利用循环管路系统,对方形管道内壁面微结构对湍流减阻效果的影响进行了试验研究,研究了循环管路系统不同壁面微结构下流动的范宁系数和减阻率.试验采用的肋条结构尺寸为:肋条宽度均为1.0mm,肋高分别是h=0.3mm、0.5mm、0.7mm.试验介质为普通自来水,水温控制在25℃±0.5℃,水平管道内流体流速范围为0.03～1.80m/s.试验研究结果表明:在量纲为1的肋深h+处于4～15范围内,肋条壁面的范宁系数小于光滑壁面的范宁系数,肋条壁面具有减阻效果;肋高h=0.5mm肋条的减阻效果最好,最大减阻率为11.91％;粒子成像测速仪研究了不同壁面微结构下流体流动的平均速度、雷诺切应力和近壁区的涡量.实验结果表明:肋条的存在使得湍流边界层增厚,雷诺切应力减小,近壁区的涡量降低,从而达到减阻的效果.%In the present work, the flow characteristics and drag reduction of a turbulent flow field over a riblets surface plate were investigated experimentally and compared with a smooth surface. Experimental tests were carried out in a closed rectangular duct with 1mm in width and 0.3mm, 0.5mm,0.7mm in height riblets using particle image velocimetry. Tap water was used in this experiment and test temperature was controlled at 25℃±0.5℃,and the velocity was maintained between 0.03—1.8m/s. The study showed that a notable decrease in fanning friction factor for riblets surfaces can be seen at an h+ range of 4–15 compared with flat plate. A maximum rag-reduction of nearly 11.91 percent was acquired over the riblets surface of 1 mm wide and 0.5 mm height. Riblet can thicken the boundary layer and weaken turbulent fluctuation intensity. Furthermore,both Reynolds shear stress and vorticity and root-mean-square velocity were decreased.
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