Velocity distributions near the inlet of corrugated steel pipe culverts

2012 ◽  
Vol 39 (12) ◽  
pp. 1243-1251 ◽  
Author(s):  
Martin Hunt ◽  
Shawn Clark ◽  
Rob Tkach
Keyword(s):  
Velocity Field ◽  
Recirculation Zone ◽  
Velocity Structure ◽  
Three Dimensional ◽  
Shear Zones ◽  
Fish Passage ◽  
Steel Pipe ◽  
Low Velocity ◽  
Velocity Flow ◽  
Percent Area

This paper presents the findings of a study examining the velocity field within the inlet region of a corrugated steel pipe (CSP) culvert model with vertical headwall, 45° wingwall, and projecting end inlet treatments. Also examined are the effects of embedding the culvert below the stream bed and backfilling the culvert with granular material. Three-dimensional velocity distributions were measured in an effort to better understand how these inlet treatments may affect fish passage. The study examined velocity structure within a CSP culvert with a diameter of 0.8 m at a flow rate of 0.175 m3/s. Measurements were recorded using acoustic Doppler velocimeters at four locations; 0.25, 0.5, 1, and 2 diameters downstream of the inlet. The velocity field of each inlet configuration was dominated by a central jet of high velocity flow surrounded by a low velocity recirculation zone. Analysis of the percent area less than Uavg for each inlet treatment found that the projecting end configuration contained the largest low velocity zone. The usefulness of the low velocity recirculation zone as a fish passage corridor may however be limited by the presence of significant vertical and spanwise velocities as well as high shear zones.

scholarly journals P-wave crustal tomography of Greece with use of an accurate two-point ray tracer

1997 ◽  
Vol 40 (1) ◽  
Author(s):  
G. Drakatos ◽  
G. Karantonis ◽  
G. N. Stavrakakis
Keyword(s):  
Large Scale ◽  
Velocity Structure ◽  
Three Dimensional ◽  
Seismic Energy ◽  
Aegean Sea ◽  
P Wave ◽  
Low Velocity ◽  
Aegean Area ◽  
Arrival Times ◽  
Horizontal Variations

The three-dimensional velocity structure of the crust in the Aegean sea and the surrounding regions (34.0º-42.OºN, 19.0ºE-29.0ºE) is investigated by inversion of about 10000 residuals of arrival times of P-wave from local events. The resulting velocity structure shows strong horizontal variations due to the complicated crustal structure and the variations of crustal thickness. The northern part of the region generally shows high velocities. In the inner part of the volcanic arc (Southern Aegean area), relatively low velocities are observed, suggesting a large-scale absorption of seismic energy as confirmed by the low seismicity of the region. A low velocity zone was observed along the subduction zone of the region, up to a depth of 4 km. The existence of such a zone could be due to granitic or other intrusions in the crust during the uplift of the region during Alpidic orogenesis.

Three-Dimensional Recirculation Flow in a Backward Facing Step

1994 ◽  
Vol 116 (2) ◽  
pp. 228-232 ◽  
Author(s):  
Chiang Shih ◽  
Chih-Ming Ho
Keyword(s):  
Velocity Field ◽  
Aspect Ratio ◽  
Recirculation Zone ◽  
Three Dimensional ◽  
Laser Doppler Anemometer ◽  
Separation Region ◽  
Two Dimensional ◽  
Small Aspect Ratio ◽  
Backward Facing Step ◽  
Recirculation Flow

The flow field behind a small aspect ratio (channel width/step height = 3) backward-facing step is examined using laser Doppler anemometer. All three velocity components inside the separation region are surveyed in detail. The velocity profile just upstream of the step is laminar and two-dimensional. The velocity field reveals that the reattachment and the flow in the recirculation zone are highly three-dimensional due to the small aspect ratio.

scholarly journals VELOCITY PROFILE VISUALIZATION OF WATER NATURAL PERCOLATION IN A POROUS MEDIUM

2009 ◽  
Vol 8 (1) ◽  
pp. 31 ◽  
Author(s):  
A. C. França ◽  
L. R. Carrocci ◽  
A. F. Siqueira
Keyword(s):  
Porous Medium ◽  
Gravitational Force ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Low Velocity ◽  
Velocity Flow ◽  
Water Percolation ◽  
Flow Through ◽  
Physical Phenomena ◽  
Capillary Phenomenon

This paper aims to show the profile and the behavior of the velocity of the water flow through a porous medium composed of clay and sand aggregated by burning in an oil furnace. The work models mathematics based on the Navier-Stokes differential equation, which represents the behavior of the water velocity flow in porous medium taking into account parameters of a low velocity laminar flow, increased load loss value and Number of Reynolds > 1. Physical phenomena such as porosity, permeability, particles arrangement, radius and wet perimeter are considered in the equation. The study shows the three-dimensional profile of the water percolation velocity which, originated from the capillary phenomenon, causes a sum of the tensions of increased values able to produce cracks in the medium structure. And, differently from filtration phenomenon, which overcomes the capillarity of the medium by the gravitational force or by efforts applied aiming to increase the flow velocity, the natural percolation opposes to the gravity and to the surrounding pressure moving slowly, reaching the flow at 30 and 40 centimeters depending on the permeability of the porous medium.

scholarly journals Partitioning the Universe into gravitational basins using the cosmic velocity field

2019 ◽  
Vol 489 (1) ◽  
pp. L1-L6 ◽  
Author(s):  
Alexandra Dupuy ◽  
Helene M Courtois ◽  
Florent Dupont ◽  
Florence Denis ◽  
Romain Graziani ◽  
...  
Keyword(s):  
Velocity Field ◽  
Observational Data ◽  
Large Scale ◽  
Three Dimensional ◽  
Flow Lines ◽  
Local Universe ◽  
New Approach ◽  
Large Scale Structures ◽  
Peculiar Velocity ◽  
Velocity Flow

ABSTRACT This letter presents a new approach using the cosmic peculiar velocity field to characterize the morphology and size of large-scale structures in the local Universe. The algorithm developed uses the three-dimensional peculiar velocity field to compute flow lines, or streamlines. The local Universe is then partitioned into volumes corresponding to gravitational basins, also called watersheds, among the different end points of the velocity flow lines. This new methodology is first tested on numerical cosmological simulations, used as benchmark for the method, and then applied to the Cosmic-Flows project observational data in order to pay particular attention to the nearby superclusters including ours. More extensive tests on both simulated and observational data will be discussed in an accompanying paper.

Numerical study of an innovative fish ladder design for perched culverts

2016 ◽  
Vol 43 (2) ◽  
pp. 173-181 ◽  
Author(s):  
Jason M. Duguay ◽  
R.W. Jay Lacey
Keyword(s):  
Recirculation Zone ◽  
Numerical Study ◽  
Fish Habitat ◽  
Fish Passage ◽  
Dynamics Model ◽  
Low Velocity ◽  
Computational Fluid Dynamics Model ◽  
Fish Ladder ◽  
Physical Prototype ◽  
High Flows

A fish ladder designed to facilitate fish passage at the outlet end of perched culverts is investigated with a 3D computational fluid dynamics model. The fish ladder consists of a series of alternating arch baffles with geometries providing options for fish passage over varying flow and debris conditions within the ladder. At high flows, the baffle’s protruding center arch increases pool depth, reducing the volumetric bulk turbulence of the pools and improving fish habitat. The arch baffle is compared to a standard baffle design currently in use and demonstrates potential advantages for fish passage. A recirculation zone of low velocity occupies a large volume of the pool believed to provide appropriate hydraulic habitat for resting and staging jump attempts upstream. This numerical study provides an acceptable design for future physical prototype testing in the laboratory or field to verify hydraulics and evaluate fish passage effectiveness.

scholarly journals Interactions between Tandem Cylinders in an Open Channel: Impact on Mean and Turbulent Flow Characteristics

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1718
Author(s):  
Hasan Zobeyer ◽  
Abul B. M. Baki ◽  
Saika Nowshin Nowrin
Keyword(s):  
Turbulent Flow ◽  
Open Channel ◽  
Recirculation Zone ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Flow Recirculation ◽  
Tandem Cylinders ◽  
Flow Development ◽  
The Mean ◽  
Recirculation Length

The flow hydrodynamics around a single cylinder differ significantly from the flow fields around two cylinders in a tandem or side-by-side arrangement. In this study, the experimental results on the mean and turbulence characteristics of flow generated by a pair of cylinders placed in tandem in an open-channel flume are presented. An acoustic Doppler velocimeter (ADV) was used to measure the instantaneous three-dimensional velocity components. This study investigated the effect of cylinder spacing at 3D, 6D, and 9D (center to center) distances on the mean and turbulent flow profiles and the distribution of near-bed shear stress behind the tandem cylinders in the plane of symmetry, where D is the cylinder diameter. The results revealed that the downstream cylinder influenced the flow development between cylinders (i.e., midstream) with 3D, 6D, and 9D spacing. However, the downstream cylinder controlled the flow recirculation length midstream for the 3D distance and showed zero interruption in the 6D and 9D distances. The peak of the turbulent metrics generally occurred near the end of the recirculation zone in all scenarios.

scholarly journals Energy Loss in Steep Open Channels with Step-Pools

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 72
Author(s):  
Suresh Kumar Thappeta ◽  
S. Murty Bhallamudi ◽  
Venu Chandra ◽  
Peter Fiener ◽  
Abul Basar M. Baki
Keyword(s):  
Energy Loss ◽  
Flow Rate ◽  
Recirculation Zone ◽  
Three Dimensional ◽  
Nonlinear Function ◽  
Open Channels ◽  
Geometrical Parameters ◽  
Transition Flow ◽  
Cumulative Energy ◽  
Zone Velocity

Three-dimensional numerical simulations were performed for different flow rates and various geometrical parameters of step-pools in steep open channels to gain insight into the occurrence of energy loss and its dependence on the flow structure. For a given channel with step-pools, energy loss varied only marginally with increasing flow rate in the nappe and transition flow regimes, while it increased in the skimming regime. Energy loss is positively correlated with the size of the recirculation zone, velocity in the recirculation zone and the vorticity. For the same flow rate, energy loss increased by 31.6% when the horizontal face inclination increased from 2° to 10°, while it decreased by 58.6% when the vertical face inclination increased from 40° to 70°. In a channel with several step-pools, cumulative energy loss is linearly related to the number of step-pools, for nappe and transition flows. However, it is a nonlinear function for skimming flows.

Sign in / Sign up

Export Citation Format

Share Document