【摘要】 采用大涡模拟方法研究了存在逆温层的情况下大气对流边界层的湍流特性。实际大气边界层中出现逆温层是较常见的,逆温层会导致大气边界层湍流结构的变化,从而影响大气的湍流扩散和输运特性。本文比较了不同逆温梯度的工况,着重分析了逆温层对边界层中热量逆梯度输运(countergradientheattransportation,CGHT)的影响。计算结果表明:逆温梯度越大,对流边界层的发展越受到抑制;逆温层高度降低会影响整个对流边界层的温度抬升;逆温梯度越大,垂直速度方差越小;在逆温梯度较大的情况下,其逆梯度输运区域要略微低一些,初步分析认为是由于逆温层对热对流的抑制造成的;对于逆温层高度不同的情况,高度越低的逆温层对逆梯度输运的抑制作用更明显。更多还原

【Abstract】 The turbulent characteristics in convective boundary layer topped temperature inversion were numerically investigated in terms of large eddy simulation. The temperature inversin layers can be observed frequently in actual atmosphere boundary layer. The temperature inversion layers cause transformations of the atmosphere boundary layer turbulent structure and then affect the turbulent diffusion and transportation characteristics. In order to analyze the effects of temperature inversion layer on the counter gradient heat transportation in converctive boundary layer, the cases of different temperature gradient were studied. The results indicate that the topped temperature inversion restrains the development of convective boundary layer. The temperature gradient of inversion and the height of inversion affect the region of counter gradient heat transportation.更多还原