A Conservation-Based Transitional Boundary Layer Model
A Conservation-Based Transitional Boundary Layer Model
复制标题
基于守恒的过渡边界层模型
DOI：
10.1115/1.4054838
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Brewster, M. Q.
中科院分区：
文献类型：
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作者：
Brewster, M. Q.
提出了一个简单的、基于流动物理的平板、过渡边界层表面摩擦和传热模型。该模型是基于可忽略的时间，展向和流向的平均壁面法向速度在边界层顶部的假设。这导致过渡区边界层厚度增加三倍。这个简单的速度假设和它的边界层增长的影响似乎是合理的更复杂的（直接数值模拟（DNS））建模模拟一致。只需要假设两个建模参数，即转捩开始和结束时的雷诺数，对于这两个参数，有基于光滑板的自由湍流强度的指导。空气的几个实验数据集进行了建模。提出了新的标准，以帮助定义的开始和完成的过渡：零净垂直（壁法向）速度或质量通量（整合在时间和空间，展向和流向）在边界层的顶部，边界层厚度的三倍。还提出了一个小的改进，以前公布的未加热的平板层流边界层均匀壁热流的起始长度因子。
A simple, flow-physics-based model of flat-plate, transitional boundary layer skin friction and heat transfer is presented. The model is based on the assumption of negligible time-, spanwise-, and streamwise-average wall-normal velocity at the top of the boundary layer. This results in a threefold increase in boundary layer thickness over the transition region. This simple velocity assumption and its boundary-layer growth implications seem to be reasonably consistent with more sophisticated (direct numerical simulation (DNS)) modeling simulations. Only two modeling parameters need to be assumed, the Reynolds numbers at the onset and at the completion of transition, for which there is guidance based on freestream turbulence intensity for smooth plates. Several experimental datasets for air are modeled. New criteria are proposed to help define the onset and completion of transition: zero net vertical (wall-normal) velocity or mass flux (integrated in time and space, spanwise and streamwise) at the top of the boundary layer, and tripling of boundary layer thickness. Also presented is a minor improvement to a previously published unheated starting length factor for flat-plate laminar boundary layers with uniform wall heat flux.