CAREER: Experimental Investigation into the Impact of Incoming Boundary Layer State on the Unsteady Dynamics of a Transverse Jet in a Hypersonic Crossflow

高超音速飞行具有明显的吸引力，因为它有可能将全球各地的人们联系起来，将国际旅行时间减少5倍或更多，增强进入太空的机会，并加强国防。由于地球上层大气的低压和低密度，飞机上的传统气动控制面（如襟翼和尾翼）在某些速度和高海拔地区是无效的。这就需要对高超声速系统使用替代的飞行器控制手段，通常采用控制喷气机的形式。提高对这些相互作用的物理理解也将有助于提高高速发动机的效率并减少其碳足迹。当射入高速流时；然而，这些射流会在流场中产生巨大的扰动，这是很难建模的。目前缺乏适当的预测工具，使得基于喷气的控制和燃油喷射不可靠，而在现有的文献基础上，几乎没有验证质量的实验数据。该项目将利用位于圣安东尼奥的德克萨斯大学的7马赫风洞设施，通过生成验证质量的喷气机进入高超音速横流的实验数据集来解决这一需求。获得的数据将有助于揭示这一临界流动现象的复杂物理现象，并影响未来高速车辆的设计。本研究计划将分三个阶段完成：1)深入表征宽高速参数空间内横流射流的非定常动力学；2)横流射流流体物理与类似立柱几何的比较；高速横流中射流起爆的瞬态动力学研究。这项工作将通过以下方面对高超声速气动研究产生影响：1)量化不同来流边界层状态和马赫数下射流-横流相互作用的非定常动力学和表面载荷；2)描述了这些射流相互作用对平板控制力矩的影响；3)为模型开发生成验证数据。这项研究也将与教育推广紧密结合。鉴于圣安东尼奥市人口多样化，以及德克萨斯大学圣安东尼奥分校作为少数族裔服务机构的地位，该项目将作为一个平台，吸引不同群体的学生。雄心勃勃的教育活动包括将研究纳入新课程（每学期100名学生）和通过创新课程设计项目。与当地社区大学合作伙伴的实习经历每年将支持至少三名暑期学生。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Hypersonic flight has obvious appeal given the potential to connect people across the globe by reducing international travel times by a factor of 5 or more, enhancing access to space, and strengthening national defense. Traditional aerodynamic control surfaces seen on aircraft like flaps and fins are ineffective at certain speeds and high altitudes owing primarily to the low pressures and densities in the Earth’s upper atmosphere. This necessitates the use of alternative means of vehicle control for hypersonic systems, which generally takes the form of control jets. An improved understanding of the physics of these interactions will also help improve high-speed engine efficiency and reduce their carbon footprint. When fired into a high-speed flow; however, these jets can create massive disturbances in the flowfield that are complex to model. The current lack of proper predictive tools has rendered jet-based control and fuel-injection unreliable, yet little validation-quality experimental data for this fundamental problem exists in the current literature base. This project will address this need by producing validation-quality experimental datasets of jets issuing into a hypersonic crossflow using the Mach 7 wind tunnel facility at The University of Texas at San Antonio. The acquired data will help unravel the complex physics of this critical flow phenomenon and impact future high-speed vehicle design.This research program will be accomplished in three phases: 1) in-depth characterization of the unsteady dynamics of a jet-in-crossflow over a wide high-speed parameter space; 2) comparison of jet-in-crossflow fluid physics to an analogous standing cylinder geometry; 3) investigation of the transient dynamics of the initiation of a jet in a high-speed crossflow. This work will impact hypersonic aerodynamic research by: 1) quantifying unsteady dynamics and surface loads of jet-in-cross-flow interactions for varied incoming boundary layer states and Mach numbers; 2) characterizing the impact of these jet interactions on control moments for a flat plate; 3) generating validation data for model development. This research will also be tightly integrated with educational outreach. Given the diverse population in San Antonio and The University of Texas at San Antonio’s status as a minority-serving institution, this project will serve as a platform to engage a diverse group of students. The ambitious educational activities include the incorporation of research into new courses (100 students per semester) and design projects through innovative curricula. Internship experiences with local community college partners will support at least three summer students each year.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.