水下机器人试航速度的类物理数值方法预报

Prediction of autonomous underwater vehicle cruising velocity using a physics-based numerical method

水下机器人试航速度是评价推进系统性能和续航能力的重要指标。针对水下机器人试航速度预报问题,本文提出类物理数值预报方法,建立水下机器人包含桨舵的全附体模型,采用多块动态混合网格方法进行网格构建和更新,编写用户自定义函数,求解六自由度方程和非定常雷诺平均NS方程进行水下机器人和螺旋桨力和速度的计算和传递,实现以螺旋桨旋转运动推进水下机器人自航的运动过程模拟。数值结果表明:水下机器人试航速度1.5 m/s对应的转速为570 r/min;自航模拟可见螺旋桨梢涡曳出,梢涡强度和螺旋桨推力随航速增加而降低。数值模拟再现了非定常运动过程中船桨舵相互作用机理,有利于水下机器人复杂操纵运动的精确预报。

The cruising velocity of an autonomous underwater vehicle(AUV) plays an important role in the evaluation of the thrust system performance and cruising endurance. This study proposed a physics-based numerical method for the prediction of the cruising velocity of the AUV. The full model of the AUV appended propeller and rudder was built. A multi-block hybrid dynamic grid method was used to mesh and re-mesh the domain. User-defined functions were programmed. Six degrees of freedom and unsteady Reynolds-averaged Navier-Stokes equations were solved to transfer forces and velocities between AUV and propeller. Thus, the free motion of the AUV pushed by the rotating propeller from stationary to uniform velocity was simulated. The numerical results showed that the rotating speed was 570 r/min at the cruising velocity of 1.5 m/s. The tip vortices were produced in self-propulsion motion. The strength of the tip vortices and propeller thrust decreased with the increase in the AUV velocity. The simulation investigated the unsteady flow field among the hull, propeller, and rudders in detail, which is helpful in conducting a precise maneuvering prediction of the AUV in complex environments.