• 全国中文核心期刊
  • 中国科技核心期刊
  • 美国工程索引(EI)收录期刊

1991 Vol. 2, No. 1

Display Method:
Research and Applications of a Forecasting Model of Typhoon Surges in China Seas
Wang Xinian, Yin Qingjiang, Zhang Baoming
1991, 2(1): 1-10.
Abstract:
A dynamic-numerical, typhoon surge model has been developed by the authors. The model is two-dimensional in space. The equations of fluid motion are solved numerically with finite-difference shills, incorporating finite-amplitude effects and the variation of Coriolis parameter with latitude, but dropping the advective terms. The method of non-dimensional analysis For widely used formulae of pressure distribution in a typhoon area was employed to choose the best representative ones of them.The model has been used in real-time forecasting of typhoon surges since 1988. Satisfactory results were obtained in the real-time predictions during more than two years when the typhoon tracks and their intensities were forecasted accurately.
Three High-performance Difference Schemes for One- dimensional Unsteady Open Channel Flow Computations
Hu Siyi, Tan Weiyan
1991, 2(1): 11-21.
Abstract:
This paper first summarizes four physically-posed requirements on the difference scheme used, i. e., conservation, upwindn}ss, positivity (or monotonicity-preserving), and high-resolution in discontinuities. In the recent over one decade, a lot of schemes satisfying these requirements have been proposed and widely used in gas dynamics. Among them, three types of schemes, including the flux-vector splitting (FVS), flux-difference splitting (FDS), and flux-corrected transport (FCT), are transferred to the computations for one-dimensional unsteady open channel flows, and related formulas are derived based on the concrete form of the Saint-Venant system of equations in consideration of the geometric irregulKrity of natural rivers. Finally, these methods are verified through a dam-break case study, yelding results that are close to each other, so that brilliant prospects of their applications can be foreseen.
Effects of Aspect Ratio and Sidewall Roughness on VeSocity Distribution and Resistance Coefficient in Rectangular Open Channels
Hui Yujia, Hu Ghunhong
1991, 2(1): 22-31.
Abstract:
A series of experiments were conducted in a rectangular flume by varying aspect ratio and sidewall roughness. The vertical velocity distributions over cross sections are analysed systematically. It is demonstrated that each velocity profile can be divided into a logarithmic velocity region in the lower part and a parabolic vciocity region in the upper part, according to its characteristics. The expressions of velocity distribution and the dividing line between the tworegions, as well as the variations of the location of maximum velocity, with respect to aspect ratio and sidewall roughness, are given herein. Moreover, the variation of resistance coefficients for smooth and rough open-channel flows, the separation of bed and sidewall resistance coefficients, and the distributions of bed and sidewall shear stresses, are also discussed.
Dynamic Interface between Fresh Water and Salt Water
Lu Xianbi
1991, 2(1): 32-41.
Abstract:
Under certain conditions, the effect of hydrodynamic dispersion is relatively weak, so that an abrupt interface approximation can be used in studying seawater intrusion in coastal aquifers. In this paper the boundary element method and a Hcle-Shaw model are used for numerical simulation. The influence factors on the interface movement are analyzed. A main feature of the nonstationary interface, slowly inlandward advance and rapidly seaward return, is introduced and can be applied to groundwater resources management and protection.
Some Factors of Impacts on Snowfall Over Qinghai-Xizang Plateau
Zou Jinshang, Cao Caizhu
1991, 2(1): 42-49.
Abstract:
The characteristics of the geographical distribution of snowfall and depth of snow-cover are summarized, based on the meteorological data of 1966-1975 for various regions of the Qinghai-Xizang plateau. The relationships between the transition of winter-summer circulation and the snowfall over the plateau are investigated in detail. Some factors of impacts on snowfall over the plateau are also analysed and discussed. These factors are atmospheric circulation, and synoptic-scale low pressure systems companying with upward motion, altitude, orography including river valleys, and so on.
Relationship Between Monthly 500hPa Height fields and Precipitation Fields Over China in Summer
Huang
1991, 2(1): 50-57.
Abstract:
Correlation and regression analyses based on the data of the period 1951-1985 are employed for investigating the relationship between monthly 500hPa height fields and precipitation fields over China in summer. The results show that there is a significaat relationship between the two fields. An intense correlation area occurs in the eastern part of China, and another one is in the western part which is about 180 degrees longitude from the former. An area with an intense regression factor, which is diagnosed by the method proposed in this paper, is in the same location with the intense correlation area, but it is smaller. In China, the area where predictability is intensely represented varies with monthly. It is in the Yellow River basin in Junc, and in the Yangtze River basin in July and August. The relationship between the two fields in terms of either correlation or regression implies higher stability.
A Review of Some Aspects about Flow Concentration Computations
Wen Kang, Li Qi
1991, 2(1): 58-65.
Abstract:
Water Quality Planning and Its Evolution
Du Yuguo, Ye Changming
1991, 2(1): 66-71.
Abstract:
1991, 2(1): 72-72.
Abstract: