ABSTRACT A description of the turbulence kinetic energy budget is investigated to understand the dynamics and turbulence energy transfer between the atmospheric boundary layer and large wind farms. The turbulence kinetic energy budget terms are a dominant factor in explaining the energy supply process in wind farms. Large eddy simulations are used to generate the thermally stratified wind turbine array boundary layer, where stable and unstable conditions are considered. The wakes represent a sink of mean kinetic energy, and turbulence transport redistributes energy in the wake region. The energy balance between the budget terms is dependent on the physical location in the wind farm. During the unstable scenario, turbulence is driven by the production, transport, and buoyancy terms. Further, the contribution of the turbulence kinetic energy budget terms is reduced with increasing atmospheric stability, especially above the shear layer, where the mechanical production is the dominant term. Pressure diffusion redistributes the turbulent energy from the streamwise direction into the other components of the normal Reynolds stresses. This distinctive feature of the changing thermal stratification is presented through the quadrant analysis. The momentum ejection and sweep frequencies are both comparable and dominant. The scalar flux shows an increase in the contribution of the negative correlation in the quadrants. The quadrant analysis is extended to account for intermittency based on the pointwise Hölder exponents. Positive correlations are dominant in the wake and in higher layers of the domain for both considered cases.

中文翻译：

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热分层风电场中的湍流动能收支和动量、标量和间歇通量的条件采样

摘要研究了湍流动能收支的描述，以了解大气边界层和大型风电场之间的动力学和湍流能量转移。湍流动能收支项是解释风电场能源供应过程的主要因素。大涡模拟用于生成热分层风力涡轮机阵列边界层，其中考虑了稳定和不稳定的条件。尾流代表平均动能的汇，湍流传输在尾流区域重新分配能量。预算条款之间的能量平衡取决于风电场中的物理位置。在不稳定的情况下，湍流由生产、运输和浮力项驱动。更多，湍流动能收支项的贡献随着大气稳定性的增加而减少，特别是在剪切层上方，其中机械产生是主要项。压力扩散将湍流能量从流向重新分配到正常雷诺应力的其他分量中。通过象限分析呈现了这种变化的热分层的独特特征。动量喷射和扫描频率既具有可比性又占主导地位。标量通量显示象限中负相关的贡献增加。象限分析被扩展到考虑基于逐点 Hölder 指数的间歇性。对于两种考虑的情况，正相关在域的尾流和更高层中占主导地位。