2019/04/18 by Duo Wang, Heng Li, Wang, Duo +7
Engineering · Environmental Science · #Aerodynamics and Fluid Dynamics Research #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Turbulent Flows #Heat Transfer Mechanisms #Wind and Air Flow Studies
paper · pdf · doi:10.48550/arxiv.1904.08606
openalex publication_date 2019/04/18 · openalex created_date 2022/07/29 · openalex updated_date 2026/07/28
In-depth analyses of existing direct numerical simulations (DNS) data from\nvarious sources supported a logical and important classification of generic\nturbulent boundary layers (TBL), namely Type-A, -B and -C TBL, based on\ndistribution patterns of time-averaged wall-shear stress. Among these types,\nType-A TBL and its related law, as represented by the DNS data of turbulence on\na zero-pressure-gradient semi-infinite flat-plate, was investigated in terms of\nanalytical formulations of velocity independent on Reynolds ( ) number. With\nreference to the analysis from von Karman in developing the conventional\nlaw-of-the-wall, the current study first physically distinguished the\ntime-averaged local scale used by von Karman from the ensemble-averaged scale\ndefined in the paper, and then derived the governing equations with the\n-independency under the ensemble-averaged scales. Based on indicator function\n(IDF) and TBL thickness, the sublayer partitions were rigorously defined. The\nanalytical formulations for entire TBL, namely the complete law-of-the-wall,\nwere established, including the formula in inner, buffer, semi-logarithmic\n(semi-log) and wake layer. The researches were featured by introducing the\ngeneral damping and enhancing functions (GDF and GEF) and applying these\nfunctions to both linear and logarithmic coordinates. These law formulations\nwere proved uniform and consistent in time-averaged local and ensemble-averaged\nscales, which were validated by the existing DNS and experiment data. Based on\nthe similarity of relevant properly-scaled governing equations, the law\nformulations were logically reasoned being applicable to the temperature in\nType-A thermal TBL. The findings advance the current understandings of the\nconventional TBL theory and its well-known foundations of law-of-the-wall.\n