Collaborative Research: Reaping the Whirlwind: Re-energizing Boundary Layers by Targeted Manipulation of Coherent Structures

合作研究：收获旋风：通过有针对性地操纵相干结构来重新激活边界层

• 批准号: 2129493
• 负责人: Michael Amitay
• 金额: $ 23.49万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2129493&HistoricalAwards=false
• 关键词: Collaborative; Research; Reaping; Whirlwind; Re

In a turbulent flow, for example near the surface of an airplane wing or in the atmosphere as it flows over the Earth’s surface, there is a range of eddies of different sizes. The largest of these coherent eddies, called Large Scale Motions (LSMs), carry a significant portion of the turbulent kinetic energy and are largely responsible for mixing high-speed flow far away from the surface with the low-speed flow right near the surface. This mixing may be enhanced by selectively displacing the LSMs toward the surface, and this is very desirable in some applications. For example, bringing high-speed flow to the surface can keep a wing from stalling and losing its lift. The goal of this project is to prove via simulations and in matched experiments an approach to detect and manipulate LSMs to re-energize the near-surface flow. The success of the present approach is also expected to motivate the emergence of technologies such as controlling acoustic noise or heat transfer for underwater, ground-vehicles, or air-vehicles or combustion in turbomachinery. This project thus has the potential of initiating a new direction in turbulent flow control. The goal of this research is to develop an experimentally-validated system for active detection and manipulation of LSMs for turbulent boundary layer re-energization. Advances in the fundamental understanding of LSMs, actuator innovations, and advanced control theory make this goal achievable. The first step towards the goal is to demonstrate energizing a boundary layer by manipulating controlled, well-characterized, synthetically generated structures in well-coordinated boundary layer experiments and direct numerical simulations (DNS). The preliminary DNS successfully demonstrated optimization of control jet actuation using two different control methods, which deflected a prototypical LSM towards the surface. Preliminary work has created a suitable actuator based on a synthetic jet and demonstrated it in the lab. The specific tasks proposed in this collaborative 3-year project are: (1) develop and implement control algorithms to selectively move synthetically generated LSMs in matched experiments and DNS, (2) quantify the re-energization achieved by moving different kinds of LSMs to guide target prioritization, and (3) test and optimize the re-energization of a turbulent boundary layer with an eye toward separation control and wind power applications. The results of this project will be made publicly available through online platforms and enhanced classroom activity. The project will also help recruit graduate students from underrepresented groups and for several undergraduate research projects.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在湍流中，例如在飞机翼的表面附近或在大气中流过地球表面时，有一系列不同尺寸的涡流。这些连贯的涡流中最大的涡流（称为大型运动（LSM））具有很大一部分湍流动能，并且在很大程度上负责将远离表面的高速流与低速流动靠近地面混合。可以通过选择性地将LSM朝向表面来增强这种混合，并且在某些应用中非常理想。例如，将高速流到表面可以防止机翼拖延和失去升力。该项目的目的是通过模拟和匹配的实验证明一种检测和操纵LSM的方法以重新启动近表面流。当前方法的成功还有望激发技术的出现，例如控制水下，地下车辆或气动车辆或涡轮机械组合的声音噪声或传热。因此，该项目具有启动湍流控制方向的新方向。这项研究的目的是开发一个实验验证的系统，用于积极检测和操纵LSM，以进行湍流边界层的重新启动。在对LSM，执行器创新和高级控制理论的基本理解方面提高了这一目标。朝着目标迈进的第一步是通过操纵在良好的边界层实验和直接数值模拟（DNS）中操纵受控，良好的，合成的结构来证明边界层。初步DNS成功地证明了使用两种不同的控制方法对控制射流驱动的优化，该方法击败了朝向表面的原型LSM。初步工作创建了一个基于合成喷气的合适的执行器，并在实验室中证明了这一点。 The specific tasks proposed in this collaborative 3-year project are: (1) developing and implement control algorithms to selectively move synthetically generated LSMs in matched experiments and DNS, (2) quantify the re-energization achieved by moving different kinds of LSMs to guide target prioritization, and (3) test and optimize the re-energization of a turbulent boundary layer with an eye towards separation control and wind power applications.该项目的结果将通过在线平台和增强的课堂活动公开提供。该项目还将帮助来自代表性不足的小组的招募研究生，并为几个本科研究项目。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响评估标准，被视为通过评估来获得支持。