中文摘要：

沟槽壁面减阻是船舶和管道输运中具有重要应用前景的减阻技术．应用热线测速技术，对沟槽壁面平板湍流边界层的多尺度相干结构被动控制和减阻机理进行了实验测量研究．从壁湍流多尺度相干结构控制的角度分析了沟槽壁面平板湍流边界层的减阻机理．用热线风速仪和双平行丝梯度热线探针测量了风洞中并排放置的沟槽壁面平板及光滑壁面平板湍流边界层在不同法向位置的瞬时流向速度分量及其流向梯度的时间序列信号．用流向速度分量时间序列信号的多尺度子波系数辨识壁湍流多尺度相干结构，用条件采样和相位平均技术提取了壁湍流多尺度相干结构喷射和扫掠时流向速度分量及流向雷诺应力分量的相位平均波形．对沟槽壁面平板及光滑壁面平板湍流边界层多尺度相干结构的多种统计平均特征进行了比较，分析了沟槽壁面平板及光滑壁面平板湍流边界层中多尺度相干结构的条件相位平均波形、流向湍流强度等统计特征．

英文摘要：

Mechanisms for drag reduction in the turbulent boundary layer over a V-grooved riblet surface were studied, which is very important technology to ships and pipeline transportation. Using the hot-wire technique, the experimental study was made on drag reduction mechanism and passive control of multl-scale coherent structure of ttirbulence boundary layer on riblet plate. From the angle of control of multi-scale coherent structure of the turbulence, the drag reduction mechanism was analyzed. Constant temperature anemometry was used to study possible mechanisms of drag reduction. Wind tunnel time sequences of longitudinal velocity components across the turbulent boundary layer over both the riblet surface and a smooth surface were precisely measured by an IFA300 constant temperature anemometer and parallel-double-hot-wire-sensor probe with resolution higher than the Kolmogorov scale. The bursting and sweeping processes of coherent structure were identified by wavelet coefficients of the longi- tudinal fluctuating velocity component. Phased-average waveforms of the longitudinal fluctuation velocity compo- nent, as well as the Reynolds stress component of the coherent structure＇s bursts in the turbulent boundary layer were extracted by the conditional sampling technique. The statistical characteristics of coherent structure, such as burst intensity, phase-averaged waveforms over the turbulent boundary layer of the riblet surface and the smooth surface were compared to clarify the effect of drag reduction over the V-grooved riblet surface.