摘要:

The effect of benthic organisms (Oligochaeta and Chironomidae) on the erosion of cohesive sediments was studied in a laboratory flume. The critical erosive velocities were shown to be 2-3 times smaller than that of the control sediments. The effect depends strongly on the population density of benthos and temperature of sediments. It was also shown that micro-organisms (bacteria and protozoa), attached to small particles have a great impact on the transportation of suspended sediments due to the decrease in the settling velocity and the critical tractive force.

ISSN:0022-1686    

DOI:10.1080/00221689109499000

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The problem of time distortion and its effect on the similarity between sediment scale models and their prototypes is studied both theoretically and experimentally. The average velocity in the lower section of a time-distorted model often deviates from the scaled up prototype value, when unsteady flow processes are simulated. Observed dissimilar erosion or sedimentation rates can be attributed to this time distortion.

ISSN:0022-1686    

DOI:10.1080/00221689109499001

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This paper describes the design and operation of a traverse gear for the automatic measurement of boundary shear stress and velocity distributions in a fully developed turbulent flow. The purpose of the equipment was to investigate the mean flow structure in a duct of compound cross-section, and the data collected will be used in the development of mathematical models for application in river hydraulics.

ISSN:0022-1686    

DOI:10.1080/00221689109499002

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

In order to establish a fundamental theory for pipe flow of solid-liquid mixtures, this paper analyzes the pipe flow of Bingham fluids from a different viewpoint of the equation of Buckingham-Reiner. An extended Reynolds number is introduced, so that the well-known Moody diagram can be used for non-Newtonian fluids without any modification. Experiments were carried out using mixtures of water and bentonite. As a result, laws of frictional resistance in pipelines are found to hold by replacing the ordinary Reynolds number with the extended Reynolds number. A dimensionless coefficient included in the extended Reynolds number is determined which has values in the range from 1/8 to 1/6 in laminar flow. Also, it is found that the coefficient of head loss due to sudden enlargement becomes about 11 times larger than the value of water and the coefficient of head loss due to bend becomes about 8 times larger as the Reynolds number decreases.

ISSN:0022-1686    

DOI:10.1080/00221689109499003

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A high-speed photographic study was made of the hydraulic jump. It was found that the surface roller was made up of several vortices. These vortices are generated in the early part of the jump and travel downstream. As they move downstream, they grow by pairing. At the same time, water spills down the steepened surface to replenish the toe and subsequently is rolled up into new vortices. A Fourier analysis of the time series of the toe position indicates a cyclic mechanism, the frequencies of which appear to scale with the upstream velocity and downstream depth.

ISSN:0022-1686    

DOI:10.1080/00221689109499004

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A numerical scheme is presented tor the solution of the shallow water equations in a single radial coordinate. This can prove useful when testing codes for the two-dimensional shallow water equations. The scheme is applied with success to problems involving converging and diverging bores.

ISSN:0022-1686    

DOI:10.1080/00221689109499005

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The Grubert two-dimensional hydrodynamic model was modified to simulate tidal elevations and tideinduced velocities. A stability analysis of the Grubert computational scheme showed that the scheme is “stronger” in one direction. The above scheme was modified and the stability analysis shows that the modified scheme is unconditionally stable in both directions for one dimensional flow situations. Application of the modified scheme to the Singapore Strait yielded satisfactory results.

ISSN:0022-1686    

DOI:10.1080/00221689109499006

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Flow Resistance In Compound ChannelsW. R. C. Myers and E. K. Brennan, Vol. 28, No. 2, 1990, pp. 141-155

ISSN:0022-1686    

DOI:10.1080/00221689109499008

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0022-1686    

DOI:10.1080/00221689109499009

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Hydraulics Of Pipelines (Pumps, Values, Cavitation, Transients)J. Paul Tullis, John Wiley & Sons, New York 1989, pp. 262.

ISSN:0022-1686    

DOI:10.1080/00221689109499010

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor