A Networked Two-Dimensional Sonic Anemometer System for the Measurement of Air Velocity in Greenhouses

1999 ◽  
Vol 73 (2) ◽  
pp. 189-197 ◽  
Author(s):  
S. Wang ◽  
M. Yernaux ◽  
J. Deltour
Keyword(s):  
Sonic Anemometer ◽  
Two Dimensional ◽  
Air Velocity ◽  
Anemometer System

A Two-Dimensional Model of a Double-Façade With Integrated Photovoltaic Panels

2005 ◽  
Vol 128 (2) ◽  
pp. 160-167 ◽  
Author(s):  
R. Charron ◽  
A. K. Athienitis
Keyword(s):  
Control Volume ◽  
Cost Effective ◽  
Two Dimensional ◽  
Transfer Coefficients ◽  
Air Velocity ◽  
Heat Transfer Coefficients ◽  
Pv Systems ◽  
Air Temperatures ◽  
Building Integrated Photovoltaic ◽  
Convective Heat Transfer Coefficients

Building integrated photovoltaic (PV) systems that include heat capture are more cost effective than PV systems that generate only electricity. This paper presents a two-dimensional control-volume model for a double-façade with integrated PV. The model may be employed to determine maximum PV temperature. Good agreement with a one-dimensional analytical model is obtained for air temperature rise. Experiments in Montreal showed that air temperatures could increase by 20°C when passing air through a 1m high façade section, and maximum PV temperatures of close to 50°C could be reached even in −17°C weather for an air velocity of 0.6m∕s. The highest uncertainty in PV temperature prediction is due to the values of convective heat transfer coefficients from the literature which are generally lower than observed values.

scholarly journals Raindrop fall velocity in turbulent flow: an observational study

2021 ◽  
Vol 18 ◽  
pp. 33-39
Author(s):  
Merhala Thurai ◽  
Viswanathan Bringi ◽  
Patrick Gatlin ◽  
Mathew Wingo
Keyword(s):  
Turbulent Flow ◽  
Gold Standard ◽  
Sonic Anemometer ◽  
Terminal Velocity ◽  
Laboratory Measurements ◽  
Air Velocity ◽  
Fall Velocity ◽  
Velocity Fluctuations ◽  
The Mean ◽  
Rain Events

Abstract. Laboratory measurements of drop fall speeds by Gunn–Kinzer under still air conditions with pressure corrections of Beard are accepted as the “gold standard”. We present measured fall speeds of 2 and 3 mm raindrops falling in turbulent flow with 2D-video disdrometer (2DVD) and simultaneous measurements of wind velocity fluctuations using a 3D-sonic anemometer. The findings based on six rain events are, (i) the mean fall speed decreases (from the Gunn–Kinzer terminal velocity) with increasing turbulent intensity, and (ii) the standard deviation increases with increase in the rms of the air velocity fluctuations. These findings are compared with other observations reported in the literature.

On 2D Liquid Sheet Atomization

2006 ◽  
Author(s):  
Frederic Couderc ◽  
Jean-Luc Estivalezes
Keyword(s):  
Boundary Layer ◽  
Physical Phenomenon ◽  
Experimental Studies ◽  
Maximum Amplitude ◽  
Liquid Sheet ◽  
Linear Stability Theory ◽  
Complete Agreement ◽  
Two Dimensional ◽  
Air Velocity ◽  
Global Oscillation

Liquid sheet atomization by coflowing air flows appears in a broade range of industrial process, but still remains not well understood. This paper is devoted to the numerical investigation of the air-assisted disintegration of a planar liquid sheet by two parallel air streams flowing on both sides. To do that, a DNS solver for two-phase incompressible viscous flows with interface capturing feature for non miscible fluids has been developped and validated [1]. The interface is captured by a Level-Set method, which has become very popular during the last ten years. However, unlike classical approaches, stress tensor jump conditions across the interface are explicitly taken into account without introducing any smoothing. Although the physical phenomenon is tridimensional, experimental studies show that the initial stage of the liquid sheet oscillations is mainly two-dimensional which justifies the two dimensional simulations done in this paper. We present a first two-dimensional spatial simulation which shows the gas flow dynamics in interaction with the liquid sheet oscillations. By separation of the air boundary layer behind the liquid sheet at its maximum amplitude location, vortical structures are created and evolve in time with the frequency of the liquid sheet global oscillation. We investigate the effects of the main flow parameters such as outer air velocity, air boundary layer thickness on the main characteristics of the flow and the global oscillation frequency. The first result from our study concerning the frequency oscillation shows a linear variation of the frequency with air velocity. This is in complete agreement with experimental results of [2], whereas inviscid linear stability theory predicts a quadratic evolution. Evidence from those results shows that two-dimensional spatial simulations can provided relevant information on the early stage of liquid sheet atomization.

Meramal Aliran Udara dan Keselesaan di dalam Masjid Sultan Salahuddin Abdul Aziz Shah Menggunakan Simulasi Komputer

2014 ◽  
Vol 69 (1) ◽  
Author(s):  
Shamsul Sarip ◽  
Mat Nawi Wan Hassan
Keyword(s):  
Temperature Distribution ◽  
Flow Direction ◽  
Ventilation System ◽  
Computer Software ◽  
Comfort Level ◽  
Two Dimensional ◽  
Air Velocity ◽  
Temperature Distributions ◽  
Air Supply ◽  
Consumer Dissatisfaction

A study on ventilation system using a two dimensional turbulence k-e model with the assumption that the fluid is incompressible and non-isothermal is presented. The purpose of this study is to predict the distribution of air velocity and temperature in main hall Masjid Sultan Salahuddin Abdul Aziz Shah in Shah Alam.  When the airflow and temperature distribution have been predicted by the computer software FLUENT, the comfort level can easily be determined. Nine cases have been conducted to examine the effects of input air velocity, air velocity from the fan heli and fan air flow direction to the percentage of consumer dissatisfaction. Mixing characteristics of comfort have been analyzed under different air supply velocities, temperatures and fan velocities. The fan velocity directions involved two conditions which are the upwards and downwards directions. The results from the research in the form of air velocity and temperature distributions are important in determining the comfort level which is unsuitable for the user. It was found that cases of 3,4, 5, 6 and 7 show the effect of a very good comfort with the percentage of PPD between 10% to 20%. The location of heli fans also affects the impression of comfort in the main hall. The comfort level of this area can be improved by modifying the position and increasing the number of fans in the hall.

The correction of hot-wire readings for proximity to a solid boundary

1962 ◽  
Vol 12 (3) ◽  
pp. 388-396 ◽  
Author(s):  
J. A. B. Wills
Keyword(s):  
Velocity Profile ◽  
Heat Loss ◽  
Turbulent Flows ◽  
Solid Boundary ◽  
Two Dimensional ◽  
Hot Wire ◽  
Velocity Measurements ◽  
Air Velocity ◽  
The Wire

When using a hot wire for velocity measurements close to a solid boundary, errors may be introduced if the effect of the boundary on the rate of heat loss from the wire is ignored. An experimental determination of the effect is described, in which a hot wire was mounted at various distances from a metal surface forming one wall of a two-dimensional channel. The rate of heat loss was determined electrically, and the air velocity at the wire found from the known laminar velocity profile. The application of the results to turbulent flows is discussed briefly.

Spectrophotometric measurements of objective-prism spectra

1966 ◽  
Vol 24 ◽  
pp. 118-119
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
Progress Report ◽  
Two Dimensional ◽  
Objective Prism ◽  
Made In

I should like to give you a very condensed progress report on some spectrophotometric measurements of objective-prism spectra made in collaboration with H. Leicher at Bonn. The procedure used is almost completely automatic. The measurements are made with the help of a semi-automatic fully digitized registering microphotometer constructed by Hög-Hamburg. The reductions are carried out with the aid of a number of interconnected programmes written for the computer IBM 7090, beginning with the output of the photometer in the form of punched cards and ending with the printing-out of the final two-dimensional classifications.

Introductory paper

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan
Keyword(s):  
Line Intensity ◽  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Dimensional Array ◽  
Rr Lyrae ◽  
Metallic Line ◽  
Introductory Paper ◽  
Parameter Varying ◽  
Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

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