Collaborative Research: Extreme Thermal Transport Events in Supersonic and Hypersonic Shock Wave-Turbulence Interactions

接近或超过声速的高速流动会引起强烈的空气动力学加热，这需要复杂的热保护系统。高温与激波和湍流等极端流动事件相结合，会降低推进装置的寿命，如燃气涡轮发动机、高性能飞机航空发动机、超燃冲压发动机、火箭、起飞和再入飞行器等。该项目将解决激波和湍流相互作用过程中复杂的热传输过程，目标是实现更安全、更可靠的航空推进发动机。将通过平行教育/外展组成部分，例如在研究生教育中纳入研究成果，以及在专题讨论会和会议上发表报告，促进基本的理解，以及培训、教学和学习。妇女、少数民族学生、大学生以及当地高中的教师和学生也将参加。本项目旨在通过考虑以下因素来提高对热湍流输运的理解：(a)激波模式、角度、方向和强度的影响，以及改变热传递和表面热传递的激波不稳定性的来源和模式，(b)激波不稳定性改变并传播到亚音速边界层区域以影响近壁热传递机制和表面热传递的手段，(c)激波诱导分离的强度和相对大小对热传递的影响，(d)激波压缩加热、粘性摩擦加热和动能向内能转换对热传递的影响，以及(e)由此导致的湍流和标量通量、二阶湍流量、相干性和滞后分布的变化。不同类型激波的非定常运动和非定常、空间变化的表面传热和热传递将通过协调的实验计算研究来考虑。将采用一种新开发的超音速风洞系统，以及大涡模拟，以提供详细的流动和热场特性。关键的因果关系将通过理解：(i)相关的热输运特征，（ii）不同流动条件下事件之间的空间依赖和频率依赖的相干性和时间滞后，（iii）非定常流动特征的高分辨率实验可视化，定量流动信息将被确定，以及（iv）来自数值预测的时空流动和热场数据。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。

High-speed flows near or exceeding the speed of sound causes intense aerodynamic heating, which requires sophisticated thermal protection systems. The high temperatures combined with extreme flow events, such as shock waves and turbulence, reduce the life of propulsion devices, such as gas turbine engines, high performance aircraft aero-engines, scramjets, rockets, lift-off and reentry vehicles, among others. The project will address complex thermal transport processes during the interactions of shock wave and turbulence with the goal of enabling safer and more reliable aero-propulsion engines. Fundamental understanding will be promoted, along with training, teaching, and learning by means of parallel education/outreach components, such as incorporation of findings in graduate education, and presentations in symposia and conferences. Women, minority students, and undergraduate students will also participate, as well as both teachers and students from local high schools. This project seeks to improve the understanding of thermal turbulence transport by considering: (a) effects of shock wave mode, angle, orientation, and strength, and the sources and modes of shock wave unsteadiness which alter thermal transport and surface heat transfer, (b) the means whereby shock wave unsteadiness alters and propagates into subsonic boundary layer regions to affect near-wall thermal transport mechanisms and surface heat transfer, (c) effects of the strength and relative size of shock wave induced separation on thermal transport, (d) effects of shock wave compression heating, viscous friction heating, and conversion of kinetic energy to internal energy on thermal transport, and (e) resulting alterations to turbulence and scalar fluxes, second order turbulent quantities, and coherence and time lag distributions. Unsteady motions of different types of shock waves and unsteady, spatially-varying surface heat transfer and thermal transport will be considered through a coordinated experimental-computational study. A newly developed supersonic wind tunnel system will be employed, along with large eddy simulations, to provide detailed flow and thermal field characteristics. Crucial causal relationships will be clarified through understanding of: (i) associated thermal transport characteristics, (ii) spatially-dependent and frequency-dependent coherence and time lag between events at different flow conditions, (iii) highly-resolved experimental visualizations of unsteady flow features from which quantitative flow information will be determined, and (iv) spatio-temporal flow and thermal field-data from numerical predictions.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.