金属丝壁面加热湍流标度律的实验研究

An Experimental Measurement for the Scaling Law in a Boundary Layer over Heated Wall by Metal Wires

通过在固壁表面的平板湍流边界层沿流向平行放置若干通电加热的金属细丝,在平板表面形成沿展向周期性分布的温度场,利用该温度场引起的空气热对流,在湍流边界层近壁区域产生一组沿湍流边界层展向周期分布的流向涡结构。对壁湍流小尺度结构标度律统计特性的研究表明,金属丝加热后形成的规则流向涡结构将壁湍流各种尺度湍涡结构不规则的脉动有序地组织起来,增强了湍流小尺度结构的层次结构相似性,减小了壁湍流中小尺度结构的间歇性和奇异性,抑制了壁湍流中奇异的湍涡结构。

A group of manipulated longitudinal vortex is introduced on the surface of a flat plate in a turbulent boundary layer by a group of longitudinal heated wires. Periodical variation of temperature in span-wise of flow field is formed on the surface of flat plate. With thermal convection of this periodical temperature field, heated wires in the turbulent boundary layer generates a group of longitudinal vortex. The statistic properties of scaling law of turbulent structures show that the disorder fluctuations of all-scale structures are organized by the manipulated order longitudinal vortex introduced by heated wires in the turbulent boundary layer. Self-similarity of hierarchical structure of turbulence is enhanced and singularity and intermittency of turbulent structures are lessened. The singular structures in turbulent flow are also retrained.