Three-dimensional velocity measurements around bridge piers in gravel bed

2017 ◽  
Vol 36 (6) ◽  
pp. 663-676 ◽  
Author(s):  
Manish Pandey ◽  
P. K. Sharma ◽  
Z. Ahmad ◽  
Umesh Kumar Singh ◽  
Nilav Karna
Keyword(s):  
Three Dimensional ◽  
Bridge Piers ◽  
Velocity Measurements ◽  
Gravel Bed

Simulation of Three-Dimensional Flow Field Around Unconventional Bridge Piers

2017 ◽  
Author(s):  
Adnan Ismael ◽  
Hamid Hussein ◽  
Mohammed Tareq ◽  
Mustafa Gunal
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Bridge Piers ◽  
Three Dimensional Flow ◽  
Dimensional Flow

Operational Model and its Validation with Drift Tests in Water Areas Around the Baltic Sea

1994 ◽  
Vol 29 (2-3) ◽  
pp. 293-308
Author(s):  
J. Koponen ◽  
M. Virtanen ◽  
H. Vepsä ◽  
E. Alasaarela
Keyword(s):  
Three Dimensional ◽  
Fast Response ◽  
Velocity Measurements ◽  
Short Term ◽  
Large Lakes ◽  
Operational Model ◽  
Water Currents ◽  
Emergency Situations ◽  
Sensitivity Tests ◽  
The Baltic

Abstract Three-dimensional (3-D) mathematical models of water currents, transport, mixing, reaction kinetic, and interactions with bottom and air have been used in Finland regularly since 1982 and applied to about 40 cases in large lakes, inland seas and their coastal waters. In each case, model validity has been carefully tested with available flow velocity measurements, tracer studies and water quality observations. For operational use, i.e., for spill combatting and sea rescue, the models need fast response, proven validity and illustrative visualization. In 1987-90, validated models were implemented for operational use at five sea areas along the Finnish coast. Further validation was obtained in model applications from nine documented or arranged cases and from seven emergency situations. Sensitivity tests supplement short-term validation. In the Bothnian Sea, it was nescessary to start the calculation of water currents three days prior to the start of the experiment to reduce initial inaccuracies and to make the coastal transport estimates meaningful.

Three Dimensional Numerical Analyses of Bridge Piled-Raft Foundation under Riverbed Erosion

2012 ◽  
Vol 178-181 ◽  
pp. 2373-2377 ◽  
Author(s):  
Wen Tsung Liu ◽  
Yi Yi Li
Keyword(s):  
Bearing Capacity ◽  
Three Dimensional ◽  
Fem Analysis ◽  
Bridge Piers ◽  
Piled Raft Foundation ◽  
River Erosion ◽  
Dimensional Finite Element ◽  
The Face ◽  
Three Dimensional Finite Element

From the 921 earthquake to the major typhoons, including the Morakot typhoon, they damaged original landscape of rivers in Taiwan. In recent years, it alleged that abutment bridge exposed to the most serious security problems. Because of bridge piers in addition to the face of long-term river erosion, the flood on the pier will produce localized erosion near the bridge. The pier will be due to inadequate bearing capacity, resulting in subsidence, displacement, bridge version accompanied by tilting and even caving. The river erosion of soil around the piers deposits and production of contraction will often reduce the bearing capacity. Therefore, how to accurately estimate the scour depth, calculate piers to withstand water impact and analyses its stability for preventing injuries in the first place is the current pressing issues. In this study, three-dimensional finite element method (FEM) analysis program Plaxis 3D foundation is used. Polaris second bridge is selected for analysis. Based on local scouring of the model and various numerical variable conditions, the parameter of bridge pier is studied.

The two-sided lid-driven cavity: experiments on stationary and time-dependent flows

2002 ◽  
Vol 450 ◽  
pp. 67-95 ◽  
Author(s):  
CH. BLOHM ◽  
H. C. KUHLMANN
Keyword(s):  
Three Dimensional ◽  
Standing Waves ◽  
Reynolds Numbers ◽  
Time Dependent ◽  
Flow State ◽  
Incompressible Fluid Flow ◽  
Velocity Measurements ◽  
Driven Cavity ◽  
Rectangular Container ◽  
Hot Film

The incompressible fluid flow in a rectangular container driven by two facing sidewalls which move steadily in anti-parallel directions is investigated experimentally for Reynolds numbers up to 1200. The moving sidewalls are realized by two rotating cylinders of large radii tightly closing the cavity. The distance between the moving walls relative to the height of the cavity (aspect ratio) is Γ = 1.96. Laser-Doppler and hot-film techniques are employed to measure steady and time-dependent vortex flows. Beyond a first threshold robust, steady, three-dimensional cells bifurcate supercritically out of the basic flow state. Through a further instability the cellular flow becomes unstable to oscillations in the form of standing waves with the same wavelength as the underlying cellular flow. If both sidewalls move with the same velocity (symmetrical driving), the oscillatory instability is found to be tricritical. The dependence on two sidewall Reynolds numbers of the ranges of existence of steady and oscillatory cellular flows is explored. Flow symmetries and quantitative velocity measurements are presented for representative cases.

Three-Dimensional Concentration and Velocity Measurements of a Pulsatile Contaminant Release in a Model of Oklahoma City

2021 ◽  
Author(s):  
Daniel Chung ◽  
Lynne Mooradian ◽  
Joshua Rhee ◽  
Michael Benson ◽  
Christopher J. Elkins ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Oklahoma City ◽  
Velocity Measurements ◽  
Contaminant Release

Three-dimensional numerical simulations of local scouring around bridge piers

2017 ◽  
Vol 56 (3) ◽  
pp. 351-366 ◽  
Author(s):  
Yafei Jia ◽  
Mustafa Altinakar ◽  
M. Sukru Guney
Keyword(s):  
Numerical Simulations ◽  
Three Dimensional ◽  
Bridge Piers

Temporal variations in bedload transport rates and sediment storage in gravel-bed rivers

1992 ◽  
Vol 16 (3) ◽  
pp. 319-338 ◽  
Author(s):  
Trevor Hoey
Keyword(s):  
Three Dimensional ◽  
Temporal Variations ◽  
Sampling Interval ◽  
Bedload Transport ◽  
Sediment Storage ◽  
Data Set ◽  
Gravel Bed ◽  
Wide Range ◽  
Gravel Bed Rivers ◽  
Bed Waves

Temporal variability in bedload transport rates and spatial variability in sediment storage have been reported with increasing frequency in recent years. A spatial and temporal classification for these features is suggested based on the gravel bedform classification of Church and Jones (1982). The identified scales, meso-, macro-, and mega- are each broad, and within each there is a wide range of processes acting to produce bedload fluctuations. Sampling the same data set with different sampling intervals yields a near linear relationship between sampling interval and pulse period. A range of modelling strategies has been applied to bed waves. The most successful have been those which allow for the three-dimensional nature of sediment storage processes, and which allow changes in the width and depth of stored sediment. The existence of bed waves makes equilibrium in gravel-bed rivers necessarily dynamic. Bedload pulses and bed waves can be regarded as equilibrium forms at sufficiently long timescales.

scholarly journals Calculation of acoustic flow-rate measurements error with the help of Fermat’s principle

2018 ◽  
Vol 211 ◽  
pp. 04007
Author(s):  
Alexander Petrov ◽  
Semyon Shkundin
Keyword(s):  
Control Systems ◽  
Cross Section ◽  
Flow Rate ◽  
Three Dimensional ◽  
Air Flow Rate ◽  
Velocity Measurements ◽  
Three Dimensional Flow ◽  
Automatic Control Systems ◽  
A Value ◽  
Flow Changes

The establishment of dispatching and automatic control systems for mine ventilation is impossible without the availability of perfect air flow rate sensors. Existing anemometers (tachometer, heat) do not meet these requirements. The error of average in cross section velocity measurements with such sensors reaches 15-20, sometimes 30%. The reason - the speed measured at one point is interpreted as the average over the cross section. The reliability of the sensors is small, because they are exposed to the damaging effect of a dusty atmosphere. Stationary installed anemometers clutter cross section, which is not always allowed. Fermat’s variational principle is used for derivation of the formula for the time of propagation of a sonic signal between two set points A and B in a steady three-dimensional flow of a fluid or gas. It is shown that the fluid flow changes the time of signal reception by a value proportional to the flow rate independently of the velocity profile. The time difference in the reception of the signals from point B to point A and vice versa is proportional with a high accuracy to the flow rate. It is shown that the relative error of the formula does not exceed the square of the largest Mach number. This makes it possible to measure the flow rate of a fluid or gas with an arbitrary steady subsonic velocity field

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