标量湍流的能量传输特性

应用直接数值模拟数据,从标量湍流传输的三波关系出发,进行湍流及标量湍流传输谱的多尺度分析,研究不同尺度间的能量传输性质,证实标量能量的传输与湍动能传输具有不同性质,大尺度速度脉动对标量传输有较大贡献,尤其是与标量小尺度脉动的相互作用,使标量模拟需要有比速度场更高的网格分辨率;并发现标量湍流的能量传输具有明显的非局部性;另外,定义了能量传输系数,发现在相同的Re数和Pe数条件下,标量湍流的对流惯性较速度脉动的惯性子区宽.

Energy Transfer in Scalar Turbulence

With DNS database, we study the triad interaction of scalar energy transfer, and make a multi-scale analysis in different scales. It shows that the energy transfer in scalar turbulence is different from that in velocity fluctuations. The major contribution of scalar transfer is given by large scale turbulence. Simulation of scalar turbulence requires a higher resolution. The interation between large scale velocity fluctuations and small scale scalar turbulence is an important part of the energy transfer. Non-energy transfer is as important as the local energy transfer in the scalar turbulence. We define an energy transfer coefficient, and find that the inertia-convective range in scalar turbulence is longer than the inertial subrange in turbulent kinetic transfer with same Re and Pe numbers.