梯度扩散理论在能量和物质输送计算中的若干问题

PROBLEMS OF THE GRADIENT-DIFFUSION THEORY IN ITS APPLICATION TO THE DETERMINATION OF MASS AND ENERGY FLUXES

本文用近年来的大量观测结果,揭示了被长期使用的梯度扩散理论的问题和局限性。讨论了它的成立条件:只有当湍流的涡旋尺度远小于梯度变化的空间尺度时,梯度扩散理论才可以正确使用。对于几种典型的近地层条件,计算了它们的湍流的涡旋尺度,从而说明了梯度扩散理论在这些条件下失败的原因。

Problems and limitation of the gradient-diffusion theory have been revealed with experiments recently made, The validity of this theory has also been discussed, the length scale of eddies must be much less than the spatial scale of the variation of gradients In terms of the Eulerian integration method the length scales of eddies were estimated for several examples in the near-surface air layer, under which the gradient-diffusion theory failed to be effection