共查询到20条相似文献，搜索用时 152 毫秒
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根据Level-Set方法和VOF方法的优缺点,近年来兴起了一类界面追踪的耦合方法——CLSVOF(Coupled Level-Set and Volume-of-Fluid Method)方法。本文阐述了该方法的耦合实现过程,通过旋转流场和剪切流场2个算例验证了CLSVOF方法相比Level-Set方法实现了计算过程中的物理量守恒,克服了VOF方法难以准确计算界面的法向和曲率的缺点。使用该方法对溃坝模型进行计算,并将数值模拟结果进行对比分析。结果表明:CLSVOF方法计算结果更加接近于实验结果,该方法相比其他界面追踪方法具有更高的运动界面追踪分辨率。由此说明CLSVOF方法模拟具有自由表面流动工程实际问题的精确性和可行性。 相似文献
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风暴潮预报方法分为两大类：其一，经验预报方法；其二，数值方法。后者包括诺模图方法和数值模式预报方法。这一讲将概要介绍建立经验预报方法的思路和较详细地叙述数值方法中的诺模图方法。所介绍的方法迄今为止仍有应用价值。１ 风暴潮的经验预报方法 风暴潮的这类预报方法包括预报员的主观经验和经验统计预报方法。前者取决于预报人员经验积累的多寡和对风暴潮复杂物理本质理解的深浅。正如伟人毛泽东所说：感觉到的东西不能深刻地理解它，理解的东西才能深刻地感觉它。经验统计预报方法的灵魂是选取物理意义清楚的气象因子（数值模式计… 相似文献
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第九讲 海浪预报技术及预报方法(2) 半理论半经验海浪预报方法 半理论半经验海浪预报方法常用的有三种:一是特征波预报方法也称有效波预报方法;二是波谱预报方法;三是能量平衡导出谱的预报方法。 相似文献
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比较了3种由Hyper-TSRB数据估算海面遥感反射比(Rn)的方法,这3种方法分别为:prosoft、优化方法和经验方法.用于比较的现场测量数据为SeaBASS数据中193个站位的水中向上辐亮度(Lu(z))及向下辐照度(Ed(z))的剖面数.比较结果显示,3种方法对于较清的水体都有很高的精度,对于混浊的水体,优化方法和经验方法都有较高的精度,其中经验方法的性能稍优于优化方法,而prosoft方法精度较差,可达50％. 相似文献
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To overcome smoothness inconsistencies in depth contours interpolated from sounding data, this paper proposes a smoothing method based on the fitting of multi-segment Bezier curves considering navigational safety. The basic principle of this method is the division of a generated depth contour into a series of bends categorized as either convex bends or concave bends. Different smoothing strategies are designed for different bends while considering the safety constraint. Convexity-preserving Bezier curves are used to fit convex bends. For concave bends, the line segment of the bend is utilized as a boundary to construct a control polygon within the interior of the bend, after which a Bezier curve is constructed based on the polygon. Experiments with real data are implemented, and the results are compared with those of other methods. The results show that the smoothing procedure for depth contours with angularities is effective and respects the safety constraint; moreover, the shape characteristics are preserved, and high positional accuracy is achieved. In addition, the proposed smoothing method is free of topological inconsistencies. 相似文献
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Extreme dynamic, non-linear response of fixed platforms using a complete long-term approach 总被引：2，自引：0，他引：2
The general theoretical basis for application of the direct long-term approach to offshore structures with non-Gaussian response is outlined. The key to the method is the determination of the short-term response distribution. Special considerations should be taken, depending on the application, and the Weibull distribution with a special fitting procedure is suggested as a short-term probability model for fixed offshore platforms. The efficiency of the method is improved by introducing smoothing functions for the variation of the Weibull parameters with the seastate.
The method is applied to a jacket and jackup platform. The results show that smoothing functions increase the efficiency considerably. The design storm method compares well with the long-term results for the selected structures, but only the long-term approach yields realistic estimates of the design extreme response when both extreme and resonant seastates contribution to the 100-year response. 相似文献
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It is suggested that the algorithm of Kalman smoothing is used to analyse and process oceanographic data. Two methods of solving the Kalman smoothing problem are given: an iteration method and a precise method. Their advantages and disadvantages are considered, as well as different cases and conclusions.Translated by Mikhail M. Trufanov. 相似文献
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The use of the Kalman smoothing technique is suggested to handle an ocean diagnosis problem. It is shown that the variety of existing diagnostic techniques may be generalized, for which purpose the smoothing problem from the theory of optimal evaluation may be used.Translated by Vladimir A. Puchkin. 相似文献
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This paper introduces a new method for the smoothing of isobathymetric lines for marine chart construction. Specific constraints have to be observed as the chart must be legible and safe for navigation. The method, based on a snake model, respects these constraints of legibility and safety which impose a direction for curve deformation. Conflicts such as self-intersections are also considered. These two points are the main contributions of the paper as current methods cannot deal with such constraints. Several case studies are presented and results obtained on real data are discussed. 相似文献
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Isobathymetric Line Simplification with Conflict Removal Based on a B-spline Snake Model 总被引：1，自引：0，他引：1
This paper introduces a new method for the smoothing of isobathymetric lines for marine chart construction. Specific constraints have to be observed as the chart must be legible and safe for navigation. The method, based on a snake model, respects these constraints of legibility and safety which impose a direction for curve deformation. Conflicts such as self-intersections are also considered. These two points are the main contributions of the paper as current methods cannot deal with such constraints. Several case studies are presented and results obtained on real data are discussed. 相似文献
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A fairing method is presented for giving a good representation of ship model resistance test data, which in general tend to exhibit a scattered trend and need to be smoothed appropriately. One component of the test data originates from the frictional resistance and can be formulated smoothly. The second component is the wave resistance which exhibits a specific harmonic character with peaks and troughs. In this method, this component is modelled using suitable harmonic cosine terms for obtaining the best representation of the corresponding resistance data. The performance of the method is then tested on two example cases, using the characteristic parameters of the sample data as input during the smoothing process. 相似文献
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