摘要:

A laboratory study was performed to measure the pressures caused by fluid acceleration beneath a floating parallel-piped block. Dynamic fluid pressure was measured at discrete points beneath the block for various fluid velocities, block angles of attack and block thickness-to-depth ratios. Some of these pressures tended to stabilize the block while others tended to underturn it. The measured pressures were used to calculate block underturning moments and a hydrostatic analysis was used to calculate a block righting moment. From this, a densimetric Froude underturning criteria is presented.

ISSN:0022-1686    

DOI:10.1080/00221689309498840

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A neural net was used to study the propagation of a flood wave in an open channel. The aim was to show that this kind of tool is accurate enough to be used in real time management of sewers systems. Ability of such a neural network to answer correctly was high lightened with an extensive learning base and with a reduced one.

ISSN:0022-1686    

DOI:10.1080/00221689309498841

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

HYDRAULIK DER GERINNE UND GERINNEBAUWERKEby Eduard Naudascher, 2nd edition (1992), Springer Verlag, Wien/New York ISBN 3-527-27131-7 SB DM 52,-.

ISSN:0022-1686    

DOI:10.1080/00221689309498842

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The moving hydraulic jump, considered as an example of rapidly varied unsteady flow, is theoretically revised. Experimental work is conducted to study the kinematic characteristics of the jump propagation. The position, velocity and conjugate depths of the jump during its propagation either upstream or downstream are investigated and some semi-empirical equations are derived. From this work, some differences are observed between the moving hydraulic jump propagating upstream and downstream. A phenomenon called extinction of the moving hydraulic jump is reported in the latter case. This phenomenon is explained on the grounds of previous theoretical analysis.

ISSN:0022-1686    

DOI:10.1080/00221689309498843

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The Godunov method, is adapted to computation of dambreak flood waves. Review of commonly used methods for discontinuous flows (flows with shocks) has shown the need for a new type of algorithm to cope efficiently with mixed flow regimes and strong shocks in non-prismatic channels. The one-dimensional open-channel flow equations are solved with two variants of the Godunov method: one based on linear, the other on piecewise parabolic interpolation (PPM). The proposed methods agree well with the analytical solution (where available), and perform significantly better than the other compared methods for all examined cases.

ISSN:0022-1686    

DOI:10.1080/00221689309498844

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Both numerical solutions and experimental measurements are obtained for flow within a reservoir after a partial dam breach. The dam breach is assumed to act as a flow control so that the reservoir solution can be calculated independently of the downstream flood-routing solution. Numerical solutions are obtained by using the method of characteristics to solve the St Venant equations. Boundary conditions at the breach are obtained from a weir equation, and boundary conditions at the upstream end of the reservoir are obtained by either specifying an inflow for subcritical flow, by specifying both the velocity and depth for supercritical flow or by making the level-reservoir approximation when a zero inflow occurs. A surge often, but not always, appears in the solution. Experimental measurements confirm the calculations in almost all respects.

ISSN:0022-1686    

DOI:10.1080/00221689309498845

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A numerical model is used to simulate free surface shallow water flow over bottom topographical features. The model, in which turbulence closure is achieved at the level of the turbulence energy equation, allows for the inclusion of both the hydrostatic and hydrodynamic contributions to the pressure field and, accordingly, is successful in reproducing flow separation on the downstream side of an asymmetrical sandwave structure. Experiments are described in which the geometrical and flow parameters are chosen so as to correspond to recently reported flume and field observational studies. The experimental flume studies represent a particularly detailed and well-conducted determination of mean and turbulent flow properties in highly controlled laboratory conditions. Good overall agreement is found between the model and experimental evaluations of the mean fluid velocity, the turbulence energy, the kinematical shear stress and the extent of the flow separation zone. The second application of the model involves a comparison with a recently acquired field data set based on observations made in the Taw Estuary, Devon, England. In addition to measuring the dynamical properties of the flow, a determination was also made of suspended sediment concentrations. With appropriate modification to the model, evaluations of concentration profiles are also compared with those obtained in the field observations. The overall agreement is again of an encouraging quality thus lending support to the application of the numerical model in different coastal environments.

ISSN:0022-1686    

DOI:10.1080/00221689309498846

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Development of a mathematical model of transport processes in open channel flow and the experimental verification of the model are described in this paper. The original numerical procedure for solving the unsteady 2D dispersion equation, based on an operator-splitting approach, has been developed and validated by comparison with an analytical solution. The model was used for the interpretation of dynamic measurements of tracer concentration after instantaneous injection in a laboratory channel containing a compound cross section. Two conditions were examined (the water flows in the deeper rectangular part of the channel only, and the flow over the entire width). Very good agreement between measurements and computational results was obtained.

ISSN:0022-1686    

DOI:10.1080/00221689309498847

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Landslides and avalanches plunging into lakes or reservoirs located in mountainous regions can generate large waves which can result in loss of life and significant property damage. As is the case with tsunamis generated in the ocean by underwater seismic activity, landslide induced water waves result from the motion of a solid boundary of the fluid. The present study deals with the mathematical modelling of water waves developed in a channel by a moving bed. A set of depth-averaged governing equations is derived to predict the evolution of the free surface resulting from a predetermined bed motion. These equations, which constitute a generalization of the Boussinesq system for waves over a flat bed, include both nonlinear and dispersive effects. Numerical solutions are obtained by using the finite difference method coupled with a Flux Corrected Transport (FCT) algorithm. The resulting model is used to predict the waves resulting from simple bed motions.

ISSN:0022-1686    

DOI:10.1080/00221689309498848

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A simple mathematical model describing the operation of a hydraulic ram is presented. Predictions of the model are compared with measurements done in an earlier stage of the project. The model is used to perform a parameter variation study.

ISSN:0022-1686    

DOI:10.1080/00221689309498849

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor