凹槽构型对平板气层减阻影响试验分析

通过平板凹槽喷气减阻模型试验,研究了航速和气流量等因素对平板气层减阻规律的影响,并利用水下摄像系统对不同凹槽构型内的气层形态进行了观测。试验结果表明:不喷气时凹槽的存在会使平板的阻力增加;喷气可以有效减小平板阻力,存在饱和气流量;饱和气流量随着槽深的增加而减小,饱和气流量下平板的绝对减阻率随航速的增加而降低;设置凹槽构型是保持平板下表面气层稳定性的有效措施,合适的凹槽构型可以明显改善平板底部喷气流场,提高平板喷气减阻效果;在Fr为0.119时,饱和气流量下平板的绝对减阻率可以达到40%以上。

Experimental study of the influence of groove configuration on the plate air layer drag reduction

The influence of speed and air flow on the flat gas reservoir law of drag reduction was investigated by an experiment of plate with air injection, and the air layer formation in different groove configuration was observed by underwater imaging system. The results show that grooves increase the resistance of the plate without air; the resistance of flat plate was reduced with air injection, and there is an optimal air flow. The optimal air flow increases with the raise of the groove depth, and the absolute drag reduction rate decreases with the increase of the speed. The configuration of the groove is an effective measure to maintain the stability of the plat bottom surface air layer. The appropriate groove configuration significantly improves the flow field at the bottom of the flat plate and increase the effect of the flat drag reduction with air injection. The absolute drag reduction rate reaches more than 40% under the Fr is 0.119 and optimal air flow.