Fig. 1. Schematic diagram of experimental plates: (a) Smooth plate; (b) riblets; (c) s-riblets实验模型示意图　(a) 光滑平板; (b) 传统直线型沟槽板; (c) 正弦波型沟槽板

Fig. 2. Cross section of s-riblets: (a) Left view; (b) top view正弦波沟槽截面图　(a) 左视图; (b) 俯视图

Fig. 3. Schematic diagram of experimental setup: (a) case 1; (b) case 2.实验装置示意图　(a) case 1; (b) case 2

Fig. 4. Mean velocity profiles in TBL flows over test plates不同壁面流场的流向平均速度剖面

Fig. 5. Distribution of turbulent intensities over test plates不同壁面流场湍流度的分布曲线

Fig. 6. Distribution of Reynolds shear stress over test plates不同壁面流场雷诺切应力的分布曲线

Fig. 7. Correlation coefficients of the streamwise fluctuation in plane over test plates 不同壁面流场流向脉动速度在 平面内的相关系数

Fig. 8. The local motion in the space spanned by the eigenvectors^[50]特征向量空间中的局部流动^[50]

Fig. 9. Conditionally-averaged structure in the plane: (top) = 71.1; (bottom) = 128 平面条件平均相干结构 (上) = 71.1; (下) = 128

Fig. 10. The model of hairpin vortex proposed by Adrian et al.^[51]Adrian等^[51]提出的发卡涡模型

Fig. 11. Instantaneous streamwise fluctuating velocity in plane at = 9.7 平面内不同壁面上流场 = 9.7流向脉动速度云图

Fig. 12. Autocorrelation function of in the -direction over test plates 不同壁面上流场 沿展向的自相关函数