scholarly journals BUOYANT DISCHARGES FROM SUBMERGED MULTIPORT DIFFUSERS

1974 ◽  
Vol 1 (14) ◽  
pp. 126
Author(s):  
Donald R.F. Harleman ◽  
Gerhard H. Jirka
Keyword(s):  
Channel Model ◽  
Coastal Zone Management ◽  
Three Dimensional ◽  
Cooling Water ◽  
Frictional Resistance ◽  
Two Dimensional ◽  
Buoyant Jet ◽  
Buoyant Jets ◽  
Dimensional Flow ◽  
Zone Management

The application of submerged multiport diffusers for the discharge of degradable liquid wastes and of heated cooling water from electric power generation forms an important aspect of coastal zone management. Previous buoyant jet models for submerged diffuser discharge have been developed for the limiting case of discharge in unconfined deep water in the form of rising buoyant jets. These models can be used for sewage diffusers, but are not applicable for diffusers in shallow receiving water with low buoyancy, the type used for thermal discharges ("thermal diffusers"). A multiport diffuser will produce a general three-dimensional flow. Yet the predominantly two dimensional flow which exists in the center portion of the three-dimensional diffuser can be analyzed as a two-dimensional "channel model". Theoretical solutions for diffuser-induced dilutions are derived for the two-dimensional case and verified experimentally. Furthermore, the theory can be applied to the three-dimensional situation by requiring equivalency of far-field effects, that is the frictional resistance governing the diffuser-induced motion at larger distances from the diffuser line.

Contracting ducts of finite length

1951 ◽  
Vol 2 (4) ◽  
pp. 254-271 ◽  
Author(s):  
L. G. Whitehead ◽  
L. Y. Wu ◽  
M. H. L. Waters
Keyword(s):  
Stream Function ◽  
Finite Length ◽  
Velocity Potential ◽  
Three Dimensional ◽  
Relaxation Method ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Hodograph Plane ◽  
Two Dimensional Flow ◽  
Working Section

SummmaryA method of design is given for wind tunnel contractions for two-dimensional flow and for flow with axial symmetry. The two-dimensional designs are based on a boundary chosen in the hodograph plane for which the flow is found by the method of images. The three-dimensional method uses the velocity potential and the stream function of the two-dimensional flow as independent variables and the equation for the three-dimensional stream function is solved approximately. The accuracy of the approximate method is checked by comparison with a solution obtained by Southwell's relaxation method.In both the two and the three-dimensional designs the curved wall is of finite length with parallel sections upstream and downstream. The effects of the parallel parts of the channel on the rise of pressure near the wall at the start of the contraction and on the velocity distribution across the working section can therefore be estimated.

Three-dimensional flow in cavities

1963 ◽  
Vol 16 (4) ◽  
pp. 620-632 ◽  
Author(s):  
D. J. Maull ◽  
L. F. East
Keyword(s):  
Static Pressure ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Large Span ◽  
Dimensional Flow ◽  
Pressure Distributions ◽  
Oil Flow ◽  
Two Dimensional Flow

The flow inside rectangular and other cavities in a wall has been investigated at low subsonic velocities using oil flow and surface static-pressure distributions. Evidence has been found of regular three-dimensional flows in cavities with large span-to-chord ratios which would normally be considered to have two-dimensional flow near their centre-lines. The dependence of the steadiness of the flow upon the cavity's span as well as its chord and depth has also been observed.

Cellular flow in a partially filled rotating drum: regular and chaotic advection

2017 ◽  
Vol 825 ◽  
pp. 631-650 ◽  
Author(s):  
Francesco Romanò ◽  
Arash Hajisharifi ◽  
Hendrik C. Kuhlmann
Keyword(s):  
Three Dimensional ◽  
Reynolds Numbers ◽  
Chaotic Advection ◽  
Two Dimensional ◽  
Rotating Drum ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Heteroclinic Connection ◽  
Two Dimensional Flow ◽  
Chaotic Streamlines

The topology of the incompressible steady three-dimensional flow in a partially filled cylindrical rotating drum, infinitely extended along its axis, is investigated numerically for a ratio of pool depth to radius of 0.2. In the limit of vanishing Froude and capillary numbers, the liquid–gas interface remains flat and the two-dimensional flow becomes unstable to steady three-dimensional convection cells. The Lagrangian transport in the cellular flow is organised by periodic spiralling-in and spiralling-out saddle foci, and by saddle limit cycles. Chaotic advection is caused by a breakup of a degenerate heteroclinic connection between the two saddle foci when the flow becomes three-dimensional. On increasing the Reynolds number, chaotic streamlines invade the cells from the cell boundary and from the interior along the broken heteroclinic connection. This trend is made evident by computing the Kolmogorov–Arnold–Moser tori for five supercritical Reynolds numbers.

Reconstruction of three-dimensional flow fields from two-dimensional data

2020 ◽  
Vol 407 ◽  
pp. 109239
Author(s):  
José Miguel Pérez ◽  
Soledad Le Clainche ◽  
José Manuel Vega
Keyword(s):  
Three Dimensional ◽  
Flow Fields ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Dimensional Flow

Three-Dimensional Buoyant Wall Jets Released Into a Coflowing Turbulent Boundary Layer

1990 ◽  
Vol 112 (2) ◽  
pp. 356-362 ◽  
Author(s):  
J. R. Sinclair ◽  
P. R. Slawson ◽  
G. A. Davidson
Keyword(s):  
Three Dimensional ◽  
Ground Level ◽  
Turbulent Shear ◽  
Wall Jet ◽  
Turbulent Shear Flow ◽  
Streamwise Vorticity ◽  
Buoyant Jet ◽  
Buoyant Jets ◽  
Jet Trajectory ◽  
Model Predictions

Experiments have been conducted in a water flume to simulate finite-length line sources of heat that issue horizontally at ground level into a coflowing turbulent shear flow. The downstream development of each buoyant jet is documented by detailed mean temperature measurements, which are analyzed to determine the jet trajectory, spread rates, and distance to the point of liftoff from the surface. In addition, a three-dimensional, parabolic, numerical model based on the fundamental conservation equations is developed. Model predictions of several buoyant jets compare reasonably with the experimental data and suggest that the strength of the streamwise vorticity plays an important role in governing liftoff of a buoyant wall jet from the surface.

Theoretical Aspects of Thrust Vector Control by Secondary Gas Injection in Rocket Nozzles

1968 ◽  
Vol 72 (686) ◽  
pp. 171-177 ◽  
Author(s):  
John H. Neilson ◽  
Alastair Gilchrist ◽  
Chee K. Lee
Keyword(s):  
Vector Control ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Side Force ◽  
Thrust Vector Control ◽  
Dimensional Flow ◽  
Two Dimensional Flow ◽  
Thrust Vector ◽  
Secondary Injection

This work deals with theoretical aspects of thrust vector control in rocket nozzles by the injection of secondary gas into the supersonic region of the nozzle. The work is concerned mainly with two-dimensional flow, though some aspects of three-dimensional flow in axisymmetric nozzles are considered. The subject matter is divided into three parts. In Part I, the side force produced when a physical wedge is placed into the exit of a two-dimensional nozzle is considered. In Parts 2 and 3, the physical wedge is replaced by a wedge-shaped “dead water” region produced by the separation of the boundary layer upstream of a secondary injection port. The modifications which then have to be made to the theoretical relationships, given in Part 1, are enumerated. Theoretical relationships for side force, thrust augmentation and magnification parameter for two- and three-dimensional flow are given for secondary injection normal to the main nozzle axis. In addition, the advantages to be gained by secondary injection in an upstream direction are clearly illustrated. The theoretical results are compared with experimental work and a comparison is made with the theories of other workers.

scholarly journals Volumetric imaging of shark tail hydrodynamics reveals a three-dimensional dual-ring vortex wake structure

2011 ◽  
Vol 278 (1725) ◽  
pp. 3670-3678 ◽  
Author(s):  
Brooke E. Flammang ◽  
George V. Lauder ◽  
Daniel R. Troolin ◽  
Tyson Strand
Keyword(s):  
Three Dimensional ◽  
Flow Patterns ◽  
Wake Flow ◽  
Ring Vortex ◽  
Vortex Wake ◽  
Two Dimensional ◽  
Volumetric Imaging ◽  
Dimensional Flow ◽  
Classic Problem ◽  
Two Dimensional Flow

Understanding how moving organisms generate locomotor forces is fundamental to the analysis of aerodynamic and hydrodynamic flow patterns that are generated during body and appendage oscillation. In the past, this has been accomplished using two-dimensional planar techniques that require reconstruction of three-dimensional flow patterns. We have applied a new, fully three-dimensional, volumetric imaging technique that allows instantaneous capture of wake flow patterns, to a classic problem in functional vertebrate biology: the function of the asymmetrical (heterocercal) tail of swimming sharks to capture the vorticity field within the volume swept by the tail. These data were used to test a previous three-dimensional reconstruction of the shark vortex wake estimated from two-dimensional flow analyses, and show that the volumetric approach reveals a different vortex wake not previously reconstructed from two-dimensional slices. The hydrodynamic wake consists of one set of dual-linked vortex rings produced per half tail beat. In addition, we use a simple passive shark-tail model under robotic control to show that the three-dimensional wake flows of the robotic tail differ from the active tail motion of a live shark, suggesting that active control of kinematics and tail stiffness plays a substantial role in the production of wake vortical patterns.

Extension of the Prandtl–Batchelor theorem to three-dimensional flows slowly varying in one direction

2010 ◽  
Vol 654 ◽  
pp. 351-361 ◽  
Author(s):  
M. SANDOVAL ◽  
S. CHERNYSHENKO
Keyword(s):  
Flow Field ◽  
Small Parameter ◽  
Order Approximation ◽  
Three Dimensional ◽  
Inviscid Limit ◽  
Two Dimensional ◽  
Leading Order ◽  
Dimensional Flow ◽  
Two Dimensional Flow

According to the Prandtl–Batchelor theorem for a steady two-dimensional flow with closed streamlines in the inviscid limit the vorticity becomes constant in the region of closed streamlines. This is not true for three-dimensional flows. However, if the variation of the flow field along one direction is slow then it is possible to expand the solution in terms of a small parameter characterizing the rate of variation of the flow field in that direction. Then in the leading-order approximation the projections of the streamlines onto planes perpendicular to that direction can be closed. Under these circumstances the extension of the Prandtl–Batchelor theorem is obtained. The resulting equations turned out to be a three-dimensional analogue of the equations of the quasi-cylindrical approximation.

Three-dimensional flow images by reconstruction from two-dimensional vector velocity maps

1995 ◽  
Vol 8 (6) ◽  
pp. 915-923 ◽  
Author(s):  
Laurence N. Bohs ◽  
Barry H. Friemel ◽  
Joseph Kisslo ◽  
Daniel T. Harfe ◽  
Kathryn R. Nightingale ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Dimensional Vector ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Vector Velocity
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