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，因为它有可能通过将国际旅行时间减少5倍或更多，增强进入太空的能力和加强国防，将地球仪的人们联系起来。传统的空气动力学控制表面在飞行器上，如襟翼和尾翼，在某些速度和高空是无效的，主要是由于地球上层大气的低压力和密度。这就需要对高超音速系统使用替代的飞行器控制手段，这种手段通常采用控制喷气的形式。更好地理解这些相互作用的物理特性也将有助于提高高速发动机的效率并减少其碳足迹。 然而，当喷入高速气流中时，这些射流会在流场中产生大量扰动，建模起来很复杂。目前缺乏适当的预测工具，使基于喷射的控制和燃料喷射不可靠，但在目前的文献基础上存在的这个基本问题的验证质量的实验数据很少。本项目将利用位于圣安东尼奥的得克萨斯大学的马赫数7风洞设备，通过产生进入高超音速横流的喷气流的验证质量实验数据集来满足这一需要。所获得的数据将有助于揭示这种临界流动现象的复杂物理现象，并影响未来的高速飞行器设计。这项研究计划将分三个阶段完成：1）在宽的高速参数空间内深入表征横流中射流的非定常动力学; 2）将横流中射流的流体物理特性与类似的静止圆柱几何形状进行比较; 3）高速横流中射流起始的瞬态动力学研究。这项工作将通过以下方式影响高超音速空气动力学研究：1）量化不同来流边界层状态和马赫数下喷流与横流相互作用的非定常动力学和表面载荷; 2）表征这些喷流相互作用对平板控制力矩的影响; 3）生成模型开发的验证数据。这项研究还将与教育推广紧密结合。鉴于圣安东尼奥人口的多样性和德克萨斯大学圣安东尼奥作为少数民族服务机构的地位，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），并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验将支持每年至少三个暑期学生。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.