高速艇自由变深水动力试验研究

通过模型试验,研究了高速艇从压载半潜状态自由变深到高速滑行状态的水动力现象.结果表明,当容积傅氏数大于1.25时,与舷外相通的水能完全自动排出.高速艇自由变深主要有以下5个原因:惯性作用、压载水逐渐排出导致的艇体上抬作用、艇艉由于负压形成的空穴对压载水的吸附作用、艇体动升力导致的艇体上抬作用、有利的艉倾作用.其中对具有较快加速运动的情形,惯性作用起重要地位,艇体动升力在排出流道水方面所发挥的作用相对较小,但在保持流道水排空方面发挥主导作用.

Experimental study on hydrodynamics of high-speed craft with freely varying draft

The hydrodynamics performance of high-speed craft experiencing from loaded semi-submerged condition to high-speed planing condition via freely varying draft is studied by model tests.The result shows that when the volume-Froude number is greater than 1.25,the water opening to outboard can be automatically discharged.The reasons of draft freely varying of high-speed craft are concluded as follows: the inertia effect,the hull lifting caused by the discharging of loaded water,the suction force of cavity caused by the negative pressure at stern,the hull lifting caused by dynamic lift,and the favorable pitch-up,among which the inertia plays the leading role when the acceleration of craft is relative high,and the effect of the dynamic lift on the water discharging in the channel is relatively less while the dynamic lift plays the leading role in keeping the evacuation of the channel.