The Use of Electrochemical Techniques to Study Turbulence Close to a Wall

Electrochemical techniques can be used to measure the time averaged velocity gradient and the two components of the fluctuating velocity gradient at a solid surface. A chemical reaction Is carried out at the surface of a small electrode embedded in the wall. The voltage applied to the electrode Is large enough that the current flowing in the circuit is controlled by the mass transfer rate. The probes are the mass transfer analog of the hot wire or hot film anemometer. If the test electrode is part of a large electrode surface, it can be used to measure local time averaged and fluctuating mass transfer rates. Research work on the development of these techniques is reviewed. This includes problems encountered, probe design and mathematical analysis. A typical flow system in which the techniques have been used Is discussed. Data that have been obtained for turbulence close to a wall are presented. A comparison between electrochemical techniques and the thermal wall meters is given

Recent Developments of Electrochemical Wall Mass Transfer Probes and Their Application to Drag-Reducing Polymers

Electrochemical mass transfer probes are used to measure the velocity gradient at a wall. Recent advances in their application are reviewed. These include corrections for the time response of the probe, the simultaneous measurement at a number of locations of the two components of the fluctuating velocity gradient and a study of the influence of drag reducing polymers on turbulence. It is found that drag-reducing polymers cause an increase in the scale of flow oriented eddies in the viscous sublayer

Emotional response to images of wind turbines: a psychophysiological study of their visual impact on the landscape

YesSocial acceptance for wind turbines is variable, providing a challenge to the implementation of this energy source. Psychological research could contribute to the science of climate change. Here we focus on the emotional responses to the visual impact of wind turbines on the landscape, a factor which dominates attitudes towards this technology. Participants in the laboratory viewed images of turbines and other constructions (churches, pylons and power-plants) against rural scenes, and provided psychophysiological and self-report measures of their emotional reactions. We hypothesised that the emotional response to wind turbines would be more negative and intense than to control objects, and that this difference would be accentuated for turbine opponents. As predicted, the psychophysiological response to turbines was stronger than the response to churches, but did not differ from that of other industrial constructions. In contrast with predictions, turbines were rated as less aversive and more calming compared with other industrial constructions, and equivalent to churches. Supporters and non-supporters did not differ significantly from each other. We discuss how a methodology using photo manipulations and emotional self-assessments can help estimate the emotional reaction to the visual impact on the landscape at the planning stage for new wind turbine applications.This work was partly funded by an ESRC First Grant RES-061-25-0512 to D

FEDSM2003-45371 A STOCHASTIC REPRESENTATION OF PARTICLE BEHAVIOR IN GAS-LIQUID HORIZONTAL ANNULAR FLOW

ABSTRACT A stochastic method which uses a modified Langevin equation to represent the velocities of the fluid seen by a particle in a turbulent field is explored. Calculations of the dispersion of particles from a source on a wall agree with calculations at Re τ = 150 which use a DNS to represent the fluid velocity field. The paper demonstrates how wall source calculations can be used to analyze problems involving atomization and deposition, which are of interest in horizontal gas-liquid annular flows. INTRODUCTION A critical issue in developing a model for annular gasliquid flow in a horizontal system is the prediction of the effect of gravity on the spatial distribution of droplets, on the deposition constant and on the droplet turbulence. This paper presents the results of numerical experiments aimed at studying these phenomena. Because of gravity the liquid film on the wall has a nonuniform distribution. Droplets are torn from the film and undergo trajectories which depend on gravity and on the fluid turbulence. Eventually, they deposit on the wall. The drop concentrations are approximately constant in planes perpendicular to the gravity vector. They decrease in the vertical direction because of the effect of gravity. The local deposition rate depends on local concentration at the wall and on the local deposition constant. A discussion of the modeling of entrainment in a horizontal annular flow has been presented by Pan and Hanratty [1]. Baik and Hanratty [2] have recently explored a mechanism for the transition to annular flow in large diameter pipes which considers whether droplet mixing is sufficient to form a film on the top of the pipe. The results of this study are used to address theoretical issues raised in these papers. The simplified system that is considered is a horizontal channel for which droplets enter the field from the bottom wall. Most of them eventually deposit on the bottom wall. A smalle

Real Time Radiation Monitoring Using Nanotechnology

System and method for monitoring receipt and estimating flux value, in real time, of incident radiation, using two or more nanostructures (NSs) and associated terminals to provide closed electrical paths and to measure one or more electrical property change values .DELTA.EPV, associated with irradiated NSs, during a sequence of irradiation time intervals. Effects of irradiation, without healing and with healing, of the NSs, are separately modeled for first order and second order healing. Change values.DELTA.EPV are related to flux, to cumulative dose received by NSs, and to radiation and healing effectivity parameters and/or.mu., associated with the NS material and to the flux. Flux and/or dose are estimated in real time, based on EPV change values, using measured .DELTA.EPV values. Threshold dose for specified changes of biological origin (usually undesired) can be estimated. Effects of time-dependent radiation flux are analyzed in pre-healing and healing regimes