TENSOR: Turbulent boundary layer and trailing Edge Noise Study Of flow past a porous surface at high Reynolds number

多孔材料的表面粗糙度和渗透性对湍流边界层的对流有很大的影响，尽管它们各自的影响有很好的文献记载，但它们的联合作用和非线性相互作用却知之甚少。然而，自然界和工程充满了例子，因此，提出了在高雷诺数的湍流和过去这些表面的全面研究。这一点很重要，因为以前的数值研究由于计算成本而仅限于中低雷诺数，而实验同时改变了表面粗糙度和渗透率;因此，无法评估它们的相对贡献。因此，提出了一种新的方法来解耦表面粗糙度从渗透性，这将被用来检查它们的相对重要性的噪声和阻力。该项目将具有航空声学经验的研究人员与应用实验流体力学专家配对，实现互利的知识交流。该研究员将参数调查多孔材料对速度-压力统计的影响，然后使用层析PIV测速法详细调查基本的流动物理学，以建立多孔材料和湍流边界层之间的因果机制。最后，为了测量表面粗糙度和渗透性对后缘散射效率的相对贡献，将在消声风洞中量化散射远场与入射壁压统计的比率。该项目的传播活动将针对预期会产生直接影响的科学界，包括热工程和生物学。加上主持人的能力和业绩记录，将确保成功完成这个雄心勃勃的研究项目，并最大限度地支持研究员的职业发展。

Two aspects of porous materials that substantially influence the turbulent boundary layer convecting over them are surface roughness and permeability, and although their individual effects is well documented, their combined action and non-linear interaction are poorly understood. Nevertheless, nature and engineering are replete with examples; therefore, a comprehensive study of turbulent flows over and past these surfaces is proposed at high Reynolds number. This is important because previous numerical studies were limited to low-moderate Reynolds number due to computational costs, while experiments have altered the surface roughness and permeability at the same time; thus, their relative contribution could not be assessed. Therefore, a novel methodology is proposed to decouple surface roughness from permeability, which will be used to examine their relative importance on noise and drag. The project pairs a researcher with experience in aeroacoustics with an expert in applied experimental fluid mechanics, achieving a mutually beneficial exchange of knowledge. The Fellow will parametrically survey the effects of porous materials on velocity-pressure statistics, followed by a detailed investigation of the underlying flow physics using Tomographic PIV velocimetry to establish cause-and-effect mechanisms between porous materials and turbulent boundary layer. Finally, to measure the relative contribution of surface roughness and permeability on the scattering efficiency of trailing-edge, the ratio of the scattered far-field to the incident wall-pressure statistics will be quantified at the anechoic wind tunnel. The project will target its dissemination activities atscientific communities where the immediate impact is expected, including thermal engineering and biology. Together with the host's capabilities and track record, will ensure successful completion of this ambitious research project and maximally support the fellow's career development.