Boundary Layer Turbulence Control via Acoustically Resonating Porous Surfaces

通过声学共振多孔表面进行边界层湍流控制

• 批准号: 1706474
• 负责人: Carlo Scalo
• 金额: $ 44.98万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1706474&HistoricalAwards=false
• 关键词: Boundary; Layer; Turbulence; Control; via

Porous surfaces are ubiquitous in aeronautical applications, some of which include: suppression of noise in gas turbines; control of flow instabilities in combustion chambers; enhancement of aerodynamic performance of wings under high-lift configurations, e.g. during landing; turbine blade temperature control via coolant air bleeding through the pores; reduction of aerodynamic heating on the surface of hypersonic (Mach7) vehicles. At the core of all of the aforementioned applications there is the interaction between: (a) the flow evolving over the porous surfaces and (b) the flow trapped within the pore-space of the surfaces themselves. State-of-the-art modeling techniques are unable to simulate the physics under these combined effects. As a result, technological development in flow control over porous surfaces has been limited by the lack of progress in the modeling, and hence understanding, of the fundamental interaction between the features of the porous surfaces and overlying flow dynamics. The goal of the proposed study is to carry out highly controlled experiments and simulations in a canonical flow configuration that will allow direct comparison between the two approaches, assisting in overcoming the aforementioned limitations. The proposed research will have broader impacts on society through direct effects on engineering practice. Development of resonating surfaces will have important technological impacts in aeronautical applications, including delaying separation in high-speed boundary layers and control of trailing edge noise in commercial aircrafts. The majority of fluid machinery applications will also be impacted by the success of this effort, for it provides simple means to enhance turbulent heat-and-mass-transfer and mixing. In addition, this project will work with successful diversity and outreach programs at Purdue, including recruiting initiatives and retention of underrepresented groups with which the PIs collaborate. Porous surfaces interacting with a compressible flow are classically modeled via impedance boundary conditions. The latter are formulated directly in frequency domain, relating the Fourier transforms of the pressure and wall-normal transpiration velocity at the surface. Recent computational advances have allowed for the first time to impose impedance in the time-domain in a fully compressible Navier-Stokes solver by retaining full numerical and physical realizability (respecting causality of wave-propagation), unlocking the key computational strategy needed to unravel the fundamental physics of the coupling between a compressible flow and porous surfaces. This enabling capability provides an original and elegant way to computationally model the effect of porous surfaces on the overlying flow structure. This has allowed the first high-fidelity numerical simulation of a compressible turbulent flow over wall-impedance to be carried out, revealing the fundamental structure a new self-sustaining state of near-wall turbulence altered by acoustic resonance. The proposed work will investigate sound-turbulence interactions by controlling the acoustic impedance at the wall in the canonical setting of turbulent channel flow turbulence at flow conditions reproducible both experimentally and numerically. The proposed effort combines highly-parallel large-eddy simulations with state-of-the-art experiments, which include time-resolved tomographic and highly resolved planar particle-image velocimetry (PIV), with direct estimates of turbulent characteristics and measurement uncertainty. An experimental prototype of a tunable resonating surface will be developed and will be employed to physically demonstrate the feasibility of this process. A new series of numerical investigations will proceed in parallel, supporting analysis and modeling of wave-turbulence interactions and the resulting flow instabilities. Advanced subgrid-scale modeling techniques will be used to investigate the compressible regime where wave modes exhibit stronger coupling with the flow hydrodynamics.

多孔表面在航空应用中是普遍存在的，其中一些应用包括：抑制燃气涡轮机中的噪声;控制燃烧室中的流动不稳定性;增强机翼在高升力构型下的气动性能，例如在着陆期间;通过冷却剂空气通过孔渗出来控制涡轮机叶片温度;减少高超音速（马赫7）飞行器表面上的气动加热。所有上述应用的核心是：（a）在多孔表面上形成的流动和（B）在表面本身的孔隙空间内捕获的流动之间的相互作用。最先进的建模技术无法模拟这些组合效应下的物理特性。其结果是，在多孔表面的流动控制的技术发展一直受到限制的建模缺乏进展，因此理解，多孔表面的功能和覆盖的流动动力学之间的基本相互作用。拟议研究的目标是在规范流配置中进行高度受控的实验和模拟，这将允许两种方法之间的直接比较，有助于克服上述限制。拟议的研究将通过对工程实践的直接影响对社会产生更广泛的影响。谐振表面的发展将在航空应用中产生重要的技术影响，包括延迟高速边界层的分离和控制商用飞机的后缘噪声。大多数流体机械应用也将受到这一努力的成功影响，因为它提供了增强湍流传热传质和混合的简单方法。此外，该项目将与普渡大学成功的多样性和外展计划合作，包括招聘计划和保留与PI合作的代表性不足的群体。多孔表面与可压缩流相互作用的经典模型通过阻抗边界条件。后者直接在频域中制定，涉及的压力和壁面法向蒸腾速度在表面的傅立叶变换。最近的计算进步允许第一次施加阻抗在时域中的完全可压缩的Navier-Stokes方程求解器通过保留完整的数值和物理可实现性（尊重波传播的因果关系），解锁的关键计算策略需要解开的基本物理之间的耦合可压缩流和多孔表面。这种使能能力提供了一种新颖而优雅的方式来计算模拟多孔表面对上覆流动结构的影响。这使得第一个高保真度的数值模拟的可压缩湍流壁阻抗进行，揭示了基本结构的一个新的自我维持状态的近壁湍流改变声共振。所提出的工作将调查声音湍流的相互作用，通过控制在壁面上的声阻抗的典型设置的湍流通道流湍流在流动条件下，可重复的实验和数值。所提出的努力结合了高度并行的大涡模拟与最先进的实验，其中包括时间分辨层析成像和高分辨率平面粒子图像测速（PIV），直接估计湍流特性和测量不确定性。一个可调谐振表面的实验原型将被开发，并将被用于物理演示这一过程的可行性。一系列新的数值研究将并行进行，支持波湍流相互作用和由此产生的流动不稳定性的分析和建模。先进的亚网格尺度建模技术将被用来调查的可压缩制度，波模式表现出更强的耦合与流动流体动力学。

项目成果

Numerical Investigation of Second-Mode Attenuation over Carbon/Carbon Porous Surfaces

• DOI: 10.2514/1.a34294
• 发表时间: 2019-03
• 期刊: Journal of Spacecraft and Rockets
• 影响因子: 1.6
• 作者: Victor C. B. Sousa;D. Patel;J. Chapelier;V. Wartemann;A. Wagner;C. Scalo

PIV/BOS synthetic image generation in variable density environments for error analysis and experiment design

• DOI: 10.1088/1361-6501/ab1ca8
• 发表时间: 2017-01
• 期刊: Measurement Science and Technology
• 影响因子: 2.4
• 作者: Lalit K. Rajendran;S. Bane;P. Vlachos