The transport of health-related organic micropollutans has been a major water quality and environmental issue in the past few decades. Because of their high toxicity, long environmental half-life and high bioaccumulation factors, many of the hydrophobic organic pollutants (HOPs) are listed as priority pollutants in many countries. Although not all of the chemical and physical factors should be considered in the fate of transportation of all chemicals, a simple one-dimensional mathematical model used to simulate all of the factors was conceptually developed (Bobba et al., 1996). In that study, most important parameters needed in the model were empirically fitted. For numerical simulation of the behaviors of pollutants in the environment, it is important to provide a feasible chemical and physical transport mechanism to describe the geo-chemical and geophysical interactions involved in the system. In this study a general two-dimensional hydrodynamic numerical simulation model is developed .This model can readily extend to a three-dimensional one. The model includes all possible physical and chemical factors that might affect the transport of the pollutants. For validation and demonstration purpose, only sorption-desorption between specified dissolved organic material and phase are studied in the present study. The hydrodynamic model is verified by comparing with the reported numerical results. The numerical model then incorporates the sorption-desorption terms and the sediment effects. From the results of the simulation, the sorption-desorption mechanism and sediment scavenge effect are founded to significantly affects the pollutants fate and transport of an outfall discharge.

Abstract Jet impingement heat transfer is an enhanced heat transfer technique.This article reports results on the local heat transfer coefficients for confined impinging air jet.A transient thermochromatic liquid crystals technique is used to visualize and record isotherms on an impingement surface. Quantitative temperature measurement using thermochromatic liquid crystals is a field temperature measurement technique. It utilizes the feature that TLCs change their reflex light colors with variation of temperature and apply an image capturing and processing system to calibrate the characteristic curve of TLCs colour-temperature,and then use it to measure the distribution of surface temperature. Therefore , it can solve some problem that cannot be solved by traditional point Temperature measuring methods in heat transfer field. The main object of this articale is to set up a temperature measurement system of transient thermochromatic liquid crystals. Furthermore, an experimental is carried out in the present study to investigate the characteristics of heat transfer resulting from a low speed air jet impinging onto a horizontal circular disk confined in a vertical adiabatic cylindrical chamber. Experiments are conducted at low nozzle-to-disc spacing (0.5<H/D <3.5) and Reynolds number in the range of500 to 1500 for two different injection pips. The results show that the effects of Reynolds number and nozzle-to-disc spacing on the local heat-transfer coefficient are reported and compared with different diameter of injection pipes.Finally , empirical equations are proposed to correlate the effect of Reynolds number and nozzle-to-disc spacing .

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Vibrations of small cylinder in a jet flow are investigated experimentally. Because of the flow field in shear layers of jet flow is very complex and filled with vortex structures, so the flow induced vibration phenomena in jet flow is different from the flow induced vibration in uniform flow. The major subject in this experiment is to discuss the major cause of small cylinder vibrations, and the flow field influenced by the cylinder vibration. About flow measurement, velocity measurement by hot-wire is applied. As for the vibration measurement, by using the principle of electromagnetic, a new measurement technology was successfully developed. This new vibration measurement can measure the vibrations in two axial, so as to describe the orbit of vibrations. To find the interrelation of flow field and cylinder vibrations, flow measurement and vibration measurement was carry on at the same time. It is shown that when the jet velocity is increased constantly, small cylinder will vibration intensely. The fixed velocity is called critical velocity. If add a perturb, the vibration will occur in advance. The dominant frequency of cylinder vibration, fr, will be the same with it's nature frequency, fn, in the critical velocity, but when the flow velocity keep on increasing, the dominant frequency, fr, will also increase. Besides, the relation of reduced velocity and mass damping was found in this case. The orbits of vibrations are all like ellipse, and the orbit is different with different reduced velocity. The vibration amplitude be changed into three sections that have different reduced velocity, and different orbit. About the flow field, the velocity profile in potential core is not influenced by vibrations of small cylinder, but the velocity fluctuations in shear layer indeed be inflected. At the fixed velocity region, the dominant frequency of flow is the same with dominant frequency of vibrations when the flow at downstream of small cylinder in shear layer. This phenomena only exist when the vibration amplitude under the fixed range.

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An experimental investigation was undertaken to determine the ability of Synthetic Jet Actuators to control the aerodynamic properties of a wing. The Synthetic Jet Actuator (SJA) was placed at two separate positions on a wing comprised of a NACA0015 airfoil. The first of the jet positions is located at 12% of the chord, hereby referred to as the leading edge Synthetic Jet Actuator. The second exit position is located at 99% chord of an airfoil and hereby is referred to as the trailing edge Synthetic Jet Actuator. The two locations produced different benefits as the angle of attack of the wing was increased. The leading edge Synthetic Jet Actuator delayed the onset of stall of an airfoil, suppressing stall up to 25 degrees angle of attack. The control of the aerodynamic characteristics was achieved by influencing the amount of the separated flowfield region. The effects of the dynamic stall vortex were investigated with wind tunnel testing during the pitching motion of an airfoil to determine how the flow reacts dynamically. The trailing edge synthetic jet actuator was investigated as a form of low angle “hingeless” control. The study investigated the effect of the jet momentum coefficient on the ability of the synthetic jet to modify the lifting and pitching moment produced from the wind tunnel model. The data indicates that, with the present implementation, the SJA-jet flap generates moderate lift and moment coefficient increments that should be suitable for hinge- less control. It was also shown that, for the current experimental setup and a given jet momentum coefficient, continuous blowing is more effective than oscillatory blowing/sucking. The data shows that combining the SJA with a Gurney flap does not result in performance enhancement.

<p>The purpose of air distribution systems for HVAC is tocreate proper air quality and thermal conditions in an occupiedzone. In mixing type air distribution systems air is suppliedinto a room through various types of outlets and distributed byturbulent air jets. These air jets are the primary factorsaffecting room air motion. The ASHRAE handbook recognises fourmajor zones of maximum velocity decay along a jet.</p><p>Although numerous theoretical and experimental studies havebeen conducted to develop turbulent air jet theory from the1930's, air jet performance in the further field from theoutlet is still not well understood.</p><p>Many studies were therefore carried out, and the followingconclusions can be drawn from them:</p><p>    The end centerline velocities of zone 3 for both "free"jet and wall jet could strongly depend on the outletvelocities and room size.</p><p>    The<i>K</i>-value of wall jets could be a function of bothoutlet velocities and outlet size.</p><p>    It is very important to choose suitable sampling time toevaluate jet performance.</p><p>    CFD can not always be used to predict jet behaviour,especially for the jet with low outlet velocity and in thearea far away from the outlet. However, for a two-dimensionwall jet, CFD could be a powerful tool for designers.</p><p><b>KEYWORDS</b>: air jet, centerline velocity,<i>K</i>-velocity, air diffuser, ventilation, measurement,CFD</p>

Reproduction de : Thèse de doctorat : Océanographie physique : Toulouse 3 : 2007. / Titre provenant de l'écran-titre. Bibliogr. p. 219-230.

Thesis (Ph. D.)--Drexel University, 2004. / Includes abstract and vita. Includes bibliographical references (leaves 156-159).

Thesis (M.S.) in Chemical Engineering--University of Maine, 2001. / Includes vita. Includes bibliographical references (leaves 100-103).