摘要:

A standard two-dimensionalk-εturbulence model is used to predict the mean flow and turbulence characteristics of submerged hydraulic jumps. An offset control volume method is developed to facilitate computation of the variable free surface. The numerical predictions are compared with experimental measurements under three conditions with supercritical Froude numbers ranging from 3.2 to 8.2 and submergence factors ranging from 0.24 to 0.85. Finally the numerical performance is evaluated and discussed in detail. It is concluded that the model is adequate for predicting the surface profile, mean velocity field and to some extent, the turbulence structure of submerged hydraulic jumps.

ISSN:0022-1686    

DOI:10.1080/00221689109498435

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This paper presents a systematic investigation on the transition from supercritical to subcritical flow at an abrupt drop. Over a wide range of experimental conditions various types of flow have been classified and the concept of low and high drops defined. When the flow on the step is supercritical, the direction of the main flow passing over the step can be decided from the momentum equation. The reason why various flow conditions are formed has been explained. The hydraulic conditions required to form various types of flow and their length characteristics have been clarified.

ISSN:0022-1686    

DOI:10.1080/00221689109498436

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A simple model is proposed for evaluating the dilution and other main characteristics of a dense boundaryattached 3-D plume, created by the disposal of heavier effluent into a quiescent homogeneous ambient. It is based on matching requirements between the near-and intermediate field, which allow the calculation of necessary quantities at the initiation of the bottom plume in terms of the initial discharge parameters. The subsequent spreading is described through a generalization of available data.

ISSN:0022-1686    

DOI:10.1080/00221689109498437

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Scouring processes of beds in cohesive and noncohesive soils are discussed. Results of many years of laboratory, field and theoretical investigations of scour processes have been generalized. Critical velocities of erosion and governing factors are considered. Analytical expressions of permissible (nonscouring) velocities are given for cohesive and noncohesive soils.

ISSN:0022-1686    

DOI:10.1080/00221689109498438

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Apart from the physical and chemical properties of the bed of a watercourse, its biological settlement can also have a major influence on bed erosion. The present paper contains a systematic review of the effects of benthic settlement on the action of flow and on sediment stability. The qualitative description centered on the physical mechanisms is supplemented by a tabulated summary of the numerical results available from the literature.

ISSN:0022-1686    

DOI:10.1080/00221689109498439

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Results of an experimental program concerning the movement of particulates in a porous medium under conditions of non-linear flow are presented. The results are compared with the limited existing data and a model developed by Sakthivadivel [8] for linear flow conditions. Modifications were required to this model to allow it to be used under the present conditions. Examination of the results suggested an alternative transport model using suitable dimensionless parameters. This model is shown to be superior to the existing model.

ISSN:0022-1686    

DOI:10.1080/00221689109498440

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Velocity and concentration profiles of solids in a rectangular channel with glass sphere movable bed for given hydraulic conditions are reported. The measurements are carried out using the phase difference optical method which allows simultaneous measurements of particle velocity and size and the calculation of time average concentration. A comparison with some theoretical formulae is reported too.

ISSN:0022-1686    

DOI:10.1080/00221689109498441

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A study of the wave runup phenomenon on smooth impermeable curvilinear slopes is conducted in order to investigate the effects of various wave parameters and slope characteristics on the runup and wave reflection. Three arbitrary models with different curvature of each circular, elliptical, hyperbolic and parabolic curves are tested with regular nonbreaking waves. An empirical equation is proposed to express the relative runup with nonlinearity. It is found that the relative runup varies with wave steepness, relative depth and relative height.

ISSN:0022-1686    

DOI:10.1080/00221689109498442

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A finite thickness porous wavemaker located in an infinite one dimensional channel is studied. Small amplitude waves are generated in the channel, while the equations derived from the simplified Biot's theory of poroelasticity are used within the porous wavemaker. Regular perturbation expansions, with a small parameterR, are applied. The flow-efficiency parameter,R, represents the easiness of water flow relative to the skeleton inside the porous wavemaker. The largerRis, the greater inertial reaction and the less viscous damping will be. ForRmuch less than 1, the increase of inertial reaction is greater than the decrease of viscous damping asRincreases. It is also found that the thickness of the porous wavemaker is a significant factor to the hydrodynamic pressure on the porous wavemaker when the thickness is small, but it is not a significant factor to wave profile.

ISSN:0022-1686    

DOI:10.1080/00221689109498443

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0022-1686    

DOI:10.1080/00221689109498434

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor