槽道湍流近壁区多尺度输运特性研究

利用槽道湍流直接数值模拟的数据库和离散正交子波，对近壁湍流的多尺度输运特性进行了研究. 通过在流向和展向分别进行子波多尺度分解，得到了近壁区湍动能在流向和展向多尺度传输的不同性质，发现流向传输以能量的反传为主，而在展向能量存在明显的正传，并且当过滤尺度较大时以正传为主. 近壁湍流能量传输的各向异性为进一步构造各向异性大涡模拟亚格子模式提供了必要的参考.

MULTI-SCALE ENERGY TRANSFER IN NEAR-WALL REGION OF TURBULENT CHANNEL FLOW

The multi-scale energy transfer in near-wall turbulence is studied by orthonormal wavelets and the database of channel turbulence obtained by direct numerical simulation. By a multi-scale decomposition of the flow field in streamwise and spanwise directions, the difference of energy transfer between these two directions is investigated. It is found that the energy transfer in the streamwise direction is dominated by back scatter, while in the spanwise direction, there is an obvious forward transfer, which is not confined in the viscous sublayer only like that in the streamwise direction. With a lager filter width, the forward energy transfer in the spanwise direction becomes dominant.