【作者】 邢彦江；

【导师】 张嘉钟；

【作者基本信息】 哈尔滨工业大学 ， 一般力学与力学基础， 2013， 博士

【摘要】 超空泡减阻技术是实现水下航行体高速航行的有效途径，具有广阔的应用前景。航行体运动稳定性是保障航行体有效、准确的重要先决条件之一。而空泡流非定常特性对航行体流体动力以及运动稳定性具有显著影响。因此，必须对非定常空泡流流体动力开展进一步研究，从而为超空泡减阻技术的广泛应用及改进提供必要的依据。非定常空泡流影响因素较多，如通气不稳定性、物体运动状态变化、外界流场扰动等，国内外学者对此开展大量的研究，但多通过试验手段对空泡流非定常特性进行研究，采用数值方法对空泡流非定常特性研究多针对简单的物理模型如空化器、水翼，在几何结构上和实际水下航行体相距甚远。此外，对非定常空泡流研究多基于势流假设。考虑到航行体平衡多是通过改变舵面控制力与矢量推力实现，因此本文采用试验研究和数值研究相结合的方法对空化器转动、航行体水平尾翼运动、航行体变速运动、与航行体俯仰运动过程非定常空泡流空泡形态与航行体流体动力特性进行研究，在此基础之上，结合航行体运动方程与空泡流控制方程，给出能够准确预测超空泡航行体姿态与弹道的数值模拟方法。本文主要研究内容如下：基于均质平衡流理论，对比分析了采用多相流模型、湍流模型、空化模型计算非定常空泡流的结果，并基于试验结果选取了合理的数学模型与计算方法。利用通气空泡水洞开展了试验研究，得到了空化器攻角在非定常流场条件下，通气空泡形态与流体动力特性的影响规律。结合试验研究结果，采用数值模拟的方法研究了局部空泡和超空泡状态下航行体空化器转动对非定常空泡流空泡形态与航行体流体动力特性影响。采用人工通气的方法，针对超空泡航行体尾翼进行了水洞试验研究，分析了水翼楔形角对空泡形态与流体动力影响。同时，利用数值模拟的方法研究了水平尾翼安装位置、弹出过程及其攻角等因素对非定常空泡流流体动力的影响。采用相对运动方法，设定来流速度时间函数，实现航行体变速运动数值模拟；基于达朗贝尔原理，对流体相对运动方程进行推导，同时考虑到动坐标系牵连作用，采用流体相对运动方程代替CFD动量方程（N-S方程），提高了数值模拟精度。分别对自然空化与通气空化状态下航行体变速运动过程中的空泡形态变化及流体动力特性进行了系统研究，得到了自然空化航行体加速度与空泡形态滞后时间的关系，通气空化空泡形态脉动特性。通过数值模拟对航行体在俯仰运动过程中的超空泡流场进行了研究，得到了俯仰角速度、周期等因素对非定常空泡流流体动力的影响。通过理论推导，得到了航行体相对与地面坐标系下运动方程，结合udf二次开发，实现航行体运动方程与空泡控制方程耦合求解，建立了航行体纵平面内姿态与无控弹道的数值计算模型，得到了航行体质心位置对航行体减速运动航行体纵平面姿态与无控弹道的影响规律，为进一步对航行体弹道研究提供参考。更多还原

【Abstract】 Supercavitation drag reduction is an effective way for realizing high-speedmoving of underwater vehicle, and this technology has a broad applicationprospect. Motion stability of the underwater vehicle is one of the importantpreconditions to insure the vehicle security. The unsteadycharacteristic of cavityflow has significant effect on hydrodynamics and motion stability of the vehicle.Therefore, it is necessary to research the hydrodynamics of the unsteady cavityflow in order that the supercavitation drag reduction can be improved andapplied.There are many influencing factors on the unsteady cavity flow, such as theinstability of ventilation, the change of the vehicle’s motion state, external flowfield disturbance and so on. Domestic and overseas scholars have manypublications on it, but many researches on the unsteady characteristic of thecavity flow are experimental methodology. And the numerical methods about theunsteady characteristic of the cavity flow mainly aim at simple physical models,such as cavitator and hydrofoil. These models are far cry from the realunderwater vehicle in geometrically. In addition, the researches abouttheunsteady cavity flow are generally based on the potential flow assumption.Considering the stability of the vehicle is realized by changing the control forceof control surface and the thrust vector, experimental and numericalmethodologiesare used to study the cavitator rotation, hydrofoil motion, variablemotion, pitching motion and the hydrodynamics of theunsteady cavity flow. Onthis basis, combining the equations of motion of the vehicle and the equations ofcontrol of the cavity flow, a numerical simulation method is presented toforecast the attitude and trajectory of the vehicle with supercavitation. The mainworks of this paper are as follows:Based on homogeneous equilibrium flow theory, the numerical results ofthe unsteady cavitation flow are calculated by using multiphase flow model,turbulence model and cavitation model. The rational mathematical model andnumerical method are selected by comparing numerical results with experiment.Water tunnel experiments are conducted to study characteristics ofventilated supercavitation. The influence of the attack angle of cavitatoronventilated cavity and hydrodynamicsare studied. Combining experimental results,numerical simulations are performed to research the influence of cavitatorrotation of the vehicle on the hydrodynamics of the unsteady cavity flow in thelocal cavity and supercavitation states.Adopting the method of artificial ventilation, the water tunnel experimentsaiming at the hydrofoil of the vehicle with supercavitation are performed,and theinfluence of hydrofoil wedge angle on cavity shape and hydrodynamicsareanalyzed. In addition, using numerical simulations, the influence of hydrofoilposition, hydrofoil eject, hydrofoil attack angle on the hydrodynamicsof theunsteady cavity flow are studied.By adopting the method of relative movement, setting the time function of inflow velocity, numerical simulations are performed to realize the variablemotion of the vehicle. Based on d’Alembert principle, equations of fluid relativemotion are derived. Considering the convected effect of non-inertial coordinatesystem, the equations of fluid relative motion are used to replace the N-Sequations, and the accuracy of numerical simulations is improved. Cavitationmorphology changes and hydrodynamics of the vehicle’s variable motionprocess are studied in the natural cavitation and ventilated cavitation states, andthe relationship between natural cavitation acceleration of the vehicle and thetime lag of cavity form.Numerical simulations are performed to study the supercavitation flow fieldin the pitching motion process of vehicle, and the influence of the pitchingangular velocity and cycle on the hydrodynamics of theunsteady cavity flow isobtained.The equations of motion of the vehicle relative to the ground coordinatesystem are obtained by using theoretical derivation. Coupled solutions of themotion equations of the vehicle and the control equations of cavitation aresolved by using UdF secondary development. Numerical model of thelongitudinal plane attitude and free-flight trajectory of the vehicle is established.更多还原