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

接近或超过音速的高速气流会引起强烈的气动加热，这需要复杂的热保护系统。高温与诸如冲击波和湍流的极端流动事件相结合，减少了推进装置的寿命，所述推进装置诸如燃气涡轮机发动机、高性能航空器发动机、超燃冲压发动机、火箭、升空和再入飞行器等。该项目将解决冲击波和湍流相互作用期间复杂的热传输过程，目标是实现更安全，更可靠的航空推进发动机。将通过平行的教育/推广组成部分，如将研究结果纳入研究生教育以及在专题讨论会和会议上介绍，促进基本的理解，同时沿着培训、教学和学习。妇女、少数民族学生和本科生以及当地高中的教师和学生也将参加。该项目旨在通过考虑以下因素来提高对热湍流传输的理解：（a）激波模式、角度、方向和强度的影响，以及改变热输运和表面传热的激波不稳定性的源和模式，（B）激波不稳定性改变和传播到亚音速边界层区域以影响近壁热输运机制和表面传热的方式，（c）冲击波诱导分离的强度和相对尺寸对热输运的影响，（d）冲击波压缩加热、粘性摩擦加热以及动能转化为内能对热输运的影响，以及（e）由此产生的湍流和标量通量、二阶湍流量以及相干性和时间滞后分布的改变。将通过协调的实验-计算研究来考虑不同类型激波的非定常运动和非定常的、空间变化的表面热传递和热输送。将采用新开发的超音速风洞系统，沿着大涡模拟，以提供详细的流场和热场特性。将通过了解以下内容来阐明关键因果关系：（i）相关的热传输特性，（ii）不同流动条件下事件之间的空间相关和频率相关相干性和时间滞后，（iii）非定常流动特征的高分辨率实验可视化，从该实验可视化将确定定量流动信息，和（iv）时空流和热场数据的数值预测。该奖项反映了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。

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.