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B.H.型气泡高速艇规则波中纵向运动试验研究 总被引:1,自引:0,他引:1
在高速拖曳水池里开展了B.H.型气泡高速艇静水阻力及规则波纵向运动模型试验,研究了气流量、航速、波长、波高等因素变化对B.H.艇波浪中阻力、垂荡、纵摇、垂向运动加速度的影响。探讨了波高变化对饱和气流量的影响。研究结果表明:静水中B.H.艇相对减阻率可达36.25%,绝对减阻率可达20.79%,迎浪规则波中相对减阻率可达32.3%,与静水减阻效果基本相当,波长变化对减阻率的影响甚微。气层并未导致纵向运动性能的恶化,相反在一定航速与波长范围内,艇底气层能改善垂荡与纵摇运动;饱和气流量下,阻力、垂荡、纵摇及重心垂向运动加速度随波高呈非线性变化,航速增大非线性增强,波长增加非线性降低;波浪中饱和气流量随波高呈非线性变化。 相似文献
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采用基于三维时域Rankine源方法的水动力分析软件Wasim,对某小水线面双体科考船在不同航速、不同海况与不同浪向下的耐波性进行了计算与分析,重点对不同工况下小水线面双体船横摇、纵摇和垂荡性能进行了研究.研究表明:无航速时,横摇有义单幅值极大值出现在90°浪向,纵摇极大值出现在0°与180°浪向;较高航速时,横摇响应最大单幅值出现在60°与90°浪向,纵摇在30°,150°和180°浪向时明显较大;波浪对连接桥的砰击会显著影响SWATH船的运动响应,使垂荡运动幅值显著增大;随航速的提高,顺浪航行下纵摇运动幅值逐渐减小. 相似文献
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顶浪规则波中小水线面双体船纵向运动特性数值分析 总被引:1,自引:0,他引:1
基于RANS方程和VOF模型求解船体粘性兴波流场,采用Overset技术处理船体运动,开展了小水线面双体船(Small Waterplane Area Twin Hulls,SWATH)迎浪规则波中运动响应特性及其产生机理的研究.通过数值计算结果与模型试验结果的对比分析,验证了本文方法的有效性;在此基础上,分析了船体运动响应曲线中各峰值产生的原因及片体间相互干扰对SWATH船在波浪中运动响应的影响,发现其中一个峰值出现的原因为遭遇频率接近船体运动固有频率,由此发生共振;另一个峰值的出现则可能与SWATH特殊的船型及附体配置有关.由于SWATH船片体间的水动力干扰效应,SWATH船在波浪中运动响应峰值较单个片体响应峰值明显减小,且出现的位置向低频方向移动. 相似文献
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国际海事组织(IMO)船舶设计建造分委会(SDC)第4次会议把过度加速度稳性直接评估的制定提上议程。然而,如何准确预报和评估波浪中的过度加速度依然是一个亟待解决的问题。文章针对此挑战,采用三维时域混合源法进行了波浪中过度加速度的直接预报和评估。首先,采用三维时域混合源法,建立了波浪中船舶大幅横摇运动和船体任意位置处横向加速度的非线性时域预报方法;其次,以4000TEU集装箱船为研究对象,开展规则波和不规则波中的大幅运动模型试验,对计算方法进行验证;然后,对比分析了3DOF(垂荡—纵摇—横摇)和4DOF(横荡—垂荡—纵摇—横摇)耦合数学模型的计算精度;最后,分析了船体横向加速度的影响因素。研究表明,考虑横荡影响的4DOF数学模型计算精度较高;数值计算结果和模型试验结果吻合良好,证明文中建立的非线性时域方法可有效预报波浪中的过度加速度,可用于IMO过度加速度衡准的制定,也可为船舶设计提供评估手段。此外,文中还研究了IMO薄弱性衡准草案中中国和德国联合提出的加速度简化计算方法的适用性,证明该简化计算方法具有一定的保守性,符合衡准的要求,可用于过度加速度薄弱性衡准计算。 相似文献
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《舰船科学技术》2016,(15)
基于RANS方程和VOF模型求解船体粘性兴波流场,采用Overset技术处理船体运动,开展了小水线面双体船(Small Waterplane Area Twin Hulls,SWATH)迎浪规则波中运动响应特性及其产生机理的研究。通过数值计算结果与模型试验结果的对比分析,验证了本文方法的有效性;在此基础上,分析了船体运动响应曲线中各峰值产生的原因及片体间相互干扰对SWATH船在波浪中运动响应的影响,发现其中一个峰值出现的原因为遭遇频率接近船体运动固有频率,由此发生共振;另一个峰值的出现则可能与SWATH特殊的船型及附体配置有关。由于SWATH船片体间的水动力干扰效应,SWATH船在波浪中运动响应峰值较单个片体响应峰值明显减小,且出现的位置向低频方向移动。 相似文献
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迎浪规则波中波浪增阻和船体垂向运动的数值预报(英文) 总被引:1,自引:0,他引:1
The numerical prediction of added resistance and vertical ship motions of one ITTC (International Towing Tank Conference) S-175 containership in regular head waves by our own in-house unsteady RANS solver naoe-FOAM-SL JTU is presented in this paper. The development of the solver naoe-FOAM-SJTU is based on the open source CFD tool, OpenFOAM. Numerical analysis is focused on the added resistance and vertical ship motions (heave and pitch motions) with four very different wavelengths (0.8Lpp≤λ≤1.5Lpp) in regular head waves. Once the wavelength is near the length of the ship model, the responses of the resistance and ship motions become strongly influenced by nonlinear factors, as a result difficulties within simulations occur. In the paper, a comparison of the experimental results and the nonlinear strip theory was reviewed and based on the findings, the RANS simulations by the solver naoe-FOAM-SJTU were considered competent with the prediction of added resistance and vertical ship motions in a wide range of wave lengths. 相似文献
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深V型滑行艇纵向运动试验研究 总被引:7,自引:1,他引:6
深V型滑行艇模型纵向运动试验研究表明:规则波中,升沉响应的平均值与静水航行时的重心升高极为接近,纵摇响应的平均值与静水航行时的纵倾较为接近,证实了相同航速下滑行艇在波浪中航行的纵向运动是相对于静水浮态的升沉纵摇运动;随着航速的增加,升沉响应峰值、纵摇响应峰值、垂向运动加速度峰值都向长波方向移动;速度较高、波幅较大时,升沉、纵摇、垂向运动加速度是非线性的。 相似文献
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Forng-Chen Chiu Wen-Chuan Tiao Jenhwa Guo 《Journal of Marine Science and Technology》2007,12(4):203-217
It is well known that the hydrodynamic responses of a high-speed vessel traveling in regular head waves of even moderate wave
height can show significant nonlinear behavior, and so linear statistical techniques become insufficient for predicting the
statistics of responses in irregular waves. On the other hand, it has been shown that an approximate third-order Volterra
model is applicable to handling the statistics of some nonlinear seakeeping problems, such as motions and vertical hull girder
loads. In the present study, the focus is on the nonlinear behavior of the pressure responses of the hull surface, especially
on the pressures acting on alternately wet and dry areas near the waterline and on the bow zone with high deadrise angles
that may be subject to slight impact and water pile-up effects. To clarify the validity of applying Volterra modeling to this
problem, a series of experiments in regular and irregular head waves were carried out, and approximate third-order and fifth-order
Volterra models with the proposed algorithm for finding frequency response functions (FRFs) were applied as a means of validation.
In the present article, the first part of the validation was performed using experimental data in regular waves. It was confirmed
that the third-order Volterra model has adequate accuracy to simulate deterministically the variation of pressure responses
in regular waves of different wave steepness up to a wave amplitude to wavelength ratio of 0.01 even for the highly nonlinear
pressures acting on the above-mentioned areas of the hull surface. 相似文献
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A nonlinear time-domain procedure is presented which is used to calculate the vertical responses of a container ship advancing
in head waves. The method assumes linear radiation forces represented by time convolution of memory functions, infinite frequency
added masses, and radiation restoring coefficients. The nonlinear hydrostatic restoring and Froude–Krilov forces are computed
exactly over the instantaneous wetted surface of the ship's hull. Forces due to green water on deck are calculated using the
momentum method. Nonlinear effects are identified on different vertical ship responses, namely on the heave and pitch motions,
the vertical accelerations, and the vertical bending moment. These non-linear effects are expressed by the variation of the
transfer function with the wave amplitude, the higher-order harmonics of the time signals, the offset of the time series,
and the asymmetry of the peaks. The numerical results and the quantified nonlinear effects are compared with experimental
results showing an ability to reproduce the main nonlinear effects.
Received: December 17, 2001 / Accepted: January 31, 2002 相似文献
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[目的]主动控制T型翼对船舶有着较好的纵向运动减摇效果,但最佳的T型翼主动控制策略仍未有定论,因此需对T型翼主动控制策略进行研究计算与分析。[方法]首先,采用细长体理论对Wigley III船型在不同波长规则波中的纵向运动响应进行数值计算;然后,在相同航速与波浪工况下,对加装了主、被动T型翼的船舶纵向运动进行数值预报,分析不同主动控制策略的减摇效果。[结果]计算结果显示:T型翼被动控制在共振区具有较好的减摇效果,长波区和短波区的减摇效果相对有限;纵摇角速度信号控制对纵摇运动和艏部运动加速度的减摇效果非常显著,但对于长波区的垂荡运动会有减益效果;船艏部运动速度信号对纵摇运动和艏部运动加速度的减摇效果较纵摇角速度信号均有10%~20%的提升,并且对垂荡运动的减摇效果也有一定提升。[结论]对于T型翼的主动控制,艏部运动速度信号控制综合考虑了纵摇与垂荡这2种运动,可以实现更好的减摇效果。 相似文献