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101.
本文基于雷诺平均N-S方程,并结合RNG k-e方程建立了粘性数值波浪水槽,对不同波陡、不同相对水深、不同相对波高的非线性规则波的阻尼消波问题和波场分布进行研究。文中提出了两种描述消波区内部阻尼变化的阻尼函数,分别适用于小波陡情形和高波陡情形。研究结果表明,小波陡组消波区可设为一个波长,阻尼系数取10~4~10~5即可满足消波要求,计算结果与实验结果及造波理论吻合良好;高波陡组消波区可设为两个波长,阻尼系数取10~4~10~5亦可满足消波要求,计算结果与实验结果吻合良好。此外,当波陡较小时,波场内反射情况的小幅改变即可对整个波场造成影响,特别是当水深较浅时这种影响极为明显,需谨慎考虑。当波陡较大时,水波能量较高,整个波场沿水波传播方向可观测到明显的衰减现象,在具体试验中需进行考虑。 相似文献
102.
通过象山港水域的潮波运动数值模拟,分析了象山港M4分潮的生成和增长机制.结果说明,潮波传播中的非线性底摩擦效应是M4分潮生成和增长的主要控制因子,M4分潮在湾内的共振现象也起着重要的放大作用二平流效应在绝大部分区域中抑制了M4分潮的发展,只有在佛渡水道中一些岛屿周围极小区域内对M4分潮有增强作用.潮滩在湾内对M4分潮的影响极其微弱. 相似文献
103.
smail Hakk
zler 《Ocean Engineering》2008,35(1):17-27
The beach profile and sediment transport are very important factors in the design of coastal structures, and the beach profile is mainly affected by a number of parameters, such as wave height and period, beach slope, and the material properties of the bed. In this study, considering wave height (H0=6.5, 11.5, 16, 20, 23, 26 and 30 cm), wave period (T=1.46 and 2.03 s), beach slope (m=1/10 and 1/15) and mean sediment diameter (d50=0.18, 0.26, 0.33 and 0.40 mm), an experimental investigation of coastal erosion profile (storm profile) was carried out in a wave flume using regular waves, and geometric characteristics of erosion profile were determined by the resultant erosion profile. Dimensional and non-dimensional equations were obtained by using linear and non-linear regression methods through the experimental data and were compared with previously developed equations in the literature. The results have shown that the experimental data fitted well to the proposed equations with respect to the previously developed equations. 相似文献
104.
The Zoige Basin is located in the eastern margin of the Qinghai-Xizang Plateau, in which two cores, RH and RM, have been drilled,
with the depths of 120 m and 310 m respectively. The former with the bottom age of 826 kaB. P. has been divided into 21 stages
according to the multi-proxy analysis, which could be basically compared with the oxygen isotope record of deep-sea core.
The palaeoclimatic and palaeoenvironmental process of the Zoigê Basin over the past 900 kaB. P. is reconstructed, and the
comparison of core RH with the Luochuan Loess record is made. 相似文献
105.
106.
Wolfram Neutsch Herbert Kalisch Horst Fichtner S. Ranga Sreenivasan Maurice Shevalier 《Astrophysics and Space Science》2003,288(3):391-408
The study of the expansion of the solar wind out of a system of coronal holes is continued. To this end, we consider the numerical
integration of partial differential equations for problems with icosahedral symmetry, in general. First, employing Weyl theory,
orbifold coordinates are introduced. Second, the icosahedral coordinates are discussed in detail. Third, following an analysis
of the properties of these coordinates and the derivation of a few expressions useful for grid construction, various alternatives
for the distribution of lattice points required for numerical integration are considered. A comparison of these numerical
grids motivates the choice of a specific grid optimized for the numerical integration carried out in the accompanying paper
by Kalish et al.(2002).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
107.
Mirko Siegert Marcel Gurris Claudia Finger Erik H. Saenger 《Geophysical Prospecting》2022,70(1):152-172
In this paper, the methods of digital rock physics are applied to determine pressure-dependent effective thermal conductivity in rock samples. Simulations are performed with an in-house three-dimensional finite volume code. In the first step, four numerical models are derived from a given tomographic scan of Berea sandstone. Consequently, simulations of the thermal conductivity at ambient conditions are performed and validated with experimental data. In a second step, a new workflow for the determination of the pressure-dependent thermal conductivity in rock samples is elaborated, tested and calibrated. Results originating from the derived workflow show very good agreement with experimental data. 相似文献
108.
109.
It has been well studied that the γ-function explicit method can be effective in providing favorable numerical dissipation for linear elastic systems. However, its performance for nonlinear systems is unclear due to a lack of analytical evaluation techniques. Thus, a novel technique is proposed herein to evaluate its efficiency for application to nonlinear systems by introducing two parameters to describe the stiffness change. As a result, the numerical properties and error propagation characteristics of the γ-function explicit method for the pseudodynamic testing of a nonlinear system are analytically assessed. It is found that the upper stability limit decreases as the step degree of nonlinearity increases; and it increases as the current degree of nonlinearity increases. It is also shown that this integration method provides favorable numerical dissipation not only for linear elastic systems but also for nonlinear systems. Furthermore, error propagation analysis reveals that the numerical dissipation can effectively suppress the severe error propagation of high frequency modes while the low frequency responses are almost unaffected for both linear elastic and nonlinear systems. 相似文献
110.
复杂矿区三维地质可视化及数值模型构建 总被引:1,自引:3,他引:1
复杂三维地质可视化和数值模型的构建是采矿、岩土及水利水电工程中常常遇到的关键问题。针对数值模拟软件在复杂矿区地质体模型构建及单元网格划分等前处理问题上存在的不直观、工作量大等缺点,结合矿业软件在复杂三维地质体建模的强大优势,在研究线框模型和块体模型差异的基础上,提出了基于线框模型的复杂矿区三维地质可视化及数值模型构建技术。根据线框模型特点不同,以地表和采空区模型为型,分别阐述了基于Surpac的表面模型和实体模型无缝转换成MIDAS/GTS数值模型的有效方法,并将该技术成功应用于冬瓜山铜矿复杂采空区群围岩稳定性研究中。结果表明,该方法是可行、有效的,从而为矿山开采设计、安全分析及复杂地质体结构的岩土工程数值模拟分析提供了一种新的建模方法。 相似文献