楔形舵片失速特性的数值模拟和水洞试验

Numerical simulation and water tunnel experiment on the stalling characteristics of wedge rudders

为获得楔形超空化舵片在大舵角情况下的失速特性并探究其失速机理,针对采用24°楔形舵片作为艉控制面的超空泡航行体在低速通气条件下的绕流问题,分别构建三维数值模型和水洞试验系统,同时采用数值模拟和水洞试验两种手段研究楔形舵片的升/阻力特性和低压面空化情况随舵角的变化关系.研究结果表明：提出的数值方法和试验方案是合理的;楔形舵片的阻力系数在0°~5°舵角变化的影响较小,升力系数在0°~8°和9°~12°舵角范围内均具有良好的线性度,但后者斜率远小于前者;楔形舵片在舵角超过8°时升力系数突然减小并发生失速现象,舵片低压面发生空化并被空泡覆盖;低压面因空化致使压力不能进一步降低是导致舵片发生失速的根本原因,对于24°楔形舵片的许用舵角范围不应超过8°.

To obtain the stalling characteristics of wedge rudders under cavitation conditions and to explore the mechanism leading to the stalling,the ventilating cavitation flow field around supercavitating vehicle which uses a24° wedge rudder as the aft control plane was investigated by establishing the three-dimensional numerical simulation model and the water tunnel experimental system. The change law of the wedge rudder’s lift,drag,and cavitation characteristics along with rudder angle were studied by the numerical simulation and water tunnel experiment,respectively. According to the research results,the proposed numerical and experimental methods are reasonable; the drag coefficient of the wedge rudder varies slightly with the rudder angle in the range of 0°-5°; the lift coefficient has good linearity in the rudder angle range of 0°-8° and 9°-12°,but the slope of the former range is considerably bigger than that of the latter range. Moreover,when the rudder angle exceeds 8°,the lift coefficient of the wedge rudder will reduce sharply,stalling will happen,and the low-pressure surface of the wedge rudder will be covered by cavity. Therefore,the cavitation occurring on the low-pressure surface of the wedge rudder may be the main reason leading to the stalling. Furthermore,it is suggested that the allowable rudder angle of the 24°wedge rudder should not exceed 8°.