共查询到18条相似文献,搜索用时 265 毫秒
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利用超空泡技术来突破水下航行器的速度屏障.超空泡航行器在水下运动时,其大部分表面被超空泡包裹,构成了一种新的流体动力布局,运动模式完全不同于常规航行器,其受力状态也极其复杂.为了进一步分析超空泡流场中航行器受力特性,先描述了超空泡形态,分析影响超空泡变形的主要因素,然后对超空泡流场中的航行器出现的流体动力进行分析,并且对流体动力进行线性处理.本研究结果有利于航行器运动特性分析. 相似文献
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通气超空泡内部流场的PIV实验图像处理 总被引:1,自引:0,他引:1
PIV测试是流体动力学实验研究的重要方法之一,可以成为通气超空泡内部流场结构实验研究的有效手段。通过水洞实验利用PIV对通气超空泡内部流场进行测试时,激光在气液两相界面处会发生折射,导致实验图像变形和失真。文章分析了激光在空化流场中各相界面的折射特性和PIV实验图像的变形规律;在此基础上,推导了图像变形的分析计算式,给出了通过原始流场图像获取真实流场图像的还原处理方法;编制了图像还原计算程序,并对原始PIV图像进行了处理,得到了反映真实空泡内部流场结构的图像。 相似文献
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超高速航行器在水下运动时,其大部分表面被超空泡包裹,构成了一种新的流体动力布局,运动模式和运动特性完全不同于常规水下航行器。为了分析超高速水下航行器运动的稳定性,本文对超空泡生成机理进行研究,给出描述超空泡形态的数学模型,得到不同影响因素作用下超空泡形态的变化规律。为验证超空泡实时生成效果和超高速水下航行器运动过程各种动作功能,采用Vega Prime构建三维虚拟环境,在此基础上设计超空泡视景演示系统,通过ADI仿真系统实时解算超空泡和水下航行器运动数据来驱动超空泡视景系统,逼真地演示超空泡动态生成过程以及水下航行器高速运行轨迹和“空泡+航行器”的相对运动关系等关键技术。 相似文献
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《舰船科学技术》2016,(17)
超高速航行器在水下运动时,其大部分表面被超空泡包裹,构成了一种新的流体动力布局,运动模式和运动特性完全不同于常规水下航行器。为了分析超高速水下航行器运动的稳定性,本文对超空泡生成机理进行研究,给出描述超空泡形态的数学模型,得到不同影响因素作用下超空泡形态的变化规律。为验证超空泡实时生成效果和超高速水下航行器运动过程各种动作功能,采用Vega Prime构建三维虚拟环境,在此基础上设计超空泡视景演示系统,通过ADI仿真系统实时解算超空泡和水下航行器运动数据来驱动超空泡视景系统,逼真地演示超空泡动态生成过程以及水下航行器高速运行轨迹和"空泡+航行器"的相对运动关系等关键技术。 相似文献
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为了探索通气超空泡的生成机理和获取形态可控有效减阻的超空泡,文章利用中速可持续通气空泡水洞进行了空化器和通气联合生成超空泡的实验研究.详细分析了通气超空泡的生成和发展过程;给出了空化器直径、空化器线形对通气系数门限值和通气超空泡形态的影响.研究表明,在相同条件下,较大直径空化器模型形成通气超空泡需要的通气系数门限值较低,相应的超空泡尺寸也较大;平头倒角形和圆盘形空化器比圆锥形的形成通气超空泡需要的通气系数门限值低,相同条件下前者形成的超空泡尺寸也较后者大;对于圆锥形空化器,锥角较小的不易形成通气超空泡.文中实验研究结果为水下航行体的空化器合理设计提供了重要的参考依据. 相似文献
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采用两流体模型以及DES湍流模型对通气超空泡发展过程以及泡内压力变化规律进行了三维数值仿真。模拟了两种泄气方式:回注射流和双涡管泄气方式。并基于文中数值方法预测通气超空泡方面的能力,对两种研究航行体滑行状态的方法进行了评估:一种方法是在水槽中的定轴俯仰运动,另一种方法是类似于约束模实验的自由俯仰运动,两种方法都采用了网格变形技术。结果表明在相同条件下,后者可以很容易得到超空泡航行体的滑行状态而前者较难获取滑行状态,尽管在水槽中前者更易实现。文中的数值方法可以用来进一步研究滑行状态并给出一些有意义的结论。 相似文献
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基于势流理论、细长体理论和奇点分布法,对水下发射过程中的航行体空泡、自由面和筒口气团的相互影响开展了理论研究。文中用一个奇点模拟气团、用沿轴线分布的奇点模拟细长体形状的航行体和空泡,建立了自由面影响下的气团和空泡相互耦合的动力学模型,提出了非定常流场中带气体泄漏现象的含气空泡的压力估算方法。实验结果验证了文中提出的模型的合理性。 相似文献
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Eduard Amromin 《船舶与海洋工程学报》2018,(2)
Bottom ventilated cavitation is the successfully proven ship drag reduction technology, but the impact of sea waves on ships with bottom cavities is the substantial concern for a broad technology implementation. The influence of waves on vertical force experienced by such ships is analyzed in this paper using a perturbation technique. The unperturbed cavity shape at given Froude number and cavity length was found from a nonlinear steady ideal fluid problem. The ship response to an impact of a wave of the given length and amplitude is considered as the one-frequency perturbation. This perturbation was found by combined consideration of compressible flow in the cavity and incompressible flow in the surrounding water. Computational examples relate to an earlier tested model with the bottom cavity restricted by skegs. The vertical forces on the model with bottom cavities and in cavitation-free conditions were compared in head and following seas. It was found that within the major part of the consider range of wavelengths the cavity acts as a shock absorber significantly reducing the vertical force pulsation and ship acceleration in waves. 相似文献
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Eduard Amromin 《船舶与海洋工程学报》2018,17(2):173-177
Bottom ventilated cavitation is the successfully proven ship drag reduction technology, but the impact of sea waves on ships with bottom cavities is the substantial concern for a broad technology implementation. The influence of waves on vertical force experienced by such ships is analyzed in this paper using a perturbation technique. The unperturbed cavity shape at given Froude number and cavity length was found from a nonlinear steady ideal fluid problem. The ship response to an impact of a wave of the given length and amplitude is considered as the one-frequency perturbation. This perturbation was found by combined consideration of compressible flow in the cavity and incompressible flow in the surrounding water. Computational examples relate to an earlier tested model with the bottom cavity restricted by skegs. The vertical forces on the model with bottom cavities and in cavitation-free conditions were compared in head and following seas. It was found that within the major part of the consider range of wavelengths the cavity acts as a shock absorber significantly reducing the vertical force pulsation and ship acceleration in waves. 相似文献
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The most complicated component in cavitating flow and pressure distribution is the flow in the cavity closure line. The cavitating flow and pressure distribution provide critical aspects of flow field details in the region. The integral of pressure results of the hydrodynamic forces, indicate domination in the design of a supercavitating vehicle. An experiment was performed in a water tunnel to investigate the pressure characteristics of the cavity closure region. Ventilation methods were employed to generate artificial cavity, and the ventilation rate was adjusted accordingly to obtain the desired cavity length. An array of pressure transducers was laid down the cavity closure line to capture pressure distribution in this region. The experimental results show that there is a pressure peak in the cavity closure region, and the rise rate of pressure in space tends to be higher in the upwind side when the flow is non-axisymmetric. The transient pressure variations during the cavity formation procedure were also present. The method of measurement in this paper can be referenced by engineers. The result helps to study the flow pattern of cavity closure region, and it can also be used to analyze the formation of supercavitating vehicle hydrodynamics. 相似文献