Experimental researches for scaling laws of low-order structure function in boundary layer

ZHANG Ke¹, LI Wan-ping²

1.Academy of Civil Engineering and Mechanics,Huazhong University of Science and Technology,Wuhan 430074,China;2.School of Urban Construction,Anhui Radio & TV University,Hefei 230001,China



Abstract:

Scaling laws are addressed by analysing moments of velocity increments which obtained by Particle-image Velocimetry(PIV)system in the boundary layer of a flat plate.In the paper,we measure the moments of increments of upstream velocity(u’),longitudinal velocity(v’)and ponderance of vorticity(dv’/dx)at Reθ=2167 in different wall distance and verify the anomaly of the scaling exponents of high-order structure functions with the increasing order of the moments,discuss the scaling of non-integer moments of order between+2 and-1.The difference of scaling exponents of low-order structure functions between the experimental data and Kolmogorov’s,SL’s(She & Leveque)prediction increases as the moment order decreases toward-1,which shows that the anomaly is manifested in low-oeder moments as well.However,for same order structure functions,the scaling exponents of v’ and dv’/dx are not changeable in different wall distance.

Key words:  scaling law  low-order structure function  turbulent boundary layer  scaling exponent

DOI：10.11916/j.issn.1005-9113.2010.06.013

Clc Number:O357.5

Fund: