舰载直升机起降区空气流场模拟方法研究

Research of simulation methods on landing flow field for shipborne helicopters

基于计算流体力学(CFD)技术建立了2种舰载直升机起降区空气流场的计算方法,以用于分析舰船/直升机之间的耦合干扰问题。在这2种方法中,控制方程选取N-S方程,求解方式采用隐式耦合方式,湍流模型为k-ε模型,分别使用"作用盘方法"和"运动嵌套网格方法"模拟旋翼。应用建立的方法,以SFS2简化船型、Robin旋翼和"Caradonna-Tung"旋翼分别作为算例,并与试验值进行对比,验证了方法的有效性。在此基础上,深入地进行起降区舰船/旋翼耦合流场的计算研究。研究结果表明:舰船上层建筑物的存在会引起起降区下洗速度增大,使得旋翼拉力减小;"作用盘方法"能有效地用于舰船/直升机耦合流场的分析,而"运动嵌套网格方法"可以捕捉到起降区空气流场的细节,但其需要耗费巨大的计算量。

Two computational methods based on CFD technology are established for shipborne helicopter＇s landing flow field, which can effectively be used to analyze the coupled interaction between a ship and a helicopter. In both methods,N-S equations are employed as the governing equations. The implicit method is selected as solver method, and the k-ε model is used as the turbulence model. An adaptive trimmed mesh is used to generate the grid of computational regions. The actuator disk method and overset mesh method are employed to model the effect of rotor. In order to verify established methods, an SFS2 ship, a Robin rotor and a Caradonna-Tungrotor are taken as examples respectively, and the calculated values are compared with available experimental data. Then, the coupled interaction between rotor downwash and the ship flow field is deeply analyzed. It is showed that the presence of the upper structure above the deck increases the downwash velocity of landing flow field, which reduces the rotor lift. The actuator disk method can effectively be used to analyze the coupled flow field between ship and helicopter, and the overset mesh method can capture more details of the landing flow field, but will cost huge computational resources.