Effect of Bulk Viscosity on High-Speed Separation

体积粘度对高速分离的影响

• 批准号: 0625015
• 负责人: Mark Cramer
• 金额: $ 20.95万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-02-15 至 2013-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0625015&HistoricalAwards=false
• 关键词: Effect; Bulk; Viscosity; Speed; Separation

The main objective of the proposed research is to determine the effect of a fundamental property of fluids, viz, the bulk viscosity, on flow separation. It will be shown that the classical theory of shock-induced separation will break down and require modification when the bulk viscosity is sufficiently large. The required modifications and limits on the classical and modified theory will be delineated. Both analytical (triple-deck) and numerical techniques will be employed.It is suggested that four problems be solved. The first two form the core of the project and will establish the breakdown of the classical triple-deck theory for supersonic and transonic freestreams. This analytical work will also serve to establish the limitations and modifications to the classical theory. Numerical solutions of the lowerdeck equations are proposed which will complete the description of the viscous- inviscid interactions. A third task is proposed which will provide general numerical solutions to the exact Navier-Stokes equations for the shockboundary layer interaction in fluids having large bulk viscosity; this task will serve as an independent verification and extension of the analytical work. As a further illustration of the effect of large bulk viscosity on separation and loss, we will adapt our Navier-Stokes code to the problem of a shock-boundary layer interaction on curved walls and blade or wing configurations; this problem will ascertain the effect on large-scale separation. The final task is to determine the conditions under which the modified interaction theory developed in the first two problems can be applied to particle-laden gases, e.g., those arising in dusty, smoky, or foggy environments.The proposed work will uncover new physical phenomena associated with a fundamental property of fluids, will stimulate further analytical, numerical and experimental work, and will help modernize the discussion of a fundamental aspect of fluid mechanics in courses, books, and research articles.The proposed study will benefit society through direct applications of the research to problems of technological and medical interest. These include applications to non-fossil fuel power systems, many of which employ large bulk viscosity fluids as working fluids. The work proposed here will enable more efficient and economical exploitation of these sources thereby relieving the nation's dependence on fossil fuels. Because even humid and/or dusty air corresponds to large bulk viscosities, the proposed work will have an impact on the design of military aircraft and helicopters, particularly those operating in desert or ship-based environments. Further aerodynamic applications include planetary probes which must inevitably operate in atmospheres primarily comprised of large bulk viscosity fluids. We also expect that the proposed research will have mid- to long-term impact on the production of nano-particles which will result in better absorption and delivery of medications such as ibuprofen.In the course of the research described here, we will train one doctoral student and will involve the participation of one undergraduate student per year. The proposed research will further advance the National Science Foundation's goal to enhance diversity in engineering. In order to ensure that these goals are met, we have allocated funds for travel to recruit at traditionally female and black colleges. Locally, we will aggressively recruit with the assistance of college-level programs such as our Center for the Enhancement of Engineering Diversity and the local chapter of the Society of Woman Engineers.The results of the research will also be disseminated through publications in top journals in the field, conferences and web sites; in addition to assisting the senior researchers in technical matters, the undergraduates will participate in the generation of such web sites.

所提出的研究的主要目的是确定流体的基本性质，即体积粘度，对流动分离的影响。结果表明，当体黏度足够大时，经典的激波分离理论就会失效，需要修正。对经典理论和修正理论所需要的修改和限制将被描述。分析（三层甲板）和数值技术将被采用。建议解决四个问题。前两个构成了项目的核心，并将建立超音速和跨音速自由流的经典三甲板理论的分解。这一分析工作也将有助于确定经典理论的局限性和修正。给出了下甲板方程的数值解，完成了对粘-无粘相互作用的描述。提出了第三项任务，即提供大体积粘度流体中激波边界层相互作用的精确Navier-Stokes方程的一般数值解；这项任务将作为分析工作的独立核查和扩展。为了进一步说明大体积粘度对分离和损失的影响，我们将使我们的Navier-Stokes代码适用于弯曲壁面和叶片或机翼结构上的激波边界层相互作用问题；这个问题将确定对大规模分离的影响。最后的任务是确定在什么条件下，在前两个问题中发展起来的修正的相互作用理论可以应用于含颗粒气体，例如，在尘土飞扬、烟雾弥漫或多雾的环境中产生的气体。这项工作将揭示与流体基本性质相关的新物理现象，将刺激进一步的分析、数值和实验工作，并将有助于在课程、书籍和研究文章中对流体力学基本方面的讨论现代化。拟议的研究将通过直接应用于技术和医学问题而造福社会。这些应用包括非化石燃料动力系统，其中许多系统使用大体积粘度流体作为工作流体。这里提出的工作将使这些资源的开发更加有效和经济，从而减轻国家对化石燃料的依赖。由于即使是潮湿和/或多尘的空气也具有较大的体积粘度，因此拟议的工作将对军用飞机和直升机的设计产生影响，特别是那些在沙漠或船舶环境中运行的飞机和直升机。进一步的空气动力学应用包括行星探测器，它必须不可避免地在主要由大体积粘度流体组成的大气中工作。我们还期望拟议的研究将对纳米颗粒的生产产生中长期影响，这将导致更好的吸收和输送诸如布洛芬之类的药物。在这里描述的研究过程中，我们将培养一名博士生，并将涉及每年一名本科生的参与。这项提议的研究将进一步推进美国国家科学基金会提高工程多样性的目标。为了确保实现这些目标，我们拨出了旅费，用于在传统的女性和黑人大学招生。在当地，我们将通过大学水平的项目，如我们的工程多样性增强中心和女工程师协会的地方分会，积极招募人才。研究结果也将通过该领域顶级期刊、会议和网站的出版物加以传播；除了协助资深研究人员处理技术问题外，本科生还将参与这些网站的制作。