scholarly journals Interaction of buoyant plumes in open-channel flow

1992 ◽  
Vol 33 (4) ◽  
pp. 451-473
Author(s):  
P. J. Wicks
Keyword(s):  
Diffusion Equation ◽  
Channel Flow ◽  
Open Channel ◽  
Nonlinear Term ◽  
Initial Conditions ◽  
Hermite Polynomials ◽  
Open Channel Flow ◽  
The Other ◽  
Buoyant Plumes ◽  
Rich Variety

AbstractIn this paper, a model for lateral dispersion in open-channel flow is studied involving a diffusion equation which has a nonlinear term describing the effect of buoyancy. The model is used to investigate the interaction of two buoyant pollutant plumes. An approximate analytic technique involving Hermite polynomials is applied to the resulting PDEs to reduce them to a system of ODEs for the centroids and widths of the two plumes. The ODEs are then solved numerically. A rich variety of behaviour occurs depending on the relative positions, widths and strengths of the initial discharges. It is found that for two plumes of equal strength and width discharged side-by-side, the plumes move apart and the rate of spreading is inhibited by their interaction, whereas when one plume is initially much wider than the other, both plumes tend to drift to the side of the narrower plume. Finally, the PDEs are solved numerically for two sets of initial conditions and a comparison is made with the ODE solutions. Agreement is found to be good.

Finite element modeling of surge propagation and an application to the Hay River, N.W.T.

1992 ◽  
Vol 19 (3) ◽  
pp. 454-462 ◽  
Author(s):  
F. E. Hicks ◽  
P. M. Steffler ◽  
R. Gerard
Keyword(s):  
Finite Element ◽  
Channel Flow ◽  
Open Channel ◽  
Initial Conditions ◽  
Open Channel Flow ◽  
Kinematic Wave ◽  
Finite Element Scheme ◽  
Flow Problems ◽  
Ice Jam

This paper describes the application of the characteristic-dissipative-Galerkin method to steady and unsteady open channel flow problems. The robust performance of this new finite element scheme is demonstrated in modeling the propagation of ice jam release surges over a 500 km reach of the Hay River in Alberta and Northwest Territories. This demonstration includes the automatic determination of steady flow profiles through supercritical–subcritical transitions, establishing the initial conditions for the unsteady flow analyses. The ice jam releases create a dambreak type of problem which begins as a very dynamic situation then develops into an essentially kinematic wave problem as the disturbance propagated downstream. The characteristic-dissipative-Galerkin scheme provided stable solutions not only for the extremes of dynamic and kinematic wave conditions, but also through the transition between the two. Key words: open channel flow, finite element method, dam break, surge propagation.

scholarly journals Experimental Investigation of Turbulence Diffusion—A Factor in Transportation of Sediment in Open-Channel Flow

1945 ◽  
Vol 12 (2) ◽  
pp. A91-A100
Author(s):  
E. R. Van Driest
Keyword(s):  
Experimental Investigation ◽  
Channel Flow ◽  
Open Channel ◽  
Open Channel Flow ◽  
The Other ◽  
Immiscible Fluid ◽  
Mean Square ◽  
Velocity Correlation ◽  
Correlation Curve ◽  
The Mean

Abstract Turbulence diffusion in open-channel flow was investigated experimentally by photographing the spread of globules formed by the injection of an immiscible fluid into water. The mean-square transverse deviations of the globules at various distances downstream from the source were computed and analyzed in an effort to determine the shape of the velocity-correlation curve. Comparison was made between two types of curve which fitted the deviation data, one corresponding to a power-correlation law and the other to an exponential-correlation law.

Hydraulics of culvert fishways V: Alberta fish weirs and baffles

1990 ◽  
Vol 17 (6) ◽  
pp. 1015-1021 ◽  
Author(s):  
N. Rajaratnam ◽  
C. Katopodis ◽  
M. A. Fairbairn
Keyword(s):  
Turbulent Flow ◽  
Key Words ◽  
Channel Flow ◽  
Laboratory Study ◽  
Open Channel ◽  
Open Channel Flow ◽  
Hydraulic Performance ◽  
The Other ◽  
Other Hand ◽  
Flow Hydraulics

This paper presents the results of a laboratory study of the hydraulic performance of fish weirs and fish baffles used by Alberta Transportation for improving the fish-passing capacity of culverts. It was found that if the longitudinal spacing of the weirs is limited to 0.6 and 1.2 times the diameter of the culvert, their performance is comparable to that of the corresponding weir and slotted-weir baffle systems, with regard to the depth of pool between the baffles as well as the barrier velocity. On the other hand, the fish baffles did not perform as well as the fish weirs under the conditions tested. Key words: culverts, fishways, baffles, turbulent flow, hydraulics, open-channel flow.

MODELING THE ORGANIC REMOVAL AND OXYGEN CONSUMPTION BY BIOFILMS IN AN OPEN-CHANNEL FLOW

1994 ◽  
Vol 30 (2) ◽  
pp. 53-61 ◽  
Author(s):  
Shiyu Li ◽  
Guang Hao Chen
Keyword(s):  
Water Quality ◽  
Oxygen Consumption ◽  
River Water ◽  
Channel Flow ◽  
Diffusion Layer ◽  
Open Channel ◽  
Open Channel Flow ◽  
River Water Quality ◽  
Monod Kinetics ◽  
Organic Removal

A mathematical model is proposed to predict the removal of dissolved organic substances and the consumption of dissolved oxygen by attached biofilms in an open-channel flow. The model combines the biofilm equations with the conventional Streeter–Phelps type equations of river water quality by considering the mass transfer of organics and oxygen in the river water through the diffusion layer into the biofilm. It is assumed that the diffusion and reaction within the biofilm are of steady-state, and follow Monod kinetics. The model is solved numerically with a trial-and-error method. The simulation results of the model for an ideal case of river flow and biofilm show that the organic removal rate and oxygen consumption rate caused by the biofilm are greater than that by suspended biomass. The effects of diffusion layer thickness, flow velocity, and biofilm thickness on the change of river water quality are discussed.

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