On the Wind and Turbulence in the Lower Atmosphere above Complex Terrain

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.

基于地形高程数据的复杂地形风场建模方法

提出了一种以地形高程数据为基础,进行三维复杂地形建模及其风场分布求解的数值仿真方法.该方法利用曲面样条插值技术建立复杂地形的三维数字模型,并将地形曲面离散为若干个涡环网格,结合位势流理论与地面边界条件计算得到复杂地形影响下的三维风场.数值计算结果显示,相比基于球绕流理论的工程模拟方法,该方法可对复杂地形做出更为真实的描述,并给出更为合理的风场分布形式.同时该方法建模过程简单,便于实际操作,适于飞机飞行性能评估或飞行模拟器环境建模的工程应用.

城市空中交通无人机群尾流危险区域评估方法

为了避免在城市空中交通无人机群造成的尾流危险遭遇事件的发生,对无人机群产生的复杂尾涡场危害区域进行评估。首先,以单架无人机为基础,建立了适用于无人机群的尾流环量和诱导速度模型。其次,通过计算滚转力矩系数评估后机飞行安全区域。最后,对后机的飞行速度、机翼展长和机翼面积对危险区域的影响进行探究。结果表明:后机在大于旋翼机飞行路径宽度的4.5倍和大于固定翼无人机飞行路径宽度的2.33倍处区域飞行,更能保障飞行安全;后机飞行速度变为原来的3倍时,危险区域覆盖面积减小为原先的1/3;后机翼展变为原来3倍时,危险区域覆盖面积减小为原来的1/3;机翼面积不影响危险区域大小。该模型能更好地预测后机在复杂尾流场下的安全位置,为无人机提供航行指导。