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船舶螺旋桨空泡噪声研究 总被引:4,自引:0,他引:4
从空泡运动机理、数值计算方法及试验研究三方面对船舶螺旋桨空泡噪声最新的研究动态作了简单回顾.理论方面给出Rayleigh方程的应用范围;数值计算方面,将FWH方程方法应用于船舶螺旋桨噪声计算.结合所做试验,考虑了水中含气量对船舶螺旋桨空泡噪声的影响.同时对进一步需要开展的螺旋桨空泡噪声工作进行了展望. 相似文献
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文章针对定常可压缩泡状流中回转体的空化绕流进行了数值模拟,在给定来流速度和环境压力的条件下,对不同含气率下的空化与激波的相互作用进行了研究。首先,对含气率为0的情形进行计算并同试验数据进行对比,证明所采用的计算模型是可信的。其次,改变流场含气率从0至0.5进行计算,结果表明,随着含气率的增大,流场的可压缩性随之增强,体现为数值模拟得到了回转体绕流流场的3种波系,包括回转体头部处的脱体激波、分离面处的膨胀波和空泡尾端的斜激波。而空化与激波的相互作用则体现为:头激波削弱了空化效应,使得空化区域减小;由于空泡外形的影响,使得空泡尾端出现了斜激波;含气率超过一定值,空泡已经无法闭合在物面上,而是闭合在空泡尾端的激波面上,体现为空泡尾端壁面逆压梯度趋于平缓。计算结果揭示了泡状流中空化与激波相互作用的新的物理现象。 相似文献
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以PPTC(Potsdam Propeller Test Case)桨为研究对象,探索了螺旋桨梢涡及梢涡空泡的数值模拟方法。通过梢涡区域的划分及网格加密,对螺旋桨无空化流场进行了数值模拟,成功捕获了梢涡;然后基于均质混合流模型和Zwart-Gerber-Belamri空化模型对空化流场进行了数值模拟;并将计算结果与试验数据进行了广泛的比较和分析,以校验计算网格和计算方法。研究表明:无论片空泡还是梢涡空泡的计算结果均与试验观测吻合良好;同时,所得螺旋桨推力和扭矩系数也与试验值符合良好;有效地实现了梢涡捕捉及梢涡空泡模拟。同时指出,水中含气率对推力和扭矩系数的影响大于空泡形态。 相似文献
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本文提供了亚音速叶栅S1流面流函数多种例题的数值计算方法。各种命题相应的边界条件通过连续方程用流函数来表示,使得各种命题数值计算有相类似的数值迭代并统一在同一程序之中。 相似文献
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文章采用Sauer空化模型,研究了网格类型和湍流模型对均流中螺旋桨梢涡空泡数值模拟的影响,研究表明,现有的空泡模型适合于螺旋桨梢涡空泡的数值模拟,其中梢涡空泡区域网格密度是关键,文中提出了一种合适的梢涡空泡区域网格加密方法.对PPTC螺旋桨全湿流和梢涡空泡进行了数值预报,螺旋桨梢涡空泡形态与试验结果进行了对比,并应用涡判据"Q准则"和"λ2准则"分析了梢涡与梢涡空泡的流动特征.全湿流中梢涡区域的涡量随周向的分布呈现单峰特性,最小涡量在涡心处,而空泡流中梢涡空泡区域的涡量随周向的分布呈现双峰特性,最小涡量不在涡心处. 相似文献
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The aim of this work is to analyze the hydroacoustic behavior of a marine propeller through the acoustic analogy and to test the versatility and effectiveness of this approach in dealing with the many (and relatively unexplored) issues concerning the underwater noise and its numerical prediction. In particular, a propeller in a noncavitating open water condition is examined here by coupling a Reynolds averaged Navier–Stokes hydrodynamic solver to a hydroacoustic code implementing different resolution forms of the Ffowcs Williams–Hawkings (FWH) equation. The numerical results suggest that unlike the analogous aeronautical problem, where the role played by the nonlinear quadrupole sources is known to be relevant just at high transonic or supersonic regime, the pressure field underwater seems to be significantly affected by the flow nonlinearities, while the contribution from the linear terms (the thickness and loading noise components) is dominant only in a spatially very limited region. Then, contrary to popular belief and regardless of the low blade rotational speed, a reliable hydroacoustic analysis of a marine propeller cannot put aside the contribution of the nonlinear noise sources represented by the turbulence and vorticity three-dimensional fields and requires the computation of the FWH quadrupole source terms. 相似文献
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文章结合一种密度大于水的新型潜器—重水潜器(Heavier-than-water AUV,简称 HTW),采用 RANS 方法和重叠网格计算了该潜器的水动力性能和绕流流场。文中计算了不同攻角和漂角情况下重水潜器的阻力、升力及俯仰力矩,对其周围流场水动力学性能进行了分析,并通过流场的流动结构研究了受力随姿态变化的规律。文中将采用重叠网格方法的计算结果与 FLUENT 计算值以及风洞试验结果进行了比较,表明重叠网格方法可较好地模拟重水潜器的自由态绕流问题。该研究为该潜器的总体设计与运动控制提供了有价值的参考。 相似文献
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《船舶与海洋工程学报》2015,(3)
To deal with the effect of compressible fluids on the supercavitating flow over the subsonic disk cavitator of a projectile, a finite volume method is formulated based on the ideal compressible potential theory. By using the continuity equation and Tait state equation as well as Riabouchinsky closure model, an "inverse problem" solution is presented for the supercavitating flow. According to the impenetrable condition on the surface of supercavity, a new iterative method for the supercavity shape is designed to deal with the effect of compressibility on the supercavity shape, pressure drag coefficient and density field. By this method, the very low cavitation number can be computed. The calculated results agree well with the experimental data and empirical formula. At the subsonic condition, the fluid compressibility will make supercavity length and radius increase. The supercavity expands, but remains spheroid. The effect on the first 1/3 part of supercavity is not obvious. The drag coefficient of projectile increases as the cavitation number or Mach number increases. With Mach number increasing, the compressibility is more and more significant. The compressibility must be considered as far as the accurate calculation of supercavitating flow is concerned. 相似文献
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To deal with the effect of compressible fluids on the supercavitating flow over the subsonic disk cavitator of a projectile, a finite volume method is formulated based on the ideal compressible potential theory. By using the continuity equation and Tait state equation as well as Riabouchinsky closure model, an “inverse problem” solution is presented for the supercavitating flow. According to the impenetrable condition on the surface of supercavity, a new iterative method for the supercavity shape is designed to deal with the effect of compressibility on the supercavity shape, pressure drag coefficient and density field. By this method, the very low cavitation number can be computed. The calculated results agree well with the experimental data and empirical formula. At the subsonic condition, the fluid compressibility will make supercavity length and radius increase. The supercavity expands, but remains spheroid. The effect on the first 1/3 part of supercavity is not obvious. The drag coefficient of projectile increases as the cavitation number or Mach number increases. With Mach number increasing, the compressibility is more and more significant. The compressibility must be considered as far as the accurate calculation of supercavitating flow is concerned. 相似文献
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水下结构声固耦合振动的特征值计算 总被引:8,自引:0,他引:8
针对水下结构声固耦合振动计算中出现的非对称矩阵(与频率相关)的特征值问题,本文基于共轭子空间迭代法,提出了计算水下结构振动固有频率和振型的双重迭代算法.数值算例表明:该算法收敛性好,用于水下结构声固耦合振动的特征值计算是有效的.文中分别将流体视为不可压缩和可压缩两种情况建立了流固耦合方程,计算了板、加筋板和方箱振动的固有频率和振型,将干模态和湿模态、不可压缩流体和可压缩流体的计算结果进行了比较,并分析了结构刚度和流体边界条件对附加水质量影响系数的影响. 相似文献