Abstract—

Despite many advances in numerical simulation of stable boundary layers (SBL), most of the models developed are complex and computationally expensive. A computational fluid dynamics (CFD) strategy is proposed that combines very large eddy simulation (VLES) with a reductionist inflow turbulence generator and wall modeling aimed at affordable and practical simulation of SBL. Unlike the standard LES requiring the filter width to be of the scale of grid size, the filter width in VLES can be set at a value between the grid size and the large characteristic length scales of the flow. This strategy, along with the application of wall treatments, results in the significant reduction of computational costs. Moreover, the reductionist approach of the inflow turbulence generator minimizes the number of required input parameters to the model, which makes the model suitable for practical applications. A series of sensitivity studies are conducted to refine the numerical parameters including the grid resolution, filter width, and the inflow turbulence generator variables controlling the length and time scales of the eddies generated at the inlet. The performance of the model is successfully evaluated against wind-tunnel measurements for mean velocity, mean temperature, and turbulence profiles for four different thermal stability levels ranging from weak to strong stability. The spectral analysis of the model for velocity components, temperature, momentum, and heat fluxes showed that the model is capable of successfully resolving the energy cascade for almost two orders of magnitude of wave numbers and partially matching the well-known log-log slopes for the inertial subrange.

中文翻译：

---

使用还原论入口湍流发生器和稳定大气边界层的壁面建模的超大涡流模拟模型

摘要——

尽管在稳定边界层 (SBL) 的数值模拟方面取得了许多进展，但开发的大多数模型都很复杂且计算量很大。提出了一种计算流体动力学 (CFD) 策略，该策略将超大涡流模拟 (VLES) 与还原性流入湍流发生器和壁面建模相结合，旨在对 SBL 进行经济实用的模拟。与标准 LES 要求过滤器宽度与网格尺寸的尺度不同，VLES 中的过滤器宽度可以设置为网格尺寸和流的大特征长度尺度之间的值。这种策略，连同墙壁处理的应用，导致计算成本的显着降低。此外，流入湍流发生器的简化方法最大限度地减少了模型所需输入参数的数量，这使得该模型适用于实际应用。进行了一系列敏感性研究以改进数值参数，包括网格分辨率、过滤器宽度和控制入口处产生的涡流的长度和时间尺度的流入湍流发生器变量。针对平均速度、平均温度和湍流剖面的风洞测量，成功评估了模型的性能，这些测量结果是从弱稳定性到强稳定性的四种不同热稳定性水平。该模型的速度分量、温度、动量和热通量的谱分析表明，该模型能够成功解析几乎两个数量级的波数的能量级联，并部分匹配众所周知的对数斜率惯性子域。