计及侧向流影响的自治水下航行器6-DOF运动仿真

发布时间：2019-04-19 12:26

【摘要】：自治水下航行器(AUV:Autonomous Underwater Vehicle)是一种在复杂海洋环境下执行勘探、探测、反鱼雷等任务的智能化平台,可较好的满足科研、军事、商业等需求。海洋环境瞬息万变,存在洋流、密度(温度、盐度)跃层、波浪等现象,对水下航行器的运动性能会产生重要影响,而AUV执行工作任务时多处于直航状态,因此分析AUV在受到各种侧向流干扰下的运动性能有重要意义和价值,并在此基础上计算AUV不同结构特征在侧向流干扰下的运动性能。最终结果可为其结构设计提供依据。本文利用计算流体力学的动网格技术提出了六自由度(6-DOF)仿真计算方法。具体研究成果如下:研究了AUV在无洋流干扰下的直航性能。建立其几何模型,在ICEM中划分四面体网格,导入FLUENT中进行有限元计算。基于6-DOF方法,通过加载UDF(User Defined Function)函数来赋予AUV的质量属性,通过设置合适的重浮心距离,成功实现了AUV的稳定直航运动。研究了AUV在侧向流干扰下的运动性能和粘性流场特性。结合采用RANS方程和标准k-?湍流模型,求解了AUV在侧向流干扰下的非定常粘性流场和位姿变化状况。仿真AUV在不同侧向流大小、不同侧向流方向的运动性能,通过分析AUV重心轨迹、姿态角、流体力、流体力矩以及压力云图、速度云图等,探讨了不同侧向流对AUV运动性能的影响。研究了具有不同结构特征的AUV在侧向流作用下的运动性能和位姿变化状况。当主体外形确定后,AUV的结构特征主要包括尾翼布局方式、尾翼安装位置、尾翼大小、不同重浮心距离分布。结果表明,X 45?-型尾翼分布方式在受到侧向流干扰时,可保持较好的运动性能;尾翼安装位置为L/L?=0.0736(L?为尾翼根部到AUV壳体末端的距离,L为AUV全长)时,AUV有相对良好的运动性能;尾翼过小时,会引起AUV的横滚、俯仰运动剧烈;不同重浮心距离的分布对AUV运动性能影响很大,是设计初期重要的考察因素。计算结果可为AUV结构设计、控制器设计等提供理论参考和依据。
[Abstract]:Autonomous underwater vehicle (AUV:Autonomous Underwater Vehicle) is an intelligent platform to carry out exploration, detection, anti-torpedo and other tasks in complex marine environment. It can meet the needs of scientific research, military, commercial and so on. The rapid change of marine environment, the existence of ocean currents, density (temperature, salinity) leaps, waves and other phenomena, will have an important impact on the performance of underwater vehicles, and AUV work in the direct state of most of the tasks. Therefore, it is of great significance and value to analyze the motion performance of AUV under the interference of various lateral flows. On this basis, the motion performance of different structural characteristics of AUV under the interference of lateral flow is calculated. The final results can provide the basis for its structural design. In this paper, a six-degree-of-freedom (6-DOF) simulation method is proposed by using the dynamic grid technique of computational fluid dynamics (CFD). The specific results are as follows: the direct navigation performance of AUV without ocean current interference is studied. Its geometric model is established, tetrahedral mesh is created in ICEM, and finite element calculation is carried out in FLUENT. Based on the 6-DOF method, by loading the UDF (User Defined Function) function to give the quality property of the AUV, the stable direct motion of the AUV is successfully realized by setting the proper distance of the center of gravity. The motion performance and viscous flow characteristics of AUV under lateral flow interference are studied. Combined with RANS equation and standard? The turbulent model is used to solve the unsteady viscous flow field and posture variation of AUV under lateral flow disturbance. The motion performance of AUV in different lateral flow size and direction is simulated. The center of gravity trajectory, attitude angle, fluid moment, pressure cloud and velocity cloud of AUV are analyzed. The influence of different lateral flow on the motion performance of AUV is discussed. The motion performance and posture changes of AUV with different structural characteristics under lateral flow are studied in this paper. When the shape of the main body is determined, the structural characteristics of the AUV mainly include the configuration of the tail, the installation position of the tail, the size of the tail, and the distance distribution of different gravity buoyancy centers. The results show that the X 45-type tail can maintain good motion performance when it is disturbed by lateral flow, and the position of tail installation is L/L?=0.0736 (L? For the distance from the root of the tail wing to the end of the AUV shell (L is the full length of AUV), the AUV has relatively good motion performance, and when the tail wing is too small, it will cause the roll of AUV and the pitch motion is intense. The distribution of different gravity center distance has a great influence on the motion performance of AUV, which is an important factor in the initial design. The calculation results can provide theoretical reference and basis for AUV structure design and controller design.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U674.941

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