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产生强烈的空气动力加热，这需要复杂的热保护系统。高温加上激波和湍流等极端流动事件，降低了推进装置的寿命，如燃气轮机发动机、高性能飞机航空发动机、超燃冲压发动机、火箭、升空和再入飞行器等。该项目将解决激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。将通过并行教育/外展内容，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的陈述，促进基本理解以及培训、教学和学习。女性、少数民族学生和本科生以及当地高中的老师和学生也将参加。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)冲击波模式、角度、取向和强度的影响，以及改变热传输和表面换热的冲击波不稳定的来源和模式，(B)冲击波不稳定改变和传播到亚音速边界层区域以影响近壁热传输机制和表面换热的方法，(C)激波诱导分离的强度和相对尺寸对热传输的影响，(D)冲击波压缩加热、粘性摩擦加热和动能向内能转换对热传输的影响，以及(E)由此引起的湍流和标量通量、二阶湍流量以及相干和时滞分布的变化。不同类型激波的非定常运动和非定常、空间变化的表面换热和热输运将通过实验和计算相结合的研究来考虑。新开发的超音速风洞系统将与大涡模拟一起使用，以提供详细的流动和热场特性。关键的因果关系将通过了解：(I)相关的热传输特征，(Ii)不同流动条件下事件之间的空间相关和频率相关的一致性和时间滞后，(Iii)非定常流动特征的高分辨率实验可视化，将根据其确定定量流动信息，以及(Iv)时空流动和热场-来自数值预测的数据。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.