Abstract:

Scaling laws in the wall region of a turbulent flow were addressed by analyzing the moments of velocity increments obtained by the particleimage velocimetry (PIV) system in

the boundary layer of a flat plate. The moments of increments of upstream velocity (u′) and longitudinal velocity (v′) were measured at　Reθ=2?167 in different wall distances

and the scaling of noninteger moments of order between +2 and -1 were discussed. 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order moments as

well.

Key words: scaling law, turbulent boundary layer, scaling exponent