Abstract: This paper discribes the study of preferential flow in soil.A simple method is introduced to the quantitative fractions of the saturated conductivity for soil macro-,meso-and micro-pores.The variations of saturated conductivity of preferential and Darcy flow are also discussed.
Abstract: Alaboratory measurement of capillary pressure-saturation curves for granite sample got at construction site of the Three Gorges Project is introduced in this paper.The method of immiscible displacement is adopted in the experiment.The data measured show that some analogies exit between the capillary pressuresaturation curves for unsteady flow in fracture and in parous media,that is hysteresis phenomena in the capillary pressuresaturation ralationship,drainage curve of wetting phase show bubbling pressure,and irreducible water saturation; residual saturation for imbibition curve.The analogies show feasible that the research achievements and mathematical models of characteristics of unsteady flow in porous media can be used in studies of unsteady flow in fractures.
Abstract: Based on Horton law,this paper proposes the property of tip set of branching networks which is more significant in actual works,and the self-similar dimension of tip set is obtained.Then multifractal nature of tip set of branching networks with two different branching lenghth ratios is described,and its f(α)～α spectrum as well as Dq～q spectrum are analysised qualitatively.Finally,their significance in the real river networks are discussed.
Abstract: Based on the time series analysis and the optimization control theory,this paper propses the water level forecasting model with backwater effect,which basically overcomes the shortages of not directly dealing with backwater effect in hydrologic way and complicated calculation in hydraulics way.For prismatic cannel the constraint condition of paramenters of the model is geven.The water level forecasting of the Jinjiang Reach of the Yangtze River with backwater effect is well solved by the model.
Abstract: In this paper,the hydr ologic characteristics of semi-desert basin was analyzed,two different water balance equations respectively for desert covered area and non desert-covered area in semi-desert basin were developed,and hence a calculation method for desert-covered area was proposed.The method was tested with field surveyed results of nine semi-desert basins.The calculated and surveyed desert-covered area were very closed.
Abstract: The (LP-DP) Linear programming-Dynamic Programming Proposed by Becker & Yeh first in 1974 is a powerfull model.But,it is not applicable to parallel system and not strict in terms of theory.The LP-DPmodel proposed in this paper is more useful and strict in terms of theory.It can be applied in all systems including parallel condition and has been successfully applicated in the real-time optimal operation in Jiang-Xi province hydrothermal power system.
Abstract: Extreme sea statistics and combinations of environmental events or response for structures are very important problem in performance evaluation and design of coastal and offshore structures.A probabilistic method is developed that leads to the combination of typho on (hurricane) or winter storm induces winds,waves,currents and surge for a generic site.The traditional recommendation for the fixed structures is a combination of the 100 years maximum wave height with the 100 years wind and current.This approach is,however,unduly conservative,since the largest wind,wave and current values in 100 years are not expected to occur at precisely the same time.Previous studies of combinations of extreme sea environmental conditions fall into two categories:first,the generic load model defines a surface in the multivariate space of meteoro logicaloceanic variables,such as the joint probability of waves,currents,winds and storm surges; second,use of the structural response to combine the environmental variables,such as overturning moment (OTM),base shear forces and etc.While the great majority of publications are concentrated in combinations of responses,although 100 years response is not corresponding to wave,wind and current with 100 years joint probability.Since the combination design criteria is considered with extreme statistics of individual environmental events and their joint probability,in t his paper some new concept for mentioned above problems is proposed.
Abstract: The govern equations of 2-D unsteady mobile-bed turbulent model in the orthogonal curvillinear coordinates,i.e.,the water movement equation and the non-equilibrium suspended load transportequation in tidal stream,were given in this paper.Techniques are suggested for some questions in calculations,such as,the basic data,typical tide level process,routhness,the suspended load size and the setting velo city,sediment recovery coefficient in non-equilibrium suspended load equation,and the criterion of erosion and deposition.The tide level and velocity process,the recir culate zone near the groin and the bed deformation during the regulating engineering were calclated by the example of Yongjiang at the tidal funnel about 5 kilometer from Zhenghai bend to Dayushan.The results are agreeable the observed data.The changes of stream structure and erosion and deposition on the channel at the Zhenghai port due to the Lenbo Bridge were calculated by the equations.
Abstract: This paper presents the experiment phenomena of particle at bottom in cylinder circulation flow.When the bed load round the cylinder with water flow,a region of non-sediment's moving will be formed in the bed layer near the cylinder.Based on the law of kinetic energy,the formula in the region of non-sediment movement is set up.The influence of the particle size,the diameter of cylinder and the Froude coefficient to the region there are no particle's movement are analysed.The analysis result from the formula agreeds with the experiment phenomena.
Abstract: The selection about culvert shape behind valve is one of the key problems in hydraulic design for Three Gorges ship lock.Comparisons of hydraulic natures such as flow pattern,pressure fluctuation,cavitation,and vibration between two kinds of culvert shape behind valve,top expansion and bottom sudden expansion,are carried out in this paper.Due to the obvious difference,bottom sudden expansion culvert is used in Three Gorges ship lock,which can fulfill the operating conditions of filling valve.
Abstract: Based on the Modern Algebra theory,this paper,according with the reality of Chinese lakes,preliminarily sets up a classified system of Chinese lakes,dividing the Chinese lakes into two classes,four subclasses and eight types.
Abstract: This paper is a continuation of "On scenic water resources",further deals with some related concepts and connetions of scenic water resources,and makes the classification of scenic water resources in accordance with six criterions.Scenic water resources can be classified into three groups in accordance with its genesis,nine groups in accordance with its existing space,five groups in veiw of the aesthetics features,seven groups based on scenic effects,four groups in terms of utilization function,four groups rested on viewing positions and three groups according to suitable veiwing times.This paper also deals with the third classification in particular-the group of scenic effects,for this kind of classification can fully embody the features of scenic water resources.
Abstract: The reconstruction of chaoticstate space and the diagnosis of chaotic behavio ras well as the nonlinear state space prediction methods of observed hydrologic time series are discussed.The advances of chaotic analysis in hydrology are also reported.The works to be carried out are considered in the future.
Abstract: In this paper,ten hydrological watershed models' structures and their simulating technologies used in the first hydrological forecasting technology competition of China have been clearly classified and summarized from each key link,and the simulation and application of the models mentioned above have been analyzed and summarized in accordance with the phenomenon revealed by the verification results in this competition.