船舶吃水对微气泡减阻影响的水池试验研究

Test Research on Drag Reduction of Ship Model at Different Draft by Microbubble in TowingBasin

针对大比尺平底型船模 ,分别在船模底部的首、中部安装多孔硅材料板以生成微气泡 ,在大型拖曳水池中进行了不同拖曳速度、不同喷气量下 ,吃水对减阻率影响的对比性试验。试验结果表明 ,仅在首部喷气以及首、中部等量同时喷气且Fr≤ 0 6 46时 ,浅吃水时的减阻效果好。Fr <0 6 46时 ,浅吃水下纵倾角较深吃水明显减小 ;Fr >0 6 46时 ,浅吃水下纵倾角增幅较深吃水大。

Drag reduction by injecting microbubbles from two perfor at ed plates fixed on the bottom of both bow and middle of a ship model is test r esearched. The test is carried out in a lar ge towing basin at three different drafts of the model, five towing speeds and five gas flow rates with three dif ferent injection forms. Test results show that the efficiency of drag reduction by injecting microbubbles both at t he bow and in the middle of the model at the same time and only at the bow of it with the same gas flow rate a t a shallow draft is better than at a deep draft when Fr≤0. 646, and the trim angle at a shallow draft is obvio usly smaller than at a deep draft when Fr<0.646, whereas the trim angle at a shallow draft is larger than at a de ep draft when Fr>0.646. The test results provide a useful basis for a full-sized ship.