壁湍流的记忆特性及其对涡结构和雷诺应力松弛效应的影响

Wall-bounded turbulence is a typical kind of shear turbulence. Memory effects of wall-bounded turbulence take much influence on the relaxation time of large and small scale structure in the outer region, these structures with memory effects dominate the process of turbulent transport and diffusion. Memory effects and its influence on the momentum and energy transport mechanism in wall-bounded turbulence will be studied in this project, the characteristic scale would be captured using different methods, and the Reynolds number effects of memory effects would be considered. The relaxation effects of Reynolds stress and the laws of energy transfer between different scale structures will be mainly focused considering the memory effects in wall-bounded turbulence. Based on the above guidelines, the structure function and non-Newtonian constitutive fitting methods are planning to be adopted to identify the characteristic time scales of the large scale structures, and the characteristic time scales in different Reynolds numbers would be introduced to describe the relaxation effect of Reynolds stress and the process of energy transfer. This research proposed in this project would provide a systematic understanding of the memory effects on turbulent momentum and energy transport, and enrich the turbulent modeling theory and enhance the understanding of turbulent theory.

壁湍流是一类典型的剪切湍流，其记忆特性对壁湍流涡结构特别是外区的大小尺度结构的弛豫时间有很大影响，进而对湍流的输运和扩散过程起重要作用。本课题拟采用实验、数值和数据分析方法，对壁湍流的记忆特性及其对动量和能量输运影响机理进行研究。采用多种不同的方法捕捉壁湍流的特征尺度，考虑记忆特性的雷诺数效应，主要关注壁湍流外区大尺度结构的记忆特性对雷诺应力松弛效应以及大小尺度湍流结构间能量传递的规律的影响。基于以上分析，通过结构函数和本构关系方法得到壁湍流结构的特征长度尺度和特征时间尺度，从而对雷诺应力松弛效应和湍流能量传递的规律进行描述，探索记忆特性在壁湍流动量和能量再平衡过程中的作用，最终刻画壁湍流记忆特性对动量和能量输运特性影响，丰富湍流模式理论并加深对湍流机理的认识。

壁湍流是一类典型的剪切湍流，其记忆特性对壁湍流涡结构特别是外区的大小尺度结构的弛豫时间有很大影响，进而对湍流的输运和扩散过程起重要作用。本课题采用实验、数值和数据分析方法，对壁湍流的记忆特性及其对动量和能量输运影响机理进行研究。以本课题为依托，近四年以第一作者/通讯作者共计发表论文11篇，其中SCI 7篇，核心4篇；第一作者专利授权1个。通过这些论文、专利的发表，在用结构函数和本构关系方法得到壁湍流结构的特征长度尺度和特征时间尺度，描述雷诺应力松弛效应和湍流能量传递的规律，刻画壁湍流记忆特性对动量和能量输运特性影响，丰富湍流模式理论并加深对湍流机理的认识。这些研究应对于新能源电池散热、海底光缆铺设等有一定的应用前景。