【作者】 王宇；

【导师】 金鸿章；

【作者基本信息】 哈尔滨工程大学 ， 控制理论与控制工程， 2008， 博士

【摘要】 船舶在风浪中不可避免地会产生各种摇荡,其中以横摇最为显著,影响也最大。船舶在系泊或低航速状态下,当涌浪周期接近船舶自然横摇周期时,船舶摇摆比航行时更为剧烈。然而,只有船舶的航速较高时,常规减摇鳍才可以有效地减摇;船舶在低航速或零航速情况下,由于流过鳍表面的水流速度为零,鳍上升力也将消失,因而此时减摇鳍几乎不能进行减摇。对于在低航速或系泊状态下仍需要减摇的船舶来说,传统的减摇鳍就不再适用了。随着船舶减摇技术的发展,人们对系泊状态时船舶的减摇能力提出了新的期望。而减摇水舱减摇能力有限,有时甚至出现增摇现象。在减摇领域,零航速减摇鳍技术开发成为人们关注的问题,于是人们提出了零航速减摇鳍的概念。论文来源于国家自然科学基金项目“零速下船舶仿生减摇鳍升力机理的研究(50575048)”,主要研究内容是基于仿生流体力学研究在零来流流场中,依靠减摇鳍主动摆动产生升力的机理,建立船舶零航速仿生减摇鳍的升力模型。论文在广泛调研国内外仿生流体研究包括昆虫、鸟类飞行和鱼类巡游推进机理的理论研究、实验研究、数值模拟和模型研制的基础上,把零航速减摇鳍升力产生模式与昆虫悬停、鸟类飞行及鱼类摆动鳍、尾推进模式作为研究对象,采用理论分析、仿真计算和数值模拟相结合的研究方法,建立了可变弦长Weis-Fogh减摇鳍升力模型和单鳍仿生翼纵摇耦合升沉零航速减摇鳍升力模型;论证了两鳍片间的间隙对Weis-Fogh减摇鳍升力特性的影响;定义了升力对间隙的敏感因子的概念;得出了间隙对减摇鳍弦长的无量纲因子不大于10时间隙对升力影响不大的结论,该结论可以做为实际设计中的参考。论文深入分析了所提出的两种零航速减摇鳍的运动特征和力学机理,结合船舶减摇控制技术,将升力控制引入船舶零航速减摇鳍控制系统中,进一步引入能量限制建立了船舶零航速减摇鳍控制系统。采用仿真分析和数值试验的方法,对可变弦长Weis-Fogh减摇鳍升力模型在不同运动规律下的升力特性进行了研究,结果表明鳍片在一定张开规律下,通过弦长的动态变化,可以达到根据不同海浪周期,提供给船舶不同特性的升力的目的,所建模型能够反映在零速流场中的升力特性。单鳍仿生翼零航速减摇鳍升力模型是基于在非定常流场中对经典叶素理论进行修正,根据库塔-儒科夫斯基假设和船舶操纵性研究中广泛应用的“缓慢移动”假说而建立的。从仿真研究结果可看出,随着各种运动参数如减摇鳍纵摇和升沉幅值、频率、相位角等的不同,升力特性也不同,但纵摇对升力的影响占主要地位,纵摇和升沉两种运动的相位角为45°时升力较大。近年来,升力控制一直是船舶减摇技术的热点,将其引入船舶零航速减摇系统无疑是对船舶零航速减摇的又一发展。通过升力反馈和升力限位,对原有减摇鳍随动系统进行改进,建立了升力控制的船舶零航速减摇鳍控制系统。在不同海情90°浪向下的仿真研究结果表明,零航速减摇效果达到了60%以上,较减摇水舱不足50%的减摇效果有了很大提升。这说明建立的仿生减摇鳍升力模型和控制系统能够满足船舶零航速减摇的需要。更多还原

【Abstract】 Ships that were tossed by stormy waves are inevitable, among which roll is marked and severest. The roll is increased and severer than shipping state when the frequency of wave is similar as the natural rolling frequency of ships. Nevertheless, the traditional fin stabilizers could only anti rolling ship at higher ship speed effectively and the fin stabilizers could barely anti rolling ship at lower navigating speed or at anchor. The lift of fin would vanish at anchor. Because the speed of water flow across the surface of fin stabilizers is zero on this condition. The traditional fin stabilizers would not be applicable for the ships which still need anti rolling at lower speed or at anchor. New expectation of capability of anti roll ship is put forward with the development of ship roll stabilization. Anti roll capacity of anti rolling tank is limited, furthermore, sometimes the phenomenon of increasing rolling occurred. In ship anti roll field, the technology of ship roll stabilization at zero forward speed that becomes a focus and so the concept of anti roll ship at anchor is proposed.The dissertation is based on the project supported by national science foundation of China: research on lift theory of ship bionic roll stabilization at zero speed (50575048). Main research area is that based on the bionic hydrodynamics, the mechanism of lift produced by swaying the fin actively in the zero speed flow field is researched and the lift model of bionic fin stabilizers is established at anchor.In the dissertation, on the basis of extensive investigation and study on the bionic hydrodynamics such as theory, experiment, numerical calculation and model developed of insect and bird flight, fish cruising mechanism, the lift produced pattern of zero speed fin stabilizer, insect hovering, birds flight, the boost pattern of fish sways the pectoral fin and tail are researched, the lift model of variable chord Weis-Fogh fin stabilizers and lift model of single-bionic zero speed fin stabilizers are built with the complex method of theoretical analysis, simulation and numerical calculation, the influence of lamina clearance on characteristics of lift is demonstrated, the sensitive factor of lift on the lamina clearance is defined. The conclusion that lift is not influenced by clearance when non-dimensional factor of clearance on fin chord is less than 10 is obtained, this conclusion could be referenced in practical design. The movement characteristics and mechanical mechanism of the proposed two kinds of zero speed fin stabilizers are thoroughly analyzed and the lift control is induced into fin stabilizers control system at zero speed combined the technology of anti rolling ship, and the control system of fin stabilizers with energy restricted at anchor is established.By the methods of simulation analysis and numerical experiment, the lift characteristics of variable chord Wes-Fogh lift model with different motion law is researched and the results indicate that the different lift characteristics could be provided for ship according to different wave periods by dynamical changing chord length at stated fling law, the lift model proposed could be able to reflect the lift characteristic in still flow field.According to Kutta-Jucowski and "slowly moving" hypothesis that is extensive applied in the research of ship maneuvering, lift model of single-bionic zero speed fin stabilizers is built on the basis of revision to classical blade-element theory in unsteady flow field. The simulation results show that the characteristics of lift is different with the different motion parameters such as pitching angle and heaving amplitude, frequency and phase angle between pitch and heave. The pitching played a major role to lift of fin stabilizers. The lift is larger at 45°phase angle between pitch and heave.In recent years, lift control is always the point of anti roll ship, it is undoubtedly another development to introduce lift control to ship roll stabilization at zero forward speed. According to lift feedback and lift limit, the original servo system of fin stabilizers is improved and lift control system of zero speed fin stabilizers is established. The simulation results of 90°wave direction and different sea conditions indicate that effectiveness of anti rolling ship at zero speed is over 60% and much greater than anti roll tank whose effectiveness is less than 50%. It shows that the lift model of bionic fin stabilizers and control system could be able to satisfied the need of ship roll stabilization at zero forward speed.更多还原