CBET-EPSRC: Transition and Turbulence in Compressible Boundary Layers Subjected to Concave Surface Curvature

凹面可压缩边界层流动以Gortler涡为特征，广泛存在于涡轮叶片、高速飞机机翼、超音速风洞喷嘴等流体工程应用中。这项工作的总体目标是数值研究凹面上可压缩边界层的空间发展，从层流区域到完全湍流区域，并促进对Gortler涡诱导的转折和超音速凹面曲率下空间发展的壁面湍流的基本理解和预测。这项研究将由英国和美国的调查人员联合进行，他们是完美的互补。边界层物理的详细研究还将与大涡模拟和雷诺平均N-S(RANS)相结合，以评估以Gortler涡为主的过渡流次网格尺度和RAN模式的性能。由于RANS模式缺乏必要的物理基础来包括上游历史对边界层扰动的影响，因此将把DNS数据与基于RANS的预测进行比较，以评估初始湍流区的计算质量。该数据还可用于评估LES对于不同的LES滤波器特性再现过渡区的能力。在研究工作的同时，将开展各种教育活动，向各级学生展示和灌输网络物理发现的兴奋之情，并培养一支在高速流动和先进网络基础设施方面训练有素的劳动力。

Compressible boundary-layer flows over concave surfaces, characterized by Gortler vortices, are ubiquitous in a large number of fluid engineering applications, such as turbine blades, high-speed aircraft wings, and nozzles in supersonic wind tunnels. The overall objectives of this proposed work are to numerically investigate spatially developing compressible boundary layers over concave surfaces, from the laminar regime up to the fully turbulent regime, and to advance both the fundamental understanding and prediction of Gortler-vortex-induced transition and spatially developing wall-bounded turbulence subject to concave surface curvature at supersonic Mach numbers. The research will be conducted jointly by UK and US investigators who perfectly complement each other. The detailed study of boundary-layer physics will also be combined with large-eddy simulations and Reynolds-averaged Navier-Stokes (RANS) to assess the performance of subgrid-scale and RANS models for transitional flows dominated by Gortler vortices. Because RANS models lack the physical basis necessary to include the effects of the upstream history on boundary-layer disturbances, the DNS data will be compared with RANS-based predictions to assess the quality of the computation of the initial turbulent region. The data can also be used to evaluate the ability of LES to reproduce the transition zone for different LES filter characteristics. In conjunction with the research effort, a variety of educational activities will be undertaken to showcase and instil the excitement of cyberphysics discovery in students at all levels, as well as to prepare a highly-trained workforce in high-speed flows and advanced cyberinfrastructure.