断阶3体滑行艇阻力试验研究

通过3体滑行艇不同滑行面形式的对比模型试验,研究了断阶对3体滑行艇阻力性能及运动姿态的影响,比较了3体和单体滑行艇在有无断阶时的阻力性能特点,并对船体2侧喷溅进行了观察.结果表明：无断阶3体滑行艇在第2个阻力峰出现以前阻力与航态的变化趋势同无断阶单体滑行艇一致.加入断阶后3体滑行艇阻力与航态的变化与单体滑行艇加入断阶后的变化不同,断阶3体滑行艇第2个阻力峰消失,阻力随速度的提高而增大,断阶数目越多阻力增长越快;航态变化趋势与无断阶类似,第2次航态出现较大变化的时间随断阶数目的增多而提前.试验中观察发现：无断阶方案的2侧槽道有使喷溅流整顺和形成气垫的作用,而有断阶方案的槽道内喷溅流混乱.

Experimental investigation on resistances from stepped trimaran-planing boats

The influence of different for steps on resistance performance and sailing state of trimaran-planing boat was studied.The characteristics of hydrodynamic performances of trimaran-planing boat and monomer planning boat with or without steps were compared,and their wave spraying was observed.The results show that the trend of resistance performance and sailing state of trimaran-planing boat without steps is the same as those of monomer planning boat before the second drag hump appears.The effects on hydrodynamic performance of adding bottom steps to trimaran-planing and monomer planning boats are different.The second drag hump of stepped trimaran-planing boat disappears and resistance increases with increasing speed.The greater the number of steps,the faster the drag increases.The trend of change on sailing state is similar to that of non-stepped trimaran-planing boat.The second greater change on sailing state appears earlier with increasing of number of step,and the observations in the tests showed that the channels under the non-stepped trimaran-planing boat benefit in regulating the spraying stream forming air-chamber like cushions,which may be the cause of drag reducing in this case,and the spraying stream in multi-stepped trimaran-planing boats appears turbulent.