摘要:

Mobile armor layers which form during bed load transport of non-uniform sediments are shown to be closely related to the static armor layers that form by selective erosion as a result of the action of clear water flows. Two previously published numerical models of the transport of non-uniform sediments are used as a basis for the discussion. Each model is inverted, so that it predicts surface layer compositions given the imposed flow conditions and bed load transport rate and composition. Static armor is then obtained in the limit of vanishing sediment transport, under the constraint that the bedload and substrate size distributions are identical. Good agreement is obtained between measured and calculated static armor compositions over the entire grain size distribution.

ISSN:0022-1686    

DOI:10.1080/00221689009499044

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A new computational framework for one-dimensional simulation has been developed. The approach is based on use of the full de St. Venant flow equations, treatment of sediment mixtures, recognition of the distinctly different physics of suspended-load and bedload movement, use of a spatial-delay loading law for bedload, and fully coupled, implicit numerical solution of the resulting set of partial-differential equations. In eliminating most of the conceptual and numerical weaknesses of existing methods, the new approach establishes a new standard of fidelity to the governing conservation laws, whatever be the particular empirical sediment relations employed for a particular application. This article, a companion to Holly and Rahuel [2], presents some demonstrative results and a formal assessment of the method.

ISSN:0022-1686    

DOI:10.1080/00221689009499045

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The integral forms of the momentum and tracer equations were integrated on the basis of an assumption concerning a function of the spreading coefficients. The validity of this assumption has been verified with experimental results reported in the literature. The analysis led to unified analytical expressions concerning the centerline axial velocity and concentration (or excess temperature) distributions. The present findings, which rely on the same set of experiments, are being discussed and compared with previously reported results.

ISSN:0022-1686    

DOI:10.1080/00221689009499046

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

This paper presents the results of an experimental study on the characteristics of a circular turbulent wall jet growing on a rough boundary, for values of the relative roughness varying from 0.16 to 2.16. The velocity profiles in the central plane as well as the transverse velocity profiles were found to be similar. The length scales in the vertical plane were affected by the boundary roughness whereas the transverse expansion was almost unaffected. The boundary shear stress was affected considerably by the boundary roughness.

ISSN:0022-1686    

DOI:10.1080/00221689009499047

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Based on extensive experimental observations, a precise definition of the length roller in classical hydraulic jump is given. Distinction between the developed, and the non-developed roller flow is made, of which the latter was excluded for length measurements. Four series of experiments - conducted in three different channels - allowed the analysis of the length characteristics. Relations for design are proposed which involve only jump inflow quantities.

ISSN:0022-1686    

DOI:10.1080/00221689009499048

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The problem of waves passing through a gap in an infinitely long breakwater is reduced to the solution of a Fredholm integral equation of the first kind. Wave amplitudes across the gap are shown to exactly equal incident wave amplitudes, but wave amplitudes throughout the remainder of the flow must be calculated numerically. Solution accuracy is easily checked by comparing solutions for several different boundary node spacings, and it is suggested that this method appears to give results that are easier to calculate and are more accurate than previously calculated solutions.

ISSN:0022-1686    

DOI:10.1080/00221689009499049

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Stability criteria and growth rates of long-wave disturbances in gradually varying open-channel flow are derived from an amplitude evolution equation for weakly nonlinear shallow-water waves. The streamwise nonuniformity of the flow is found to influence the stability substantially, in accord with the results of Dracos and Glenne (1967). The behaviour of the instabilities is examined by extending the amplitude evolution equation with higher-order contributions.

ISSN:0022-1686    

DOI:10.1080/00221689009499050

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The kriging technique is a geostatistical estimation method developed for mining applications some thirty years ago. It can be used to interpolate the value of a given property based on the value of the same properties at various experimental points.

ISSN:0022-1686    

DOI:10.1080/00221689009499051

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

THE ROUGHNESS HEIGHT UNDER WAVES LA HAUTEUR DE RUGOSITÉ ÉQUIVALENTE DANS LE CAS DE LA HOULEA. J. Raudkivi, Vol. 26, No. 5, 1988, pp. 569-584

ISSN:0022-1686    

DOI:10.1080/00221689009499052

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

MANUAL ON OPERATIONAL METHODS FOR THE MEASUREMENTS OF SEDIMENT TRANSPORTby Ling Yuqian World Meteorological Organization Geneva. Operational Hydrological Report No. 29 (169 pp.), 1989.

ISSN:0022-1686    

DOI:10.1080/00221689009499054

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor