主动射流控制对直升机着舰飞行的影响分析

Influence of active flow control on shipborne helicopter landing

摘要:

为改善直升机舰面起降过程中起降安全性,基于单向耦合策略建立了一套适用于直升机/舰船动态界面（dynamic interface）研究的数值模拟方法,针对不同主动射流方案对侧风状态下直升机着舰过程中的影响进行了分析。首先,采用分离涡模拟（DES）方法获得不同射流方案下的艉流场数据,随后,将艉流场数据通过单向耦合的方式与直升机飞行动力学模型耦合,得到直升机在着舰过程受到的气动载荷与操纵量变化。从非定常载荷水平与操纵特性的角度,分析不同主动射流方案对舰船艉流场的非定常特征的影响。结果表明:射流装置安装在机库迎风侧水平边缘及垂直边缘均可以有效抑制直升机着舰过程中的非定常载荷水平。其中,垂直边缘射流方案能够实现舰艉流非定常特征与空间特征的解耦,保持直升机操纵余量不会降低；水平边缘射流方案则会增大艉流场侧洗分量,降低脚蹬操纵余量。而随着射流速度增加,垂直边缘射流方案控制效果会不断降低；水平边缘射流方案控制效果会先增高后降低。

Abstract:

To improve the take-off and landing safety of shipborne helicopters, a numerical method based on one-way coupling strategy was developed for the study of ship-helicopter dynamic interface, with which the effect of different active flow control configurations on helicopter shipboard landing was analyzed under crosswind condition. First, the ship airwake data under different jet control conditions was obtained by using detached eddy simulation (DES). Then, the unsteady airloads and control margins during the shipboard landing were obtained by coupling the ship airwake data with the flight dynamics model. The effect of the active flow control at different locations on ship-helicopter dynamic interface under crosswind condition was investigated, in terms of unsteady loading levels and control characteristics of shipborne helicopter. Results show that the two active jet control configurations could both reduce the unsteady loading levels during the lateral translation of the helicopter. For the configuration that the jet outlet located at hangar vertical edge, the decoupling of unsteady characteristics and spatial characteristics could be realized, and the helicopter control margin was not reduced. While the configuration that the jet outlet located at the horizontal edge could increase the lateral velocity component of ship airwake and reduce the pedal margin. In addition, with the jet velocity increased, the control ability of jet decreased under the first configuration, and it increased first and then decreased under the second configuration.