A new large-eddy simulation model for simulating air flow and warm clouds above highly complex terrain. Part I: The dry model
A new large-eddy simulation model for simulating air flow and warm clouds above highly complex terrain. Part I: The dry model
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DOI：
10.1007/s10546-007-9183-8
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发表时间：
2007-05
影响因子：
4.3
通讯作者：
D. Reinert;V. Wirth;J. Eichhorn;W. Panhans
中科院分区：
文献类型：
--
作者：
D. Reinert;V. Wirth;J. Eichhorn;W. Panhans
本文介绍了一个新的大涡模拟（LES）模式，它是专为模拟高度复杂的地形上空的气流和云的干燥版本。模型为三维非静力模型，控制方程采用滞弹性近似进行合理滤波。在交错直角坐标网格上，采用分步方法求解方程组。用粘性地形的方法可以解释陡峭复杂的地形。动力学模型的核心进行了验证，通过比较结果的扩展密度电流对基准解决方案。通过模拟准二维山脊上的湍流流动，进一步评估了模型的精度。计算结果与风洞试验数据进行了比较。粘性地形法并不局限于中等坡度的地形。与使用曲线网格的模型相比，它允许该模型适用于更广泛的流动范围。这是说明通过模拟的大气边界层流动的表面安装立方体。结果表明，干模型能够准确地模拟三维障碍物附近的复杂流动。结果表明，粘性地形法成功地应用于微气象大涡模拟中。正如第二部分所示，这使得在高度复杂的地形中对云进行详细的研究成为可能。
This paper presents the dry version of a new large-eddy simulation (LES) model, which is designed to simulate air flow and clouds above highly complex terrain. The model is three-dimensional and nonhydrostatic, and the governing equations are sound filtered by use of the anelastic approximation. A fractional step method is applied to solve the equations on a staggered Cartesian grid. Arbitrarily steep and complex orography can be accounted for through the method of viscous topography. The dynamical model core is validated by comparing the results for a spreading density current against a benchmark solution. The model accuracy is further assessed through the simulation of turbulent flow across a quasi two-dimensional ridge. The results are compared with wind-tunnel data. The method of viscous topography is not restricted to moderately sloped terrain. Compared to models using curvilinear grids, it allows this model to be applied to a much wider range of flows. This is illustrated through the simulation of an atmospheric boundary-layer flow over a surface mounted cube. The results show that the dry model version is able to accurately represent the complex flow in the vicinity of three-dimensional obstacles. It is concluded that the method of viscous topography was successfully implemented into a micrometeorological LES model. As will be shown in Part II, this allows the detailed study of clouds in highly complex terrain.