共查询到19条相似文献，搜索用时 141 毫秒
1.
海况对水下运载器吊放回收的影响 总被引：1，自引：1，他引：1
本文将水下运载器，吊索和母船看作是一个由弹簧连接的单自由度系统，通过对系统进行分析和研究，建立了水下被吊物体在吊索带动下，由吊臂端点运动引起的运动响应的物理模型、数学方程，并编制了各项参数可调的计算机程序以求解水下物体的运动轨迹。运用此程序，对影响参数作系列变化后进行了运动响应计算，并绘制成运动响应随这些参数变化的曲线，为水下吊放回收系统的设计提供了依据 相似文献
2.
《中国海洋大学学报(自然科学版)》2017,(6)
针对近水面航行的欠驱动自主水下航行器(AUV),研究了其波浪力作用下的航向控制问题。首先,利用局部微分同胚将AUV非线性系统转换为Brunovsky标准型系统;其次,基于波浪力的Morison方程给出了波浪力干扰外系统模型;然后,根据最优控制理论,基于二次型性能指标设计欠驱动AUV系统的前馈反馈最优扰动抑制控制律,并通过求解Riccati方程和矩阵方程获得。最后,通过AUV系统仿真实例验证了该方法的有效性。 相似文献
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圆柱形沉浮式深海养殖网箱的受力分析 总被引：9，自引：0，他引：9
应用一系列力学关系，研究了深海圆柱形沉浮式养殖网箱所承受的波浪力情况。导出深海沉浮式养殖网箱的运动方程，并给出数值计算。在网箱波浪力的研究中采用绕射理论和Morison方程，讨论了在波高、波长及周期变化下水动力的变化趋势，得出网箱所受到的水平波浪力远大于竖直波浪力，波高的变化对波浪力的影响最大的结论，为深海网箱的设计校核提供1种参考方法。 相似文献
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水下运载器根据其使命,通常内部装载不同战斗载荷,其中上浮开盖过程是其作战流程中非常关键的一个动作过程,水下运载器在其工作过程中受到波浪力、火箭推力、重力、流体阻力等外界因素的影响,而开盖动作又使得水下运载器系统构件之间产生相对运动,其运动特性较为复杂.针对水下运载器系统,利用多刚体Kane方法建立了系统的动力学方程,利... 相似文献
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提出了在海浪对海岸作用过程中由于泥沙冲淤所造成的水下斜坡剖面演化的数学模式，导出了描述海底变形的方程。该方程属于非线性热传导方程一类。在确定边界条件时，曾考虑了对于给定的海浪状况下实际剖在对其均衡状态适应的程度。还介绍了在波浪原始参数和水下斜坡特征不同值时，海底由最初线性剖面的演变，指出理论预测的底形变化趋势与实测的底形变化趋势类似。 相似文献
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基于多体动力分析方法进行FPSO和水下软钢臂系泊系统的运动特性研究。相较于非线性弹簧模拟软钢臂系泊系统或者其他近似模拟方法,多体分析方法可以充分考虑系泊系统具体结构形式及其动力项对FPSO运动性能的影响,更好的预报系统运动响应和系泊力。本文将FPSO和水下钢臂结构模拟成2个具有6自由度的独立结构,两者用系泊链组进行连接。基于三维势流理论应用汇源分布法,首先在频域内进行FPSO的水动力参数分析,进而在时域内对系统进行耦合动力分析。本文重点讨论系泊系统黏性力和二阶波浪力对系统响应的影响,计算结果发现系泊系统黏性力对系泊力有一定影响,而在浅水条件下二阶波浪力的计算对准确预报系统运动及系泊力非常重要。 相似文献
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当安装于水下航行体上的旋转装置质量或转动惯量达到一定程度时,其对水下航行体运动与操纵的影响是不可忽略的。针对安装于水下航行体上的旋转装置,分析了水下航行体运动时装置的陀螺效应。得出了旋转装置陀螺力的明确数学方程。不失方法的一般性,假设旋转装置只在运动坐标系的X轴方向有旋转角速度,推导了在考虑陀螺效应作用的情况下水下航行体的六自由度模型方程;以此为基础,建立了水下航行体的仿真模型并对水下航行体的水下运动特性进行了仿真,分析了旋转装置的质量、角速度对水下航行体运动特性的影响规律,从而为研究在考虑陀螺效应情况下的水下航行体操纵奠定了基础。 相似文献
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波浪作用下异重流运动特性研究 总被引：3，自引：0，他引：3
本文通过水槽试验和理论分析手段对波浪作用下异重流运动特性进行了研究，应用流体运动基本方程推导了异重流在水平底面运动时的运动速度、厚度和流量表达式。结果表明，计算结果与水槽试验较一致 相似文献
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针对无限水深下波浪与二维水面物体相互作用问题,传统的波浪格林函数形式复杂、计算缓慢,为了提高计算效率和计算精度,将流域分为物体周围的内域及远离物体的外域,内域采用简单格林函数法,外域采用多极子展开方法,通过内外域边界匹配,耦合求解得到流域中任意一点的速度势,并可计算物体在波浪作用下的波浪激振力、附加质量、辐射阻尼及透射和反射系数。应用该方法计算了二维水面漂浮半圆和水面漂浮方箱的算例,数值计算结果表明,该方法可以方便、准确、快速地计算无限水深下波浪与任意漂浮物体的作用问题。 相似文献
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水下拖曳升沉补偿系统水动力数学模型研究 总被引：4，自引：2，他引：2
建立变缆长的水下拖曳升沉补偿系统水动力学偏微分方程组和边界条件.拖缆动力学模型基于Ablow and Schechter模型,拖体采用水下运载体六自由度方程模拟,运用有限差分法离散偏微分方程组和牛顿迭代法计算变缆长情况下拖体深度与拖缆各点张力的动态取值.数值计算结果表明采用收放拖缆的升沉补偿方法能够有效削弱母船升沉运动对拖体深度和拖缆张力的影响. 相似文献
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主动式声纳列阵拖曳系统姿态数值计算 总被引：2，自引：1，他引：2
主动式声纳列阵拖曳系统是用于探测潜艇的新型声纳系统，为了准确探测潜艇的位置，必须首先预报声纳列阵的瓷态，本文通过对其三维力学模型的分析，得到该系统的运动微分方程，其中缆索的力学方程是基于Ablow和Milinazzo的模型，而对于拖体则运用六自由度空间运动方程模拟，结合边界条件，用有限差分法求解，通过对拖船的不同运动状态如匀速，变速和回转的计算，证明本文的方法对于预报声纳列阵的姿态是有效的。 相似文献
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PETREL,a winged hybrid-driven underwater glider is a novel and practical marine survey platform which combines the features of legacy underwater glider and conventional AUV (autonomous underwater vehicle).It can be treated as a multi-rigid-body system with a floating base and a particular hydrodynamic profile.In this paper,theorems on linear and angular momentum are used to establish the dynamic equations of motion of each rigid body and the effect of translational and rotational motion of internal masses on the attitude control are taken into consideration.In addition,due to the unique external shape with fixed wings and deflectable rudders and the dual-drive operation in thrust and glide modes,the approaches of building dynamic model of conventional AUV and hydrodynamic model of submarine are introduced,and the tailored dynamic equations of the hybrid glider are formulated.Moreover,the behaviors of motion in glide and thrust operation are analyzed based on the simulation and the feasibility of the dynamic model is validated by data from lake field trials. 相似文献
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An integrated hydrodynamics and control model to simulate tethered underwater robot system is proposed. The governing equation of the umbilical cable is based on a finite difference method, the hydrodynamic behaviors of the underwater robot are described by the six-degrees-of-freedom equations of motion for submarine simulations, and a controller based on the fuzzy sliding mode control (FSMC) algorithm is also incorporated. Fluid motion around the main body of moving robot with running control ducted propellers is governed by the Navier–Stokes equations and these nonlinear differential equations are solved numerically via computational fluid dynamics (CFD) technique. The hydrodynamics and control behaviors of the tethered underwater robot under certain designated trajectory and attitude control manipulation are then investigated based on the established hydrodynamics and control model. The results indicate that satisfactory control effect can be achieved and hydrodynamic behavior under the control operation can be observed with the model; much kinematic and dynamic information about tethered underwater robot system can be forecasted, including translational and angular motions of the robot, hydrodynamic loading on the robot, manipulation actions produced by the control propellers, the kinematic and dynamic behaviors of the umbilical cable. Since these hydrodynamic effects are fed into the proposed coupled model, the mutual hydrodynamic influences of different portions of the robot system as well as the hydrological factors of the undersea environment for the robot operation are incorporated in the model. 相似文献
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For Cconsideration ofing both the eccentric rotatable rigid body and the translational rigid body, the dynamic model of the underwater glider is derived. Dynamical behaviors are also studied based on the model and can be used as the guidance to underwater gliders design. Gibbs function of the underwater glider system is derived first, and then the nonlinear dynamic model is obtained by use of Apell Equations. The relationships between dynamical behaviors and design parameters are studied by solving the dynamic model. The spiral motion, swerving motion in three dimensions and the saw-tooth motion of the underwater glider in vertical plane are studied. Lake trials are carried out to validate the dynamic model. 相似文献
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A three-dimensional model of a two-part underwater towed system is studied. In the model, the governing equations of cables are established based on the Ablow and Schechter method. The boundary conditions for the two-part underwater towed system are derived. The six-degrees-of-freedom equations of motion for submarine simulations are adopted to predict the hydrodynamic performance of a towed vehicle. The established governing equations for the system are then solved using a central finite difference method. In this paper several algorithms are used to solve this special form of finite difference equations. The results in this paper indicate that the two-part underwater towed system improves the dynamic behavior of the towed vehicle and is an easy way to decouple the towing ship motion from the towed vehicle. Because the model uses an implicit time integration, it is stable for large time steps and is an effective algorithm for simulation of a large-scale underwater towed system. 相似文献
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In this paper,the underwater vehicle,sling and the mother ship are considered as a single de-gree of freedom system connected by a spring.Through the analysis of this system,a physical model is es-tablished,which describes the motion of the vehicle caused by the ship motion and wave motion.Furthermore,a mathematical model based on this physical model is obtained,and a numerical solutionprogram is made.As an example,a practical launch and recovery system for an underwater robot is calcu-lated by use of the program.and the motion track of the robot is obtained. 相似文献
18.
Michio Ueno 《Ocean Engineering》2010,37(10):879-890
A submersible surface ship (SSS) is based on a novel concept that the SSS goes on surface like conventional ships in moderate seas but goes underwater in rough seas to the depth sufficient to avoid wave effects. The SSS has a wing system that produces downward lift to go underwater with preserving the residual buoyancy for its safety. The SSS is expected to be able to keep both safety and punctuality even if it encounters unexpected bad weather.The motion of the SSS is studied. The equations of motion are formulated and the procedures for estimating hydrodynamic derivatives are presented. The hydrodynamic derivatives are estimated for a SSS having a configuration, a hull with a pair of main wings and a pair of horizontal tail wings. Using these estimated hydrodynamic derivatives, calculation of the SSS motion is carried out.The calculation results show some specific aspects of the SSS especially for effects of the elevator of main wings and horizontal tail wings, aileron of main wings, rudder and propeller revolution. It is confirmed that the existence of static roll restoring moment and having large hull comparing with wing area play important roles in the motion of the SSS. 相似文献
19.
Nonlinear Random Motion Analysis of A Tension Leg Platform Considering the Set-down Motion of A Floating Body 总被引：1，自引：1，他引：0
The dynamic analysis of a Tension Leg Platform (TLP) in random wave is investigated by considering the set-down of a floating body. The nonlinear restoring stiffness is derived with the set-down motion of a floating body and the coupled motion of the tension leg and platform and the differential equations of the motion are established. The study focuses on the influence of the set-down motion on the nonlinear response of the platform. By considering different significant wave heights and currents, motion responses of the platform are calculated and compared. The analysis shows that the set-down motion significantly increases the heave motion with low frequency and the equilibrium position of the heave motion with the set-down motion is much lower than that without set-down motion. The results in this paper indicate that the set-down motion has a major impact on the safety of the platform inproduction operation, and it is also a threat to the strength of tension legs and risers. 相似文献