ISSN:0022-1686    

DOI:10.1080/00221689609498760

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The interaction between waves and a fluid-mud layer is studied theoretically and experimentally in the present paper. In addition the effects of a net current, or a net current together with waves are investigated. Experiments were carried out in a wave-current flume using two artificial muds. It was found that turbulence intensities in the water layer decreased when a layer of fluid mud was present. The observed wave decay and the wave-induced velocities in the liquefied bed agreed well with those calculated using a modified version of a model due to Gade (1958). The experiments also showed that observations or measurements made at a sidewall should be interpreted with care.

ISSN:0022-1686    

DOI:10.1080/00221689609498761

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper presents the results of a laboratory study on the erosion of sand beds by submerged circular impinging vertical turbulent jets of water for the erosion parameterEcless than 5. The variation of the maximum scour depth with impinging distance was studied and this revealed two major flow regimes referred to as the Strongly Deflected and the Weakly Deflected Jet Regimes. The conditions under which they exist were established. The asymptotic eroded bed profiles were found to be similar except at very low values of the erosion parameter when made non-dimensional using the maximum scour depth as the length scale. Another length scale was introduced to achieve similarity for all values of the erosion parameter. Using results from this study and the literature, semi-empirical equations have been developed for the characteristic lengths of the erosion profiles in the asymptotic state. Equations that may be used for different values of the relative density difference δρ/ρ are proposed for the maximum scour depth and the scour hole radius using data from this study and from the literature which includes data on air jets impinging on loose beds of sand and polystyrene.

ISSN:0022-1686    

DOI:10.1080/00221689609498762

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

As a river bed of heterogeneous gravel degrades, previously buried material becomes exposed on the surface and thus available for transport. As the river aggrades, surface material and bedload becomes buried, resulting in a transfer of material to the substrate. Any predictive treatment of bed variation in gravel-bed rivers must account for this process in terms of an appropriate transfer, or exchange function at the interface between the surface layer and substrate. In the case of degradation it has long been recognized that substrate is incorporated directly into the surface layer. In the case of aggradation, however, existing formulations are based on little more than educated speculation. Here data from a large-scale experiment on the aggradation and selective deposition of gravel are used to back-calculate a form for the transfer function. The empirical relation so derived suggests that material transferred to the substrate can be represented as a weighted average of bedload and surface material, with a bias toward bedload.

ISSN:0022-1686    

DOI:10.1080/00221689609498763

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Wind/wave interactions in the surf zone were studied using a wave tank and environmental wind tunnel. Waves were modelled at approximately 1/50 scale and broke on a model scale beach of 1/20 slope. The wind was simulated using accelerated growth techniques over a relatively short fetch, and a model scale of roughly 1/100 was achieved. Thus there was some scaling mis-match between wind and wave simulations.

ISSN:0022-1686    

DOI:10.1080/00221689609498764

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A second order Godunov-type nonoscillatory scheme is presented for solving the steady shallow water equations in generalized Lagrangian formulation and applied to compute steady supercritical flows. The Lagrangian distance and a stream function are used as the independent variables which have intrinsic flow adaptive property embedded. Numerical examples involving oblique hydraulic jumps, tangential discontinuities and negative waves and their interactions are given. It is illustrated that all the flow discontinuities in steady supercritical flows can be accurately and efficiently computed by using the generalized Lagrangian method in junction with the present high resolution scheme.

ISSN:0022-1686    

DOI:10.1080/00221689609498765

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The accelerating movement to restore wetlands, and especially to return flood plains to more natural conditions, leads to the widespread introduction and propagation of reeds and other forms of more-or-less flexible vegetation. These reeds and other types of vegetation then influence flows across wetlands, and the need to control flooding sequences and intensities using numerical models and other hydroinformatics tools necessitates a better understanding of this influence of flexible vegetation on flows. A numerical model is introduced that serves as a means for investigating the influence of the several factors that contribute to flow resistance induced by flexible vegetation. The model has been partially calibrated from data obtained in experiments with inflexible vegetation.

ISSN:0022-1686    

DOI:10.1080/00221689609498766

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A steady state, length scale model and a three-dimensional stratified hydrodynamic/pollutant transport model were used to determine the pollutant distribution in a nearshore area of Lake Ontario, Canada, due to loading from Mimico Creek. The steady state model, named CORMIX3, is a knowledge based expert system intended for surface discharges subject to constant current flowing in one direction. The 3D time-dependent hydrodynamic/ pollutant transport model can simulate wind-induced circulation in the bay under both isothermal and stratified conditions. Field data taken around the mouth of Mimico Creek were compared to the models' dilutions for cases under isothermal and stratified conditions. CORMIX3 predictions agreed quite well with the 3D model's predictions as well as the field data.

ISSN:0022-1686    

DOI:10.1080/00221689609498767

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

LENGTH AND DEPTH OF HYDRAULIC JUMP IN SLOPING CHANNELSD. Husain, A.A. Alhamid and Abdel-Azim M. Negm, Journal of Hydraulic Research, Vol. 32, 1994, No. 6, pp. 899-910

ISSN:0022-1686    

DOI:10.1080/00221689609498768

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0022-1686    

DOI:10.1080/00221689609498769

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor