Turbulence Modelling of Suspended Sediment in the Surf Zone
A computational model is developed for the prediction of the wave period averaged turbulence structure under a breaking wave. The principal forcing function for the model is the generation...

Modeling Emissions from Aerobic Treatment Systems
A mathematical model has been developed specifically for accurately quantifying the dispersion of emissions in the near vicinity of a groundlevel area source. This model accounts for variations...

Influence of Hydrodynamics on Biofilm Accumulation
The influence of hydrodynamics on biofilm thickness was investigated under laminar and turbulent flow conditions. The maximum biofilm thickness was found within the transition region between...

Calculation of Three-Dimensional Turbulent Flow in Francis Turbine Runner
A numerical scheme, based on MacCormack's predictor-corrector explicit finite volume method, for solving three-dimensional weakly compressible inviscid, laminar, and turbulent...

Development of a New Hydraulic Design Tool for Spiral Casing/Distributor Geometry
A novel computational model has been developed to predict highly complex turbulent flow in a combined spiral casing/distributor geometry. Validation of the computational model against...

Numerical Modeling of Air/Water Mixtures for Internal Flows
The Tennessee Valley Authority (TVA) currently is working with several organizations to develop design tools for the aerating hydroturbine. Part of this effort includes the investigation...

Temperature Rise, Bank Erosion, and Jet Velocity Effects of Submerged Multiport Diffusers in an Estuary
Temperature distributions, potential bank erosion, and jet velocity and trajectory of submerged multiport diffusers were predicted as part of the permitting process for an fossil fuel...

Investigations on 3-D Flow Structures in Combined Systems of Groynes and Harbour Basins
The structure of the flow field in harbour basins shows significant three-dimensional (3-D) effects, e.g. variation of the direction of the horizontal velocity components with depth, existence...

Turbulence and Reynolds Stress Distribution in a Natural River
Turbulence characteristics of ambient flow velocities and their comparison with those generated by the movement of barge traffic within the channel border area in a navigation waterway...

Diffuser Design for Water Quality-Based Toxics Control
U.S. Environmental Protection Agency regulations require that the discharge of toxic pollutants to the waters of the United States be controlled. These regulatory requirements have made...

Air-Water Transfer: The Role of Partitioning
A review is presented of the role of air-water equilibrium in determining the direction and rate of transfer of chemicals between water bodies and the atmosphere. Because this diffusive...

The Effect of Surface Films on Concentration Fluctuations Close to a Gas/Liquid Interface
Modeling of gas/liquid mass transport requires knowledge concerning the behavior of near-surface concentration fluctuations at clean and film-covered gas/liquid interfaces. Previous measurements...

Effect of Temperature on Gas Transfer at Low Surface Renewal Rates
In order to investigate the dependence of gas transfer coefficients on temperature under conditions of low surface renewal rates, laboratory experiments were conducted using simultaneous...

Turbulent Velocity and Gas Concentration Measurements in the Near-Surface Layer
An experiment was undertaken to study the mechanism of interfacial mass transfer. Near-surface liquid turbulence and oxygen concentration fluctuations have been measured in a grid-stirred...

Development of Method for Measuring Near-Surface Turbulence
New techniques for tracking particles in fluid are presented. A method to make micro-capsules which are filled with pure water and covered with a thin film of polystyrene is developed....

Measurement of Wave-Induced Turbulent Flow Structures Using Digital Image Sequence Analysis
The turbulent flow in water close to the wavy wind-stressed water surface has been examined quantitatively in a large circular wind-water tunnel with a flow visualization method using...

A Fluorescence Technique to Measure Concentration Gradients near an Interface
A new fluorescence technique which measures the concentration profile in a mass transfer boundary layer is described. It uses a tracer whose fluorescent intensity is inversely proportional...

Rainfall-Reaeration Effects
The effect of rainfall intensity on reaeration has not been adequately reported in the literature. It is clear that rainfall causes surface turbulence and increases reaeration, and a significant...

Oxygen Transfer in Turbulent Shear Flows
Oxygen transfer equation for the air-water two-phase aeration region of turbulent shear flow in a vertical pipe is derived. Dimensionless variables significant in characterizing the transfer...

Turbulence Level Below the Waves and Its Relation to Absorption
A review of recent experimental studies carried out on gas transfer at water surfaces in various situations shows that the absorption coefficient is better related to the turbulence level...

 

 

 

 

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