翼型，在各种飞行器的上方和周围的气流中， 在旋转机械（风扇、泵、涡轮机等）中，在...鼻子底下 旋转的抛射体、弯曲的管道、河流弯曲和行星 边界层 在这些层中， 在工程设计中很重要，因为它影响应力， 振动、噪音、升力、传热、烧蚀等。