摘要:

The effect of wall friction on the sequent depths ratio in classical hydraulic jumps is analysed. Based on experimental data, an approach is presented by which it is seen that the sequent depths are not only influenced by the inflow Froude number, but also by the inflow Reynolds number, and the inflow aspect ratio. The prediction is compared to own and other experimental data, and a fair agreement between the two is found. Finally, an expression is given for the limit condition for which scale effects are still absent. All results are presented in terms of jump inflow quantities and thus ensure a simple application to design problems.

ISSN:0022-1686    

DOI:10.1080/00221688909499111

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

For a channel with a deep and a shallow region an eigenvalue-eigenfunction solution is obtained for the dispersion of effluent released in either the deep or shallow region. Each region is assumed to have a constant velocity and constant dispersion coefficient and the boundary condition at the discontinuity is the equality of mean concentration and concentration flux.

ISSN:0022-1686    

DOI:10.1080/00221688909499112

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Laboratory experiments on the structure of uniform flow in a smooth open channel are reported. Velocity profiles (Figs. 2 and 3) and turbulence intensity profiles (Fig. 6) as well as friction velocity (Table 2) were measured. It was found that:

ISSN:0022-1686    

DOI:10.1080/00221688909499113

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

One method for obtaining solutions for single- and multi-layer flow over bottom humps and through sidewall contractions is to consider the variation in mechanical energy with layer thickness at key cross-sections. However, previous models of gradually-varying multi-layer flow have been restricted to flows which remain subcritical with respect to all but the slowest internal wave speed. This paper shows how the energy extrema method can be used over the full range of flow conditions; from subcritical with respect to all internal wave speeds to supercritical with respect to the free surface wave.

ISSN:0022-1686    

DOI:10.1080/00221688909499114

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The dynamic pressures around a large diameter vertical cylinder resting on the flume bed and piercing the free surface are measured under regular wave conditions and compared with the results of MacCamy and Fuchs' linear diffraction theory. The linear diffraction theory has been modified to account for the nonlinear effects. The results mostly pertain to deep water conditions with drag effects being negligible and are presented in nondimensional form. The agreement between the theory and experiments are in general found to be good.

ISSN:0022-1686    

DOI:10.1080/00221688909499115

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Unsteady waves generated in a wave channel of finite length are studied in this paper. Linear wave theory is used to formulate the problem. The Laplace transform is applied to the time and the finite Fourier cosine transform to the space coordinate to solve the corresponding initial boundary value problem. Exact analytic solutions for generations of surface waves and hydrodynamic forces on the wavemaker are presented. Examples of flap wavemaker problem are used to demonstrate present theoretical solutions. The present theory can also be used to simulate wave generations in a channel of infinite length by specifying a relatively large channel length. Comparisons of present results to those obtained by using finite element method and by analytic integral method show favorable agreement.

ISSN:0022-1686    

DOI:10.1080/00221688909499116

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A numerical model is presented for simulating the flow and the settling performance of primary clarifiers. The model consists of 2 parts: a flow model providing the velocity and turbulent viscosity/diffusivity field and a suspended-sediment transport model for determining the particle concentration field. The model is an improvement over simple algebraic relations and previous numerical models because, with the aid of the k-e turbulence model employed, it allows a more realistic prediction of the velocity and turbulent diffusivity distribution, and also because it accounts for differential settling by solving concentration equations for individual fractions of different particle sizes. The model is applied to calculate the flow field, the flow through curve and the suspended solids concentration field in the primary settling tank of the City of Sarnia, Ontario, Canada for various overflow rates and settling velocity curves. In spite of the geometric simplifications employed in the model the concentration profiles and removal efficiencies are in very good agreement with measurements, while the agreement about the flow field and the flow-through-curve is more qualitative. The calculations were carried out both on a personal and a Siemens 7881 main frame computer, and the ratio of computing times was found to be 1:150.

ISSN:0022-1686    

DOI:10.1080/00221688909499117

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The paper describes an analytical and experimental investigation of the circulation and mixing induced by a buoyant surface jet discharging into an originally stratified reservoir. Several methods were used to study the circulation patterns and the degree of mixing in the model. Systematic experiments were conducted to study the effects of jet-discharge and reservoir-density. Experiments were also conducted to study interfacial shear stresses and the degree of entrainment. Good agreement was obtained between theory and experiment.

ISSN:0022-1686    

DOI:10.1080/00221688909499118

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Literature reviews on (1) process of water drop impact on dry or wet surfaces and (2) splash soil loss due to water drop impact are presented. It appears that water drop impact generates large instantaneous pressure of a magnitude comparable to that of water hammer pressure. However, this pressure only lasted for a very short time and decays within milliseconds. Published studies on soil loss due to water splashing on soil surface shows that splash soil loss is largest when the soil is covered by a thin film of water. This feature is made use of to develop a soil detachment model based on eroding pressure. The various parameters needed in the model are derived from published data. The developed model appears to produce encouraging results.

ISSN:0022-1686    

DOI:10.1080/00221688909499119

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Measurements of the rate of alongshore shingle transport and the corresponding incident breaking wave climate have been carried out at a beach site in Sussex, U.K. Shingle movement has been sampled by means of a tracer and by shingle traps. A transport formula is presented and the calibration techniques described.

ISSN:0022-1686    

DOI:10.1080/00221688909499120

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor