anemometer Articles
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Orthogonal probe performance from a non-orthogonal sonic anemometer
1. Introduction In the spring of 2014 we conducted an experiment in the backyard of Applied Technologies, Inc. comparing the performance of two of our sonic anemometers, the orthogonal K-Probe and the non-orthogonal A-Probe (Zimmerman et al., 2014). We were responding to concerns in the sonic anemometer user community about the reliability of vertical velocity measurements in the non-orthogonal ...
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Sonic Thermometry
Sonic anemometers have had extensive use in the scientific community. These instruments are used to measure atmospheric parameters that most rotating instruments cannot. Wind speed and wind direction or individual axes of wind velocity are most commonly measured. Along with these measurements, another parameter can be extracted from the sonic anemometer (i.e.), sonic temperature. Since the ...
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Effects of averaging time on predicted gas concentrations
The potential consequences of a particular gaseous emission usually relate to a specific averaging time. However, the averaging time associated with gas monitoring data in the region of a discharge may differ from the averaging time implicit in a model employed to predict the concentration resulting from that emission. Tables of factors exist for taking account of such differences and recent ...
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Mechanical vs. Ultrasonic Anemometers for Wind Turbine Control
What do you think? Does the replacement of mechanical wind sensors trough ultrasonic anemometers in wind turbine control pay off after less than a few years? Free Cost Benefit Analysis about Replacement of Mechanical Wind Sensors Anemometers are vital components of utility-scale wind turbines and determine the performance of the turbine’s output. In the market today, companies are ...
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The origin and type of wind speed sensor
backgroundAn anemometer is an instrument used to measure wind speed and direction. It is a critical tool for meteorologists, engineers, and researchers who need to gather information about atmospheric conditions. Anemometers come in various types, but they all work based on the same principle of detecting the wind's pressure and translating it into a measurable quantity. In this article, we will ...
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Minimizing flow distortion errors in a sonic anemometer
This paper describes a simple approach to minimizing probe-induced flow distortion errors in a three-axis sonic anemometer. By separating the three axes, mutual interference between the transducers and supports in the three arrays is reduced. Only a transducer shadow correction determined from wind tunnel tests is needed to obtain measurements that are virtually insensitive to probe orientation ...
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Wind101A – Wind Units Set-Up and Troubleshooting
The Wind101A comes programmed with an engineering unit to provide the average wind speed using a 10 second reading rate. If a different reading interval is desired, a different engineering unit must be created to properly scale pulses to wind speed. Note: these instructions assume that the Comptus anemometer from the Wind101A kit is being used. If it is any other sensor, the instructions for ...
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Weather measurement in extreme conditions - Whistler Mountain - Case Study
Whistler Blackcomb mountain is a premiere winter resort in British Columbia Canada. Some months ago our subsidiary "LufftUSA" installed the first Ventus-UMB ultrasonic anemometer atop a main ski lift on the Whistler mountain. The first winter storm passed leaving the entire mountain and all mechanical equipment covered in snow and ice... except the Ventus-UMB. The Ventus-UMB continued to give ...
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Flow-distortion errors in a non-orthogonal sonic anemometer
Part 1 - UNDERSTANDING NON-ORTHOGONAL SONIC ANEMOMETERS Non-orthogonal sonic anemometers have been around for about twenty years. We define them as having three measurement axes inclined at an angle of 60 deg to the horizontal and intersecting at their midpoints to form a small sampling volume. The open aspect of the array was immediately appealing to users. There are several makes on the market ...
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Orthogonal and non-orthogonal sonic anemometers compared
1. Introduction The performance of non-orthogonal sonic anemometers has been the subject of much discussion in recent years. It followed findings that they underestimated vertical winds and vertical heat fluxes by 10-15%. For agricultural and forestry scientists who depended on them for their large-scale energy balance studies this was a bad surprise. They had collected turbulence data from ...
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Verification of wind energy related measurements with a SODAR system
Abstract Complex terrain and growing wind energy converters (WEC) in wind parks generate increasing interest in determining wind profiles and turbulence besides the general forecast of annual energy production. Increasing hub heights and growing rotor diameters of advanced WEC make SODAR systems a valuable alternative to meteorological towers. SODAR systems provide wind profiles as well as ...
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Another look at sonic thermometry
Abstract. In this note we reassess the role of sonic thermometry in boundary-layer studies. The sonic temperature signal, when corrected for crosswind velocity contamination, very closely approximates the virtual temperature of air. This variable is needed for many boundary-layer calculations. We describe preliminary tests with a new sonic anemometer-thermometer that performs the velocity ...
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Why Does the Non-Orthogonal Sonic Anemometer Underestimate
The performance of non-orthogonal sonic anemometers has been the subject of much discussion in recent years. It followed findings that they underestimated vertical winds and vertical heat fluxes by 10-15%. For agricultural and forestry scientists who depended on them for their large-scale energy balance studies this was a bad surprise. They had collected turbulence data from hundreds of ...
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Basic tests for checking validity of field data
The following guidelines are suggested for verifying micrometeorological data gathered in field experiments. It is assumed, for simplicity, that the observations being tested are made over open, relatively flat and uniform terrain, with small roughness elements. It is also assumed that the sensors and the data acquisition and recording hardware are basically sound and that the purpose of the ...
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Some thoughts on in-situ flux measurement in the atmospheric surface layer
Due to its complexity, the state of a turbulent atmosphere can only be described using statistical quantities such as means, variances, and covariances. Computation of these statistical quantities, particularly those of higher order, must be done with considerable care. This is particularly true if the statistics are used to depict heat and momentum fluxes. This note contains considerations that ...
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Understanding non-orthogonal sonic anemometers
Non-orthogonal sonic anemometers have been around for about twenty years. We define them as having three measurement axes inclined at an angle of 60 deg to the horizontal and intersecting at their midpoints to form a small sampling volume. The open aspect of the array was immediately appealing to users. There are several makes on the market and each solved the problem of holding the transducers ...
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Sonic temperature significance and limitations
The ATI sonic thermometer measures temperature from transit times t1 and t2 measured along the vertical path of the anemometer's probe. They are the times taken by sound pulses to traverse the 15-cm acoustic path in opposite directions; (these same transit times are used also for computing the vertical wind component). The instrument exploits the strong dependence that exists between the speed ...
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Fluoride Emission from Anode Butts in a Cooling Tunnel
Abstract Nordic Aluminium has been trying out a cooling tunnel for hot anode butts in order to lower the fluoride content of the working environment. The cooling tunnel is connected to the Fume Treatment Plant so that it has forced suction from it. The purpose of this study is to evaluate the effectiveness of the tunnel in removing HF emissions and make suggestions on how to make the tunnel ...
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Do you need to measure air flow?
Look no further. This hot wire thermo-anemometer is ideal for low air velocity, volume, and temperature measurement. If your desired application involves ventilation surveying, the maintenance of air conditioning systems, or environmental monitoring, this product will meet your requirements and more. Record your measurements on a slim plug-in telescopic probe and download the data in real-time ...
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High-resolution wind-tunnel datasets from the University of Hamburg: validation of street canyon dispersion models
Air quality is one of the major environmental concerns in cities as it has a direct impact on human health. One of the biggest sources of air pollution is urban traffic. To predict air quality in urban areas, significant effort and considerable funding has been, and is being, spent in developing numerical models for urban dispersion and in obtaining experimental datasets. So far, less effort has ...
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