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This paper discusses the numerical prediction of the induced pressure and lift of the planing surfaces in a steady motion based on the potential flow solver as well as the spray drag by use of the practical method.The numerical method for computation of the induced pressure and lift is potential-based boundary element method.Special technique is identified to present upwash geometry and to determine the spray drag.Numerical results of a planing flat plate and planing craft model 4666 are presented.It is shown that the method is robust and efficient and the results agree well with the experimental measurements with various Froude humors. 相似文献
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将地质灾害治理工程项目管理及质量控制分为4个阶段：策划(可行性研究)阶段,准备阶段,施工阶段．验收审查阶段,分别阐述其管理及质量控制的重点内容。 相似文献
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Stability of the marine vessels in different conditions is one of the most important problems in the design of a planing vessel. In this research, the effects of some important design parameters (mass, longitudinal center of mass, deadrise angle, and length) of DTMB 62 model 4667-1 planing hull on the drag and also on the longitudinal dynamic stability (porpoising) are investigated in the velocity range of 2.12–8.486 m/s in calm water. In this paper, both numerical simulation of Reynolds Average Naiver Stokes (RANS) equations and semi-empirical formulas of Savitsky are used to analyze the motion of a 4667 planing vessel in calm water with two degrees of freedom (2DOF). For this purpose a finite volume, ANSYS-FLUENT, code is used to solve the Navier-Stokes equations for the simulation of the flow field around the vessel. In addition, an explicit VOF scheme and SST- Kω model is used with dynamic mesh scheme to capture the interface of a two-phase flow and to model the turbulence respectively, in 2DOF model (heave and pitch). Also, the results of both methods are compared with each other. According to the present results, changing the aspect ratio of the vessel and also the longitudinal center of gravity have the most effect on the porpoising region. 相似文献
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关于山东省海滨旅游区旅游开发之思考 总被引：2，自引：0，他引：2
山东省海滨旅游区由于长期未有实现在宏观调控下的全区域整体规划和开发,导致旅游资源优势迟迟不能转化为经济优势,加之各地市目标市场的单一性和趋同性,不驻引发了内部竞争,而且在亚洲金融危机冲击下明显暴露了旅游产业的脆弱性。为此作者在分析该区发展旅游业的五大优势条件和不利因素基础上,提出了发展旅游业的基本构想。 相似文献
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Current paper presents a mathematical model based on 2D-asymmetric wedge water entry to model heave and pitch motions of planing hulls at non-zero heel angles. Vertical and horizontal forces as well as heeling moment due to asymmetric water entry are computed using momentum theory in conjunction with added mass of impact velocity in vertical and horizontal directions. The proposed model is able to compute sway and yaw forces, roll moment, as well as heave and pitch motions in calm water and regular waves. Validity of the proposed model is verified by comparing the results against existing experimental data in both symmetric and asymmetric conditions. Ultimately, different parametric studies are conducted to examine the effects of non-zero heel angle on dynamic vertical motions. The resulting sway and yaw forces due to asymmetric motion are also derived and effects of heel angle on these side forces are investigated. 相似文献
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李相然 《地球科学与环境学报》1997,(Z1)
任何城市都是建立在特定的地质体上，城市的建设与发展都要以这个特定的地质体为基础。城市工程地质环境与城市规划之间存在着密切的联系。本文分析了烟台市的工程地质环境，探讨了城市工程地质环境与城市规划用地条件评价和城市规划建设的合理布局之间的关系。 相似文献
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高速滑行艇处于滑行状态时的阻力性能一直是滑行艇水动力性能研究的重点和难点。首先采用半经验半理论的Savitsky法对棱柱形滑行艇的航行姿态与阻力进行研究分析,计算纵倾结果与试验结果吻合良好。然后改变滑行艇的长宽比、重心纵向位置与底部斜升角参数,进一步研究三种参数变化对滑行艇航行姿态与阻力性能的影响。研究结果表明:基于半经验半理论的Savitsky方法可用于棱柱形滑行艇的阻力性能分析;在高速阶段,长宽比、重心纵向位置与底部斜升角参数对阻力影响较大。 相似文献
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Mohammad Saeed SEIF Ebrahim JAHANBAKHSH Roozbeh PANAHI Mohammad Hossein KARIMI 《中国海洋工程》2009,23(3):517-528
High speed planing hulls have complex hydrodynamic behaviors. The trim angle and drafts are very sensitive to speed and location of the center of gravity. Therefore, motion simulation for such vessels needs a strong coupling between rigid body motions and hydrodynamic analysis. In addition, free surface should be predicted with good accuracy for each time step. In this paper, velocity and pressure fields are coupled by use of the fractional step method. On the basis of integration of the two-phase viscous f... 相似文献
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近年来高等级公路正在我国迅速发展,养护与维修路面是一项迫切任务。以2000 DC型铣刨机为例介绍其在维修路面中的作用,以及这种铣刨机的结构、技术参数、主要性能及现场应用注意事项。 相似文献