The state-of-art Computational Fluid Dynamics （CFD） codes FLUENT is applied in a fine-scale simulation of the wind field over a complex terrain. Several numerical tests are performed to validate the capability of FL...The state-of-art Computational Fluid Dynamics （CFD） codes FLUENT is applied in a fine-scale simulation of the wind field over a complex terrain. Several numerical tests are performed to validate the capability of FLUENT on describing the wind field details over a complex terrain. The results of the numerical tests show that FLUENT can simulate the wind field over extremely complex terrain, which cannot be simulated by mesoscale models. The reason why FLUENT can cope with extremely complex terrain, which can not be coped with by mesoscale models, relies on some particular techniques adopted by FLUENT, such as computer-aided design （CAD） technique, unstructured grid technique and finite volume method. Compared with mesoscale models, FLUENT can describe terrain in much more accurate details and can provide wind simulation results with higher resolution and more accuracy.展开更多
Numerical modeling and studies of the wind fields at the junction of three continents: over the complex terrains of the South-east Europe, Asia Minor, Middle East, Caucasus and over the Black, Caspian and Medi-terrane...Numerical modeling and studies of the wind fields at the junction of three continents: over the complex terrains of the South-east Europe, Asia Minor, Middle East, Caucasus and over the Black, Caspian and Medi-terranean seas have been carried out for the first time. Traveling synoptic scale vortex wave generation and subsequent evolution of orographic vortices are discovered. Wind fields, spatial distribution of the coefficients of subgrid scale horizontal and vertical turbulence and the Richardson number are calculated. It is shown that the local relief, atmospheric hydrothermodynamics and air-proof tropopause facilitate the generation of β-mesoscale vortex and turbulence amplification in the vicinity of the atmospheric boundary layer and tropopause. Also turbulence parameters distribution in the troposphere has the same nature as in the stratosphere and mesosphere: turbulence coefficients, stratification of the vertical profiles of the Richardson number, thickness of the turbulent and laminar layers.展开更多
风场是影响林火蔓延行为最关键的因素之一。许多林火发生在地形复杂多变的山区,会产生复杂的局部风场。为探究动态风场对林火蔓延预测的影响,以“3·30”西昌泸山森林火灾为研究对象,利用WRF(weather research and forecasting)模...风场是影响林火蔓延行为最关键的因素之一。许多林火发生在地形复杂多变的山区,会产生复杂的局部风场。为探究动态风场对林火蔓延预测的影响,以“3·30”西昌泸山森林火灾为研究对象,利用WRF(weather research and forecasting)模式模拟动态风场,并与林火蔓延模型耦合。分别将模拟风场和均一风场分别输入林火蔓延模型,基于林火蔓延过程中实际火场范围数据,分析动态风场对林火蔓延模型预测结果的影响。结果表明,耦合WRF模式和林火蔓延模型考虑了分辨率更高、且更为准确的局部风场,能够实现对森林火灾蔓延的动态模拟。预测得到的火场范围和均一风场相比,与实际范围具有更高的相似度。展开更多
为了实现复杂地形下高分辨率风场的数值模拟及特征分析,采用中尺度气象模式WRF(Weather Research and Forecasting M odel)结合牛顿松弛逼近Nudging资料同化技术,实现哈密地区水平分辨率1 km的近地层风场数值模拟计算。基于模拟区域测...为了实现复杂地形下高分辨率风场的数值模拟及特征分析,采用中尺度气象模式WRF(Weather Research and Forecasting M odel)结合牛顿松弛逼近Nudging资料同化技术,实现哈密地区水平分辨率1 km的近地层风场数值模拟计算。基于模拟区域测风塔实测数据的对比检验发现,同化观测资料后风速风向的模拟结果均与实测更加接近,70 m高度风速模拟结果的绝对误差降低0. 25 m·s^(-1),同化后的模拟结果可以较好的修正风速较小时模拟值偏高和风速较大时模拟值偏小的问题,同时风廓线的模拟结果也与实测更加吻合。通过分析哈密复杂地形下水平分辨率1 km逐10 min风场输出结果发现:(1)哈密地区地形比较复杂,风速平面分布差异很大,4月份风速较大区域主要分布在山北地区和西部山南垭口附近,而7月份风速较大区域则位于西部的山坳南部和北部地区;(2)复杂地形下风速较小时风速为负切变,且平均风速越小负切变值越大,地形越复杂负切变值越大;风速较大即使是复杂地形下同样为正切变,但是正切变值比平坦地区的值要小,平坦地形下风速越大正切变值越大;(3)哈密地区复杂地形下,风速12～25 m·s^(-1)的风速占比在时间和空间上分布差异较大,风速较大的4月份,大部分地区占比达到20%以上,尤其是山北和西部垭口附近,占比甚至达到了50%以上,风速为12～25 m·s^(-1)的情况下80 m高度平均风速比60 m高0. 60～0. 80 m·s^(-1),比月平均风速的垂直变化值要大;(4)风速较大时,风向10 min变化不明显,风速较小时,风向变化值较大,且地形较平坦地区风向变化值较大,地形复杂地区变化值较小;(5)风向的垂直变化与风速大小关系比较明显,风速越小,其垂直变化越大,风向垂直变化的区域分布与地形复杂程度相关,地形越复杂风向的垂直变化值越大。展开更多
基金supported by the National Natural Science Foundation of China(40805004, 40705039 and 90715031)the "Mini-projecton detailed survey and evaluation of wind energy resources"supported by National Climate Center of Chinese Meteoro-logical Administration (CWERA2010002)
文摘The state-of-art Computational Fluid Dynamics （CFD） codes FLUENT is applied in a fine-scale simulation of the wind field over a complex terrain. Several numerical tests are performed to validate the capability of FLUENT on describing the wind field details over a complex terrain. The results of the numerical tests show that FLUENT can simulate the wind field over extremely complex terrain, which cannot be simulated by mesoscale models. The reason why FLUENT can cope with extremely complex terrain, which can not be coped with by mesoscale models, relies on some particular techniques adopted by FLUENT, such as computer-aided design （CAD） technique, unstructured grid technique and finite volume method. Compared with mesoscale models, FLUENT can describe terrain in much more accurate details and can provide wind simulation results with higher resolution and more accuracy.
文摘Numerical modeling and studies of the wind fields at the junction of three continents: over the complex terrains of the South-east Europe, Asia Minor, Middle East, Caucasus and over the Black, Caspian and Medi-terranean seas have been carried out for the first time. Traveling synoptic scale vortex wave generation and subsequent evolution of orographic vortices are discovered. Wind fields, spatial distribution of the coefficients of subgrid scale horizontal and vertical turbulence and the Richardson number are calculated. It is shown that the local relief, atmospheric hydrothermodynamics and air-proof tropopause facilitate the generation of β-mesoscale vortex and turbulence amplification in the vicinity of the atmospheric boundary layer and tropopause. Also turbulence parameters distribution in the troposphere has the same nature as in the stratosphere and mesosphere: turbulence coefficients, stratification of the vertical profiles of the Richardson number, thickness of the turbulent and laminar layers.
文摘风场是影响林火蔓延行为最关键的因素之一。许多林火发生在地形复杂多变的山区,会产生复杂的局部风场。为探究动态风场对林火蔓延预测的影响,以“3·30”西昌泸山森林火灾为研究对象,利用WRF(weather research and forecasting)模式模拟动态风场,并与林火蔓延模型耦合。分别将模拟风场和均一风场分别输入林火蔓延模型,基于林火蔓延过程中实际火场范围数据,分析动态风场对林火蔓延模型预测结果的影响。结果表明,耦合WRF模式和林火蔓延模型考虑了分辨率更高、且更为准确的局部风场,能够实现对森林火灾蔓延的动态模拟。预测得到的火场范围和均一风场相比,与实际范围具有更高的相似度。
