2,073 results
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2. Three Dimentional Anemometer Using Thin Film Temperature Elements
- Author
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Matsumoto, Takafumi, Guo, Xiaolin, Matsui, Hirohito, Ozaki, Yukikatsu, Kamiya, Yasutaka, Kondo, Koji, Miyano, Hirotaka, China Society of Automotive Engineers, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, and Zhang, Junjie James, Series Editor
- Published
- 2021
- Full Text
- View/download PDF
3. Graphite on paper as material for sensitive thermoresistive sensors
- Author
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Nam-Trung Nguyen, Hoang-Phuong Phan, Toan Dinh, Dzung Viet Dao, Peter Woodfield, and Afzaal Qamar
- Subjects
Materials science ,business.industry ,Analytical chemistry ,Thermionic emission ,General Chemistry ,Highly sensitive ,Thermal sensing ,Anemometer ,Materials Chemistry ,Rectangular potential barrier ,Optoelectronics ,Graphite ,business ,Temperature coefficient - Abstract
This paper reports on the thermoresistive properties of graphite on paper (GOP). A negative temperature coefficient of resistance (TCR) from −2900 to −4400 ppm K−1 was observed for the GOP. This negative and large TCR is attributed to an increase in the thermionic emission current over a low potential barrier with increasing temperature. The potential barrier was found to be 33 meV between the graphite grains. The paper also demonstrates the use of the GOP in a highly sensitive (0.83 mV (m s−1)−0.8 mW−1) GOP-based anemometer, indicating strong feasibility of using this material for low-cost and sensitive thermal sensing applications.
- Published
- 2015
4. Wind speed measurement by paper anemometer
- Author
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Juhua Zhong, Wenchuan Guan, and Zhongqi Cheng
- Subjects
Physics ,geography ,geography.geographical_feature_category ,Microphone ,Acoustics ,General Physics and Astronomy ,STRIPS ,Wind speed ,Education ,law.invention ,Standing wave ,Noise ,Amplitude ,law ,Anemometer ,Sound (geography) - Abstract
A simple wind speed measurement device, a paper anemometer, is fabricated based on the theory of standing waves. In providing the working profile of the paper anemometer, an experimental device is established, which consists of an anemometer sensor, a sound sensor, a microphone, paper strips, a paper cup, and sonic acquisition software. It shows that the sound wave detected in the paper cup has a larger amplitude and the noise is depressed, though the frequency of the sound is twice that detected directly from the strip. From the experiments, we find that the frequency of the sonic wave does not change with wind speed; however, its amplitude increases with wind speed. To predict the wind speed, a correlation is established from the sound wave amplitude.
- Published
- 2011
5. SC4-1: Spray Behavior near the Nozzle of a DISI Multi-Hole Injector Using Phase Doppler Anemometer(SC: Spray and Spray Combustion,General Session Papers)
- Author
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Mamoru Sumida, Eiji Tomita, Fatma B.M. Ahmed, and Nobuyuki Kawahara
- Subjects
Engineering ,law ,business.industry ,Anemometer ,Nozzle ,Injector ,Session (computer science) ,Aerospace engineering ,Combustion ,business ,Phase doppler ,Automotive engineering ,law.invention - Published
- 2008
6. Hot-wire anemometer paper tape reader
- Author
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John H. Jory
- Subjects
Engineering ,Reliability (semiconductor) ,business.industry ,Paper tape ,Anemometer ,Reading (computer) ,Computation ,Acoustics ,Airflow ,Electrical engineering ,Transient (oscillation) ,business ,Gas compressor - Abstract
The Hot-Wire Anemometer Paper Tape Reader was conceived as a relatively simple apparatus to serve as a high reliability device such as required in peripheral computation equipment. The hot-wire anemometer principle has been employed extensively in the past for the study of transient air flow phenomena in compressors and turbines. The principle of operation concerns an electrically heated wire used to detect a change in air velocity in its immediate vicinity by observing its change in temperature and consequent change in resistance. Using this principle to read perforated members such as punched paper tape at high speeds offers a number of distinct advantages over conventional reading methods.
- Published
- 1960
7. Paper 9: Velocity and Rate of Flow Measurements in Internal Combustion Engines
- Author
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M. J. Tindal, T. J. Williams, and L. J. Kastner
- Subjects
Embryology ,Engineering ,Field (physics) ,business.industry ,Flow (psychology) ,Mechanical engineering ,Reciprocating engine ,Cell Biology ,Combustion ,Pressure sensor ,Anemometer ,Metering mode ,Anatomy ,Constant (mathematics) ,business ,Developmental Biology - Abstract
Measurement of both the mean and instantaneous values of gas velocity in internal combustion (i.c.) engines presents problems of considerable difficulty and the application of electronic methods of measurement has made important contributions in this field. The problems encountered in metering pulsating flows are briefly discussed with special reference to the advantages of two metering devices which employ electronic circuits. Whilst pressure transducers enable the variation in instantaneous gas velocities to be inferred in certain circumstances there are many other cases where a direct indication of velocity variation is desirable. The hot wire anemometer (h.w.a.) has been highly developed for aeronautical engineering applications but special problems arise in the reciprocating engine where velocity variations can be large. This paper describes a constant temperature h.w.a. using a d.c. circuit which has proved stable and relatively easy to operate. If velocity measurements in the engine cylinder are required the problem becomes a three-dimensional one, and the response of the h.w.a. to variation in flow direction is discussed. Consideration is given to materials suitable for probe wires.
- Published
- 1965
8. Paper 9: The Measurement of Turbulent Velocity Fluctuations and Turbulent Temperature Fluctuations in the Supercritical Region by a Hot Wire Anemometer and a ‘Cold’ Wire Resistance Thermometer
- Author
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W. H. Denton, L. E. Gill, P. J. Bourke, and D. J. Pulling
- Subjects
Embryology ,Chemistry ,Turbulence ,Thermodynamics ,Cell Biology ,Mechanics ,Supercritical fluid ,Anemometer ,Thermometer ,Turbulent velocity ,Anatomy ,Experimental methods ,Wire resistance ,Developmental Biology - Abstract
It is necessary to develop experimental methods for measuring the local turbulent velocity and turbulent temperature fluctuations in the supercritical region in order to investigate the unusual heat transfer phenomena that occur in heating turbulent flows of fluids in this region. The performance of the constant temperature hot wire anemometer has been investigated in isothermal turbulent flow of carbon dioxide in a pipe at supercritical pressures from 1075 to 1200 lb/in2 ( Pc = 1071 lb/in2) and at temperatures from 24·5 to 40°C ( Tc = 31°C), including the critical range of rapid variation in physical properties in which the fluid changes from liquid to gas. The wire temperature was varied and linear mean velocity calibrations were obtained which were found to be markedly sensitive to the pressure, the fluid bulk temperature, and the wire temperature. Measurements of turbulent velocity fluctuations agreed with the expected values for this isothermal case. The heat transfer from the wire showed no unusual characteristics and was correlated for variation in pressure, fluid bulk temperature, and wire temperature by using mean values of the physical properties over the wire to bulk temperature range. Because of the sensitivity of the wire calibrations to temperature, measurement of the local fluid temperature is required to allow velocities to be measured in the presence of temperature gradients in the supercritical region. A probe has therefore been developed with a thin cold wire resistance thermometer, mounted close to a pair of crossed hot wires and with a sufficiently fast thermal response for the measurement of temperature fluctuations as well as mean temperature. Experiments are described with this probe in the presence of temperature gradients in turbulent flow, but so far only in air. Simultaneous measurements were made of both the radial velocity fluctuations and temperature fluctuations in a volume of air that was small compared with the scale of turbulence. The time-correlation of these two quantities was found to be strong near the wall of the tube and to fall to zero towards the centre. Further, the local radial turbulen theat flux calculated from the mean product of these two quantities agreed quantitatively with the known heat flux for various radial positions in the tube. The remaining problem is to investigate the effects that temperature fluctuations in the supercritical region have upon the measurement of velocity fluctuations and on the local values of the density and specific heat.
- Published
- 1967
9. A PAPER ANEMOMETER
- Author
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P. G. Hookey
- Subjects
Atmospheric Science ,Anemometer ,Acoustics ,Environmental science - Published
- 1965
10. Paper 36: Wake—Boundary Layer Interaction in Tandem Cascades
- Author
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M. J. Moore, J. W. Railly, and S. D. Deeb
- Subjects
Physics ,Embryology ,Suction ,Tandem ,Cell Biology ,Mechanics ,Wake ,Adverse pressure gradient ,Boundary layer ,Anemometer ,Cascade ,Wall suction ,Anatomy ,Developmental Biology - Abstract
The performance of a tandem cascade in a cascade wind-tunnel is discussed and the characteristics of a given cascade are presented ( a) without end wall suction and ( b) with suction, in order to produce two-dimensionality as closely as possible. Necessary criteria for the existence of two-dimensional conditions are stated. A discussion is given of the development of the boundary layer on the second blade as affected by the wake based on hot wire anemometer investigations. In addition, a separate experiment is described in which a wake is allowed to impinge on a flat plate, subject to an adverse pressure gradient. From both experiments the influence of the size of slot between the tandem aerofoils is assessed.
- Published
- 1969
11. Аналіз методів визначення тривалості сушіння соснових необрізних пиломатеріалів
- Author
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Yuriy Huber, Yuriy Dadak, Zhanna Humeniuk, and Zoya Kopynets
- Subjects
параметри режиму сушіння ,температура агента сушіння ,відносна вологість ,швидкість руху агента сушіння через штабель ,конвективна сушильна камера періодичної дії ,Drying time ,Stack (abstract data type) ,Volume (thermodynamics) ,Kiln ,Anemometer ,lcsh:SD1-669.5 ,Relative humidity ,Stage (hydrology) ,lcsh:Forestry ,Pulp and paper industry ,Water content ,Mathematics - Abstract
A convective method to dry lumber is the most common in batch kilns. To ensure the implementation of the production plan, it is important to determine the required number of drying chambers, and in the calculation of their productivity, the duration of the drying process is taken into account. This is the main stage both for planning the work of existing drying shops and for designing new woodworking enterprises, their expansion or reconstruction. According to the results of experimental drying processes carried out under production conditions in a LeKo convective drying batch kiln of the LK-ZDR-50 type with a loading volume of about 50 m3 of lumber, determined was the drying time for the multi-stage schedule of drying unedged pine lumber with a thickness of 30 mm and a length of 3...3.2 m. During the experimental studies, the initial moisture content of the lumber was %, the final – %. The temperature of the drying agent (moist air) at the first stage of the drying schedule was °C, the relative humidity of the drying agent – %; at the last stage – °С, %. The circulation scheme of the drying agent in the chamber is transverse-vertical, the average speed of the drying agent movement through the stack, measured using a vane anemometer with a Testo 416 telescopic probe, for moisture content of the lumber being dried is more than 31% – m/s, with moisture content less than 31% – m/s. The average time of the study drying processes is h. For the purpose of analysis, eleven calculation methods for determining the duration of lumber drying process were selected, namely: tabular, which is recommended by the “Guiding technical materials on the chamber drying technology of sawn timber” and its two variants with certain refinements, tabular by Yo.V. Andrashek, tabular by L. Glijer, graphoanalytical by P.S. Sergovsky, graphoanalytical by E.A. Mikit, analytical by F. Kollmann, analytical by William T. Simpson, analytical according to T. Trubswetter, analytical by L. Vorreiter. Comparing the calculations results of the time for drying with experimental data, it was found that for unedged pine lumber in modern convective drying batch kilns, the following methods can be recommended: graphoanalytical by P.S. Sergovsky – the deviation is 2.32%, analytical by William T. Simpson – the deviation is 7.25%, and analytical by L. Vorreiter – the deviation is 2.46%. It was found that in order to obtain results that are sufficiently accurate under production conditions, the correction coefficient, which depends on the wood species, initial moisture content, chamber structure, and relative humidity of the drying agent using the F. Kollmann method, should be for given research conditions When changing the factors on which it depends, the calculation results by this method can significantly differ from experimental data. It was found that the method applied according to T. Trubswetter will have sufficient accuracy for production conditions (deviation will be 7.82%), subject to the amendments proposed in this paper.
- Published
- 2020
12. Measurement of motion corrected wind velocity using an aerostat lofted sonic anemometer.
- Author
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Stevens, W. R., Squier, W., Mitchell, W., Gullett, B. K., and Pressley, C.
- Subjects
WIND speed measurement ,ANEMOMETER ,ACOUSTICAL engineering equipment ,ALTITUDES ,GLOBAL Positioning System ,AIRSHIPS - Abstract
An aerostat-lofted, sonic anemometer was used to determine instantaneous 3 dimensional wind velocities at altitudes relevant to fire plume dispersion modeling. An integrated GPS, inertial measurement unit, and attitude heading and reference system cor rected the wind data for the rotational and translational motion of the anemometer and rotated wind vectors to a global North, West, Up coordinate system. Data were taken at rates of 10 and 20 Hz to adequately correct for motion of the aerostat. The method was applied during a prescribed forest burn. These data were averaged over 15 min intervals and used as inputs for subsequent dispersion modeling. The anemometer's orientation data are demonstrated to be robust for converting the wind vector from the internal anemometer reference system to the global reference system with an average bias between 5 and 7°. Lofted wind data are compared with sonic anemometer data acquired at 10m on a mast located near the tether point of the aerostat and with local meteorological data. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
13. 2. Abstract of a Paper on Results of Observations made with Whewell's New Anemometer
- Author
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John Ranken
- Subjects
Meteorology ,Anemometer ,General Engineering ,Environmental science ,Remote sensing - Abstract
In laying the results of these observations before the Society, it was thought necessary to make a few remarks in explanation of the manner in which they were made.The instrument consists of a fixed japanned cylinder, on which the points of the compass are marked, and a moveable portion, which revolves freely round the cylinder as the wind changes; the circular disk of a fly kept opposite to the wind by a weathercock vane, is made to revolve with a velocity proportional to that of the wind. The motion thus produced is diminished by means of endless screws, working in a pair of toothed-wheels, and carried down to a pencil, which, in its descent, rubs on the surface of the cylinder, and traces a broad line, whose length is proportional to the velocity of the wind, and the time during which it blows from any one direction taken jointly. The compartment of the cylinder on which the marks are made indicates the direction of the wind.
- Published
- 1844
14. El diseño de un modelo lineal de comportamiento para un anemómetro análogo comparando los métodos de mínimos cuadrados y de interpretación línea de Newton por diferencias divididas.
- Author
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Vargas Oseguera, L. L., Rodríguez-González, J. M., Morán-Hernández, J., and Terán-Soria, A.
- Subjects
- *
WIND speed measurement , *NEWTON-Raphson method , *LEAST squares , *WIND tunnels , *WIND power - Abstract
This article underscores the importance of accurate wind speed measurements and highlights the necessity of standardizing anemometers using robust mathematical models to ensure reliable data across a range of fields, including meteorology, wind energy, aviation, and civil engineering. Two classical mathematical modeling methods--the Least Squares Method and Newton's Divided Differences Method--are presented and compared. The paper evaluates the performance of these methods in anemometer standardization, taking into account their practical applications, limitations, and accuracy under varying experimental conditions. Previous studies demonstrating the efficacy of both methods across different domains are referenced. A methodology is proposed for comparing the two approaches through a controlled wind tunnel experiment using a calibrated digital anemometer under diverse flow conditions. The results will enable researchers and practitioners to select the most appropriate method for their specific needs, thereby enhancing the precision and reliability of wind speed measurements in a wide array of applications. In conclusion, the paper aims to provide a comprehensive analysis of the advantages and limitations of the Least Squares Method and Newton's Divided Differences Method in anemometer standardization, ultimately contributing to improved measurement quality in various sectors. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
15. Note on the application of planar-fit rotation for non-omnidirectional sonic anemometers.
- Author
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Li, M., Babel, W., Tanaka, K., and Foken, T.
- Subjects
PLANAR transistors ,EDDY current testing ,ANEMOMETER ,OMNIRANGE system ,MEASUREMENT ,ELECTRIC distortion - Abstract
The article discusses the study which develops the planar-fit method to allow the usage of the eddy-covariance technique in a landsape with a non-uniform wind field and align the sonic anemometer with the wind fields. It says that the planar-fit method is suited for omnidirectional sonic anemometers. It mentions the disturbed and undisturbed measuring sector of the non-omnidirectional sonic anemometer with no distortion flow.
- Published
- 2012
- Full Text
- View/download PDF
16. Evaluation of turbulent dissipation rate retrievals from Doppler cloud radar.
- Author
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Shupe, M. D., Brooks, I. M., and Canut, G.
- Subjects
ATMOSPHERIC models ,TURBULENCE ,DOPPLER radar ,ANEMOMETER ,SIMULATION methods & models - Abstract
The article presents a study which looks into turbulent dissipation rate retrievals from Doppler cloud radar in Arctic mixed-phase stratocumulus clouds. Using sonic anemometer measurements from research aircraft observations, the study derives the dissipation rate. It also explores capabilities of operational cloud radars.
- Published
- 2012
- Full Text
- View/download PDF
17. Experimental investigation of co-flow jet's airfoil flow control by hot wire anemometer.
- Author
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Bahrami, A., Hoseinzadeh, S., Heyns, P. S., and Mirhosseini, S. M.
- Subjects
AEROFOILS ,JETS (Fluid dynamics) ,WIND tunnels ,BOUNDARY layer (Aerodynamics) ,ANEMOMETER ,DRAG coefficient - Abstract
An experimental flow control technique is given in this paper to study the jet effect on the coflow jet's airfoil with injection and suction and compared with the jet-off condition. The airfoil is CFJ0025-065-196, and the Reynolds number based on the airfoil's chord length is 10
5 . To measure the turbulence components of flow, a hot wire anemometry apparatus in a wind tunnel has been used. In this paper, the effect of the average velocity and boundary layer thickness on the coflow jet's airfoil is analyzed. The test is done for two different coflow velocities and for different angles of attack. It is also shown that, by increasing the velocity difference between the jet and the main flow, separation is delayed, and this delay can be preserved by raising coflow velocity at higher angles of attack. So, this flow control method has a good efficiency, and it is possible to reach higher numbers of lift and lower numbers of drag coefficients. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
18. On the Variation of Cup Anemometer Performance Due to Changes in the Air Density.
- Author
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Alfonso-Corcuera, Daniel, Meseguer-Garrido, Fernando, Torralbo-Gimeno, Ignacio, and Pindado, Santiago
- Subjects
WIND speed measurement ,ANEMOMETER ,DENSITY ,MEASUREMENT errors ,WIND turbines ,PERMANENT magnets - Abstract
In the present paper, the effect of air density variations on cup anemometer performance is analyzed. The effect on the sensor's performance is mainly due to the difference between the altitude at which the cup anemometer is working and the altitude at which this instrument was calibrated. Data from the available literature are thoroughly analyzed, focusing on explaining the coupled effect of the air temperature on both the rotor's friction torque and the air density (that is, related to the aerodynamic torque on the rotor). As a result, the effect of air density variation at constant temperature (that is, leaving aside any variation of friction forces at the anemometer rotor shaft) on the sensor transfer function (i.e., on the calibration constants) is evaluated. The analysis carried out revealed a trend change in the variation with air density of the transfer function of the cup anemometer. For densities greater than 0.65, the calibration constants of the instrument have a variation with density that must necessarily change suddenly as the start-up speed, represented by the calibration constant B, becomes zero around this value of air density. To highlight the relevance of the present research, some estimations of the effect of wind speed measurement errors associated with air density changes on the Annual Energy Production (AEP) of wind turbines are included. A 1.5% decrease in the AEP forecast at air density corresponding to 2917 m above sea level is estimated for 3000–4500 kW wind turbines. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
19. Philip G. Hubbard, Developer of the Hot-Film Anemometer for Measuring Velocity of Turbulent Water Flow.
- Author
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Ettema, Robert
- Subjects
TURBULENT flow ,TURBULENCE ,ANEMOMETER ,VELOCITY ,CIVIL engineering - Abstract
Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
20. Effect of Wind-Induced Vibration on Measurement Range of Microcantiflever Anemometer.
- Author
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Ye, Yizhou, Wan, Shu, and He, Xuefeng
- Subjects
VIBRATION measurements ,ANEMOMETER ,WIND speed ,FLOW sensors - Abstract
In this paper, the effect of wind-induced vibration on measurement range of microcantilever anemometer is investigated for the first time. The microcantilever anemometer is composed of a flexible substrate and a piezoresistor. The wind speed can be detected through the airflow-induced deformation in the flexible substrate. Previous work indicated that the flexible substrate vibrates violently once the wind speed exceeds a critical value, resulting in severe output jitter. This wind-induced vibration limits the measurement range of the anemometer, and the relationship between the anemometer measurement range and its structural parameters has not been explored systematically. Therefore, this paper aims to reveal this relationship theoretically and experimentally, demonstrating that a shorter and thicker cantilever with larger stiffness can effectively suppress the wind-induced vibration, leading to the critical speed rising. By eliminating the wind-induced vibration, the measurement range of the microcantilever anemometer can be increased by up to 697%. These results presented in this paper can pave the way for the design and fabrication of wide-range mechanical anemometers. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
21. Correction of Error of Airborne Anemometers Caused by Self-Excited Air Turbulence.
- Author
-
Liu, Jianqiang, Zhao, Zhan, Fang, Zhen, Li, Yong, and Du, Lidong
- Subjects
WIND speed ,WIND speed measurement ,TURBULENCE ,COMPUTATIONAL fluid dynamics ,SELF-induced vibration ,ANEMOMETER - Abstract
An airborne anemometer, which monitors wind on the basis of Meteorological Multi-rotor UAVs (Unmanned Aerial Vehicles), is important for the prevention of catastrophe. However, its performance will be affected by the self-excited air turbulence generated by UAV rotors. In this paper, for the purpose of the correction of an error, we developed a method for the elimination of the influence of air turbulence on wind speed measurement. The corresponding correction model is obtained according to the CFD (Computational Fluid Dynamics) simulation of a six-rotor UAV which is carried out with the sliding grid method and the S-A turbulence model. Then, the model is applied to the developed prototype by adding the angle of attack compensation model of the airborne anemometer. It is shown by the actual application that the airborne anemometer can maintain the original measurement accuracy at different ascent speeds. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
22. Cross‐wavelet analysis of coherent wind and saltation events.
- Author
-
Ellis, Jean T. and Sherman, Douglas J.
- Subjects
TIME series analysis ,WIND measurement ,WIND speed ,SEDIMENT transport ,ANEMOMETER ,SAND - Abstract
This paper presents high‐resolution field measurements of the wind and saltation fields using miniphones and anemometers located 20–40 mm apart (bed‐parallel) and 10–40 mm above the bed. The average wind speeds at the Shoalhaven Heads, Australia and the Jericoacoara, Brazil field sites are both 4.4 m s−1, and the average saltation rates are 5.0 and 22.2 counts/mm2 s−1, respectively. Normalized cross‐covariance analysis between the wind and saltation time series indicates a dominant saltation response time of 0 s. Cross‐wavelet analysis focusing on short‐duration events characterizes statistically significant wind–sand events and intervals. In the high aeolian saltation rate environment (Brazil), the events and intervals averaged 1.9 and 12.2 s. The low transport environment (Australia) resulted in 2.1 s events and 10.8 s intervals. This study demonstrates that wind–sand events occur about 15% of the time but account for about 23% of the sand transport. These results were possible because of the presentation of a wavelet‐derived event time series. The criticality of tightly controlled field experiments to measure coincident wind and saltation fluctuations with co‐located sensors was demonstrated. This paper emphasizes the importance of the contribution of saltation events to time‐averaged transport rates, which influences sediment flux modelling. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
23. Using sonic anemometer temperature to measure sensible heat flux in strong winds.
- Author
-
Burns, S. P., Horst, T. W., Blanken, P. D., and Monson, R. K.
- Subjects
HEAT flux measurement ,ATMOSPHERIC models ,ANEMOMETER ,THERMOCOUPLES ,SIMULATION methods & models - Abstract
The article presents a study which quantifies the sensible heat flux in strong winds through analyzing data from the Niwot Ridge Subalpine Forest AmeriFlux site (NWT). The study looks into the discrepancy in the calculated sensible heat flux and compares the calculated sensible heat flux and those computed with a co-located thermocouple. It also describes the concepts of energy balance equation and instrumentation.
- Published
- 2012
- Full Text
- View/download PDF
24. Development of Localized 3D-Printed Ultrasonic Wind Anemometer with Cloud Data Transfer and Storage.
- Author
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Pedro, Jewel Leila Mae A. San, Martinez, Dan William C., Gozun, Patrick James P., Reyes, Kyle Andrew C., and Ruiz, Suzaine Joice
- Subjects
ANEMOMETER ,THREE-dimensional printing ,MICROCONTROLLERS ,DATA analysis - Abstract
The core aspects to characterize the wind condition of the environment around us are direction and speed, simply the value of velocity. This encourages the researchers to address the lack of locally fabricated ultrasonic anemometers available in the Philippine market. The study develops a locally fabricated ultrasonic wind anemometer that can measure a wide range of wind speeds and determine its direction. The casing of the anemometer will be manufactured using 3D-printing technology and utilize ultrasonic sensors to achieve accuracy and customizability. In this paper, testing has been conducted to test and validate the capability of the ultrasonic anemometer in which the data gathered from these tests will be used to calibrate the system and design of the ultrasonic wind anemometer. The wind speed and direction measured by the ultrasonic anemometer are collected and employed in the cloud for easy access when the data is needed. The developed ultrasonic wind anemometer with cloud data transfer and storage has been fabricated successfully for wind monitoring and the device could be a stand-alone wind measuring instrument or can be integrated within a weather monitoring system. Improving the wind velocity obtained by the localized ultrasonic wind anemometer using other ultrasonic sensors and exploring different microcontrollers may be employed for more testing and validation in the future. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
25. Numerical and experimental study of flow around a golf ball with dimples by Laser-Doppler anemometer technique.
- Author
-
Ayed, Sadoon K., Habeeb, Laith Jaafer, and Mohammed, Emad S.
- Subjects
GOLF balls ,COMPUTATIONAL fluid dynamics ,FLOW velocity ,FLUID flow ,ANEMOMETER - Abstract
Many engineering applications have a flow of bluff body like flow over a spherical object, though it was not investigated thoroughly due to the difficulty in the real-life manufacturing and approach of computational fluid dynamics (CFD). Flow pattern and Hydrodynamics of the flow around the spherical object are the chief tasks to investigate. This paper study the flow of fluid over a golf ball with dimples both experimentally and numerically. The experimental measuring section consists of a square cross-section channel with the dimpled golf ball placed inside whereas RANS equations were solved for the numerical simulations. Three diverse flow regimes were used for the flow field velocity for the experimental and numerical investigations (Re = 8×103, 2×104, and 4×104). Moreover, the Reynolds numbers range was widened in the numerical investigations to (Re = 270×106). For the turbulent numerical simulations, the RANS model was utilized which gave good results compared to the other turbulent models. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
26. Spherical winding and helicity.
- Author
-
Xiao, Daining, Prior, Christopher B, and Yeates, Anthony R
- Subjects
ANEMOMETER ,TOPOLOGICAL property ,GAUGE invariance ,VECTOR fields ,CONSERVED quantity - Abstract
In ideal magnetohydrodynamics, magnetic helicity is a conserved dynamical quantity and a topological invariant closely related to Gauss linking numbers. However, for open magnetic fields with non-zero boundary components, the latter geometrical interpretation is complicated by the fact that helicity varies with non-unique choices of a field's vector potential or gauge. Evaluated in a particular gauge called the winding gauge, open-field helicity in Cartesian slab domains has been shown to be the average flux-weighted pairwise winding numbers of field lines, a measure constructed solely from field configurations that manifest its topological origin. In this paper, we derive the spherical analogue of the winding gauge and the corresponding winding interpretation of helicity, in which we formally define the concept of spherical winding of curves. Using a series of examples, we demonstrate novel properties of spherical winding and the validity of spherical winding helicity. We further argue for the canonical status of the winding gauge choice among all vector potentials for magnetic helicity by exhibiting equivalences between local coordinate changes and gauge transformations. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
27. Disaster for Darwin vs Australia on Fire--a Politico-Legal Review of Governments in Action.
- Author
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Scutt, Jocelynne
- Subjects
EMERGENCY management ,CLIMATE change ,WILDFIRES ,ANEMOMETER - Abstract
For two days in December 1974, from 24 to 26 December, Cyclone Tracy hit Darwin, in the Northern Territory of Australia, killing 71 people, seriously injuring 145, causing minor injuries to 500, damaging buildings, tearing roofs from houses, sweeping up trees and rubbish bins, rending children's playground equipment, and bending in half the anemometer needle in Darwin Airport control tower. The festive season ended with a damage bill topping AUD$800 million. From June 2019 through to March/April 2020, bushfires ravaged Australia, burning 10 million hectares, ending lives and destroying livelihoods, killing or injuring some three billion animals, with kangaroos leaping to avoid the inferno, while koalas whimpered as the oncoming flames sped towards them, filling the Australian bush with the agonised cries of animals in danger, distress, dying and death. Some 3,500 homes were burned out, almost 6,000 outbuildings demolished, 34 people killed, more injured, and the cost in monetary terms was estimated at over AUD$103 billion. During Black Summer, the Australian land expanse devastated was as if, were the conflagration to be experienced in England, the entire country would burn from Dover to the Scots' border. These disasters found both serving prime ministers absent overseas at crucial times. Gough Whitlam, prime minister during the cyclone disaster, returned from Greece immediately. Scott Morrison, prime minister during the fires, left in the midst of the conflagration. Whitlam set up a Darwin Reconstruction Commission. No Bushfire Reconstruction Commission was established by Morrison. Two different leaders, two different responses from government. This paper explores the disasters and the differences, the politico-legal dimensions of the way governments can respond or fail, and the process of recovery. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
28. Measuring flow velocity at elevated temperature with a hot wire anemometer calibrated in cold flow
- Author
-
Stephen F. Benjamin and Carol A. Roberts
- Subjects
Fluid Flow and Transfer Processes ,Work (thermodynamics) ,Materials science ,business.industry ,Mechanical Engineering ,Short paper ,Modified method ,Mechanics ,Atmospheric temperature range ,Condensed Matter Physics ,Optics ,Creep ,Flow velocity ,Anemometer ,Range (statistics) ,business - Abstract
Correction factors enable a hot wire anemometer calibrated at room temperature to be utilised at elevated temperature. This short paper reviews the equations on which those correction factors are based. The standard methods of correction, which work only over moderate temperature changes of a few degrees in the ambient, have been investigated over a greater temperature range. Modified correction factors are effective over a velocity range of 0–14 m/s and temperature range of 300–500 K. The modified method of correction has been developed during research into the warm up of automotive catalysts and this has prescribed the range of velocity and temperature considered.
- Published
- 2002
29. EVALUATION OF A AIR-CARRIER SPRAYER PROVIDED WITH SPRAYING BOOM EQUIPPED WITH DEFLECTING PROFILES.
- Author
-
Glodeanu, Mihnea, Vasile, Cristian, and Alexandru, Tudor
- Subjects
AIRLINE industry & the environment ,SPRAYING ,ORCHARD management ,VELOCITY distribution (Statistical mechanics) ,ANEMOMETER ,DEFLECTION (Mechanics) - Abstract
A air-carrier (air blast) sprayers, frequently used like spray equipment for orchards was tested in traveling conditions, in order to establish spray deposition at different locations (heights) and also the relationship between air velocity distribution and spray deposition. Another important issue was determining the uniformity of distribution to the direction of the travel. For that purpose were used samples of tissue paper placed in a vertical plane, at three different distances from the center line of the sprayer. In order to quantify spray deposition on the traveling direction, placing samples of tissue paper was also made on this direction. Spray solution was applied at 1200 L/ha volume rate, at a displacement velocity of 3,2 km/h. Measurements of air velocity in traveling conditions were achieved using a wire anemometer, set at each location. Spray deposition decrease with increasing of work height, distance from the fan outlet, and also with the decreasing of air velocity. [ABSTRACT FROM AUTHOR]
- Published
- 2016
30. MHD flow of MgO-Ag/water hybrid nanofluid past a moving slim needle considering dual solutions: an applicable model for hot-wire anemometer analysis.
- Author
-
Dinarvand, Saeed, Mousavi, Seyed Mehdi, Yousefi, Mohammad, and Nademi Rostami, Mohammadreza
- Subjects
NANOFLUIDICS ,NANOFLUIDS ,FINITE difference method ,MAGNETOHYDRODYNAMICS ,ANEMOMETER ,NUSSELT number ,PRANDTL number - Abstract
Purpose: The purpose of this paper is to study the steady laminar magnetohydrodynamics (MHD) flow of a magnesium oxide-silver/water hybrid nanofluid along a horizontal slim needle with thermal radiation by considering dual solutions. Design/methodology/approach: It is assumed that the needle can move in the same or opposite direction of the free stream. Also the solid phase and fluid phase are in thermal equilibrium. The basic partial differential equations become dimensionless using a similarity transformation method. Moreover, problem coding is accomplished using the finite difference method. The emerging parameters are nanoparticles mass (0–40 gr), base fluid mass (100 gr), needle's size (0.001–0.2), magnetic field parameter, velocity ratio parameter, radiation parameter and Prandtl number (6.2). Findings: With help of the stability analysis, it is shown that always the first solutions are physically stable. Results indicate that the magnetic parameter and the second nanoparticle's mass limit the range of the velocity ratio parameter for which the solution exists. Besides, the magnetic parameter leads to decrease of quantities of engineering interest, i.e. skin friction coefficient and local Nusselt number. Originality/value: To the best of the authors' knowledge, no one has ever attempted to study the present problem through a mass-based model for hybrid nanofluid. Moreover, the dual solutions for the problem are new. Indeed, the results of this paper are purely original and the numerical achievements were never published up to now. Finally, the authors expect that the present investigation would be useful in hot-wire anemometer or shielded thermocouple for measuring the velocity of the wind, etc. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
31. Experimental investigation on effect of partial flexibility at low aspect ratio airfoil – Part I: Installation on suction surface.
- Author
-
Genç, Mustafa Serdar, Açıkel, Halil Hakan, and Koca, Kemal
- Subjects
BIOLOGICAL membranes ,REYNOLDS number ,VELOCITY ,ANEMOMETER ,TURBULENCE - Abstract
Effects of flexible membrane mounted over suction surface of NACA 4412 airfoil were experimentally investigated at Reynolds number of 5x104 and low aspect ratio (AR=1) in this paper. The smoke-wire visualization method has been performed for flow visualization to demonstrate flow phenomena as laminar separation bubble (LSB), leading edge separation at z/c=0.4 and tip vortices at z/c=0.1. Values of velocity, Reynolds stress and turbulence statistics were measured by means of a constant temperature anemometer (CTA) system. Results of smoke-wire experiment revealed that size and height of LSB formed along z/c=0.4 at lower angles of attack such as α=8° was mitigated. Moreover, stall phenomenon as a result of boundary layer separation was apparently postponed at higher angles of attack. Velocity value was increased, whereas values of Reynold stress and turbulent kinetic energy was decreased with reduction of amount of fluctuations in flow. Consequently, using flexible membrane over suction surface of airfoil allowed the LSB to be mitigated or extinguished, resulting in exhibition of more stable flow characteristics. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
32. An assembled hot wire anemometer design.
- Author
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Xingxing Yao, Fanhao Shen, Yuan Zheng, and Ting Xiao
- Subjects
- *
AIR speed , *ANEMOMETER , *THERMAL equilibrium , *WIRE , *AIRPORTS - Abstract
The hot wire anemometer is a widely utilized device in laboratory settings for measuring air speed. This paper investigates the relationship between air speed and hot wire temperature across various air speed ranges, employing the theory of thermal equilibrium. We designed a measurement circuit and hot wire shape based on the hot wire anemometer principle, and validated the linear relationship between current and temperature at different air speeds within an adjustable air speed field. The measured current serves as a representative of air speed. Experimental validation of the designed hot wire anemometer demonstrates accurate measurement results that align with theoretical values across different air speed ranges. Finally, we determined the sensitivity of the anemometer in various measurement ranges, considering the instrument's uncertainty and measurement formula. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Turbulence intensity footprints of built and natural environment as measured by anemometers at Hong Kong International Airport.
- Author
-
KRÜS, HENK W., KAI KWONG HON, and PAK WAI CHAN
- Subjects
INTERNATIONAL airports ,TURBULENCE ,BUILT environment ,ANEMOMETER ,WIND measurement ,HANGARS ,RUNWAYS (Aeronautics) - Abstract
Terrain and building-induced low-level turbulence is studied in this paper. Data from six anemometers, respectively along the North and South Runways of Hong Kong International Airport, are analysed over the period of 2012 to 2018. From this data the recorded turbulence intensities have been computed and the footprints plotted. A joint analysis of the turbulence footprints together with the surrounding environment, using maps and photographs, reveals likely upstream causes influencing the directional distribution of observed turbulence intensities. Signatures from nearby objects and buildings, such as terminals and hangars, are easily identifiable. This paper serves as a unique documentation of possible building influence on wind measurements at a densely-developed, major international airport, and provides useful reference to meteorologists and wind engineers at airports in other parts of the world. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
34. Research on Location Selection of Personnel Door and Anemometer Based on FLUENT.
- Author
-
Qin, Tao, Zhang, Teng, Duan, Yanwei, and Liu, Yongli
- Subjects
EMPLOYEE selection ,AIR speed ,MINE ventilation ,ANEMOMETER ,MINES & mineral resources ,VENTILATION ,AIR pressure ,UNIFIED modeling language - Abstract
The structural design of ventilation structures and the arrangement of anemometers in the main ventilation roadway of an underground mine play an important role in the accurate measurement of air speed. It is one of the important tasks of mine ventilation management and intelligent-ventilation-system construction to determine the position of anemometers. In this paper, the CFD numerical simulation method is used to determine the position of the personnel door in the automatic air door by FLUENT software simulating and analyzing the air-speed cloud diagram and air-pressure cloud diagram in the two-dimensional roadway model. Under the same air speed, comparing the air-speed distribution of different cross-sections in the three-dimensional roadway model when the wide door and the personnel door are opened, the anemometer is set at the 25 m cross-section behind the air door, and the air-speed distribution of the cross-section at different air speeds is simulated. The average air-speed line and the specific installation position of the anemometer on the line are obtained by Origin software. The result shows that the position of the personnel door is 400 mm from the middle line of the roadway, and the measurement error of the anemometer is small on the left side of the roadway (0.41, 2.45) and the right side of the roadway (4.59, 2.43) at 25 m behind the air door, which provides a theoretical basis for the measurement of air speed in a coal mine ventilation roadway. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
35. Distribution of gas flow parameters at the outlet of structured packing.
- Author
-
Zhukov, V. E., Pavlenko, A. N., Sukhorukova, E. Yu., and Chernyavskiy, A. N.
- Abstract
Data of experimental studies on hydrodynamics of countercurrent flows of liquid and vapor in distillation columns with structured packings are necessary for verification of computational models that describe hydrodynamics and processes of heat and mass transfer in industrial distillation columns. The paper presents a description of the design of a multipoint hot-wire anemometer with a coordinate device, developed to measure the vapor flow rate under the conditions of packing jet irrigation with a countercurrent flow of freon mixture phases. The measurement system was tested with air flowing through a 210-mm layer of Sulzer 500X structured packing. The measurements were carried out using a large-scale research model of a distillation column with a diameter of 900 mm. Experimental data were obtained on the distribution of the local air flow velocity at the outlet of a single-layer Sulzer 500X packing. Scanning the packing plug with a step of 1 and 5 mm showed the presence of a periodic cellular pattern of the gas flow velocity distribution, which correlates with the structure of the studied packing. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
36. Performance Monitoring of Mast-Mounted Cup Anemometers Multivariate Analysis with ROOT.
- Author
-
Mangano, Salvatore, Vega, Enrique, Martínez, Alejandro, Alfonso-Corcuera, Daniel, Sanz-Andrés, Ángel, and Pindado, Santiago
- Subjects
ATMOSPHERIC turbulence ,ANEMOMETER ,MULTIVARIATE analysis ,WIND speed ,PARTICLE physics ,WIND speed measurement - Abstract
This paper analyzes the field performance of two cup anemometers installed in Zaragoza (Spain). Data acquired over almost three years, from January 2015 to December 2017, were analyzed. The effect of the different variables (wind speed, temperature, harmonics, wind speed variations, etc.) on two cup anemometers was studied. Data analysis was performed with ROOT, an open-source scientific software toolkit developed by CERN (Conseil Européen pour la Recherche Nucléaire) for the study of particle physics. The effects of temperature, wind speed, and wind dispersion (as a first approximation to atmospheric turbulence) on the first and third harmonics of the anemometers' rotation speed (i.e., the anemometers' output signature) were studied together with their evolution throughout the measurement period. The results are consistent with previous studies on the influence of velocity, turbulence, and temperature on the anemometer performance. Although more research is needed to assess the effect of the anemometer wear and tear degradation on the harmonic response of the rotor's angular speed, the results show the impact of a recalibration on the performance of an anemometer by comparing this performance with that of a second anemometer. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
37. Flow Study on the Anemometers of the Perseverance Based on Towing Tank Visualization.
- Author
-
Rodríguez-Sevillano, Ángel Antonio, Casati-Calzada, María Jesús, Bardera-Mora, Rafael, Feliz-Huidobro, Alejandro, Calle-González, Claudia, and Fernández-Antón, Jaime
- Subjects
ANEMOMETER ,TOWING basins ,VISUALIZATION ,HYDRODYNAMICS ,REYNOLDS number - Abstract
Flow visualization is necessary in fields such as engineering, since it allows us to know what is happening around the element being studied by means of a preliminary method, although it is relatively close to future research and computation methodology. The present project studies the interference at the anemometers of the Mars rover Perseverance, caused by the mast holding one of its cameras. After obtaining the model, manufactured by a 3D printer, it was placed inside a hydrodynamic towing tank, and red dye was added for a visual observation of the interference during the experiment. A comparison was made between the results achieved and those seen in a wind tunnel, realizing the high correlation they have. Finally, this paper promotes the use of the hydrodynamic towing tank in preliminary studies due to its low costs, considering the adequate comparison with other higher precision methodologies. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
38. Near-surface wind profile test based on accuracy verification of UAV anemometer lifting height in an urban fringe built-up area.
- Author
-
Ding, Wei, Chen, Hong, Chang, Han, Wang, Yupeng, Zhou, Dian, and Feng, Wei
- Subjects
URBAN fringe ,ANEMOMETER ,WIND speed ,DRONE aircraft ,RESIDENTIAL areas ,CITIES & towns - Abstract
Multirotor UAVs (unmanned aerial vehicles) have been widely used in urban vertical wind environment testing, whereas less attention has been given to the accuracy of wind speed captured by anemometers as drones fly. This paper aims to identify the ideal location of the anemometer on the UAV to obtain more accurate wind speeds and to assess the variation characteristics of wind speed in different spatial types in urban fringe areas. Accuracy verification of the lifting height of the anemometer in the UAV and wind profile test was carried out at three locations (a tennis court, a residential area, and a green park) on the iHarbour campus of Xi'an Jiaotong University. The following results were obtained: (1) the background wind speed was captured more accurately (R = 0.727, P = 0.001) when the lifting height of the anemometer was 0.00 m (as the height of the anemometer was the same as the rotors) and when the multirotor UAV was hovering in the air. However, this optimal lifting height lost 29.6% of the accuracy for capturing the background wind speed. Interestingly, when the lifting height was 0.75 m, the anemometer captured by the anemometer on the drone showed a significant negative correlation (R = − 0.682, P = 0.005) with the background wind speed. (2) The wind speed at an altitude of 1.5 m in the residential area was significantly lower than that noted at other heights, and the wind speed at 24 m was significantly lower than that at 100 m. (3) In addition, a sudden increase in wind speeds was always observed near the surface of 12 m inside the campus, which may be due to the interaction of hot surface air in this newly built-up area with the cool rural winds around it. The study presents methods and quantitative references for the application of multirotor UAVs in urban vertical wind environment testing and the evaluation of ventilation performance at different heights inside high-rise houses in urban fringe areas. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
39. A Review of Wind Speed Estimation for Wind Turbine Systems Based on Kalman Filter Technique.
- Author
-
Khoshrodi, M. Najafi, Jannati, Mohammad, and Sutikno, Tole
- Subjects
WIND speed ,WIND turbine maintenance & repair ,KALMAN filtering ,PARAMETER estimation ,ANEMOMETER - Abstract
This paper presents a review of wind speed estimation based on Kalman filter technique applied to wind turbine systems. Generally, wind speed measurement is performed by anemometer. The wind speed provided by the anemometer is measured at a single point of the rotor plane which is not the accurate wind speed. Also, using anemometer increases the system cost, maintenance, complexity and reduces the reliability. For these reasons, estimation of wind speed is needed for wind turbine systems. In this paper, the several wind speed estimation methods based on Kalman filter method used for wind turbine systems are reviewed. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
40. Measuring Relative Wind Speeds in Stratospheric Balloons with Cup Anemometers: The TASEC-Lab Mission.
- Author
-
Alfonso-Corcuera, Daniel, Ogueta-Gutiérrez, Mikel, Fernández-Soler, Alejandro, González-Bárcena, David, and Pindado, Santiago
- Subjects
WIND speed measurement ,ANEMOMETER ,WIND speed - Abstract
This paper shows wind speed measurements from the TASEC-Lab experiment in a stratospheric balloon mission. The mission was launched in July 2021 from León (Spain) aerodrome. Measurements of horizontal wind speed in relation to the balloon gondola were successfully carried out with a cup anemometer. According to the available literature, this is the first time a cup anemometer has been used in a stratospheric balloon mission. The results indicate the need to consider the horizontal wind speed from the balloon ascent phase for thermal calculations of the mission. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
41. Force Transducer Through Total Internal Reflection and Frustrated Total Internal Reflection for a Three-Axis Anemometer.
- Author
-
Hirano, John and Garmire, David
- Abstract
This paper introduces a method for measuring forces applied in a normal direction to the device using frustrated total internal reflection (FTIR) and infrared technology. Using FTIR for measuring force is not a new concept, but the past systems have used this principle by changing the material at the surface to change the refractive index at the point of contact. The design we propose causes a physical deformation to the waveguide, which causes changes in the output of the transducer. The transducer is designed to be implemented in a low cost three-axis anemometer for use in high-spatial resolution data gathering for wind generation stabilization. Our data supports the design of our transducer as it shows a correlation between the force and deformation of the upper surface of the waveguide and the output of the infrared phototransistor. The final section of the paper suggests a new design for a three-axis anemometer using the newly developed transducer. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
- Full Text
- View/download PDF
42. Visualization Study of the Effect of the Prolonged Vertical Tube on the Separation Performance of a Cyclone.
- Author
-
Qian, Fuping and Zhang, Mingyao
- Subjects
MACHINE separators ,MANUFACTURING processes ,ANEMOMETER ,VISUAL perception ,ATOMIZERS - Abstract
Cyclones have been widely used in different industrial processes. The most widely used experimental observation techniques for the flow pattern include Pitot tubes; hot-wire anemometers, as well as the non-intrusive techniques such as laser Doppler anemometry (LDA). However, all these available techniques have the limitation of only one-point measurement at a time, by which the whole-field fluid characterization in cyclones cannot be obtained simultaneously. Particle image velocimetry (PIV) is a novel non-intrusive visualization experimental technique to measure the whole-field three-dimensional fluid velocity instantaneously. However, only a few papers that examined the flow pattern in cyclones with PIV have been found. The objective of this work is to carry out an elementary experimental investigation of the effect of the prolonged vertical tube on the separation performance of a cyclone by PIV. Since the tangential velocity results in the centrifugal force for particle separation, and is regarded as the most important component of the gas flow in a cyclone, this paper only presents this velocity component. To facilitate visual observation all cyclone parts are constructed of perspex. The lengths of the prolonged vertical tube (attaching a vertical tube at the bottom of the dust outlet) are 0.30m, 0.40m and 0.50m, respectively. Experiments were conducted at 18m/s inlet gas velocity. The model cyclone is set horizontally in order to take images by charge coupled device (CCD) easily. Particles of about 1 μm in diameter are added as tracer particles. They are generated by the atomizer. Air with tracer particles is sucked into the cyclone through the entry, subsequently travels through outlet tube of the cyclone and the gate valve, and is discharged into the atmosphere. The experimental results show that a typical Rankine vortex with inner quasi-forced vortex and outer quasi-free vortex in the vertical tube and dustbin which are the same as that in the body of the cyclone; the tangential velocity in the dustbin reduces1 greatly when the prolonged vertical tube attaching into the dust outlet, which can avoid the re-entrainment of already separated dust effectively. The results also indicate that PIV technique can be used to measure the strong swirl gas flow such as cyclones, and the prolonged vertical tube has practical significance for improving the separation performance of a cyclone. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
43. THERMO-ANEMOMETRIC DETERMINATION OF LIQUID WATER CONTENT IN WET AIRSTREAM.
- Author
-
JANKŮ, Rostislav and HORÁK, Vladimír
- Subjects
HYDROMETEOROLOGY ,ATMOSPHERIC water vapor measurement ,ANEMOMETER ,CLOUD classification ,ICE prevention & control ,AERONAUTICAL safety measures - Abstract
The paper is focused on the experimental study of possibilities of the thermo-anemometric analysis for determination of the liquid water content in the stream of wet air. The developed method is based on the measurement and comparison of stream velocity of wet and dry air by the hot-wire thermal anemometric probe. Experiments were performed in the small icing wind tunnel using the standard thermal anemometer Testo 425. There was found the correlation between the liquid water content and the difference in measured velocity of the wet and dry airstreams. The conclusion of the paper pays attention for the interpretation and formulation the final analyses and recommendations. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
44. A Hot-Wire Anemometer with Automatically Adjusted Dynamic Properties for Wind Energy Spectrum Analysis.
- Author
-
Ligęza, Paweł and Jamróz, Paweł
- Subjects
WIND power ,ANEMOMETER ,WIND turbines ,SPECTRUM analysis ,FLOW measurement ,DOPPLER lidar - Abstract
Hot-wire anemometric measurements are often related to the determination of flow parameters in a high frequency range. Such knowledge is particularly important when analyzing the flow phenomena in the vicinity of wind turbines. The reliability of obtained results is determined by the knowledge of the properties of the system used for measurements. It concerns both the static and dynamic characteristics of individual measurement channels. In studies of hot-wire anemometric systems, a problem related to the unstable transmission bands of such systems and their high dependence on measurement conditions and the system configuration itself has been commonly indicated. This paper presents the results of an investigation of a new type of hot-wire anemometer, allowing for automatic adjustment of its dynamic characteristics under real working conditions. The presented system is dedicated to the analysis of the wind energy spectrum in experimental laboratory tests on reduced-scale models and to specialized in situ measurements. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
45. Semi-Empirical Approach to Gas Flow Velocity Measurement by Means of the Thermal Time-of-Flight Method—Further Investigation.
- Author
-
Sobczyk, Jacek
- Subjects
GAS flow ,FLOW measurement ,VELOCITY measurements ,GAS mixtures ,ANEMOMETER ,FLOW velocity - Abstract
This paper describes a study to expand the knowledge as to whether a thermal wave anemometer can be used to measure the velocity of flowing gases or gas mixtures in situ. For this purpose, several series of measurements were performed in laboratory conditions using both the previously used probe and other probes of similar design. The probes were not modified mechanically or electrically in any way. The obtained results were compared with each other, and on this basis, the optimal, though purely empirical, form of the calibration function was determined (4). The analysis of the relative differences between the measured and set velocity values showed that they do not exceed 1% in the velocity range from 0.05 to 2.5 m/s. Lowering the sensitivity of the method for velocities below approx. 0.05 m/s results in a rapid increase in the observed deviations, reaching 15% for 0.015 m/s. The conducted research also revealed an increased resistance of the proposed measurement method to small flow disturbances, both longitudinal and transverse, and a reduced sensitivity to non-optimal positioning of the probe in relation to the flow direction, relative to the methods using both detectors. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
46. Three-Component Constant Temperature Anemometer CTA3-2: Calibration and Application.
- Author
-
Budovsky, A. D., Sidorenko, A. A., Polivanov, P. A., Kornev, E. V., Salenko, S. D., and Obuhovsky, A. D.
- Subjects
ANEMOMETER ,FLUID flow ,JETS (Fluid dynamics) ,AERODYNAMICS ,FLUID dynamics - Abstract
The study deals with three-component hot-wire anemometer designed and manufactured in ITAM SB RAS. The paper presents the calibration technique of designed and manufactured three-wire probes and describes the data obtained in testing experiments on measurements of steady and unsteady parameters of the flow in subsonic turbulent jet. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
47. Temperature Effect and Its Compensation of a Micromachined 2-D Anemometer.
- Author
-
Gao, Shixuan, Yi, Zhenxiang, Ye, Yizhou, Qin, Ming, and Huang, Qing-An
- Abstract
This paper presents a semi-empirical model for the temperature effect of a micromachined 2-D anemometer. The anemometer consists of a self-heated double Wheatstone bridge. Eight thermistors are symmetrically arranged in two orthogonal directions, and four of them in each direction make up a Wheatstone bridge. The eight thermistors simultaneously act as both heating and sensing elements. The terminal voltage across the bridge and the bridge output voltage, under the constant current supply, are utilized to measure the wind speed and direction, respectively. The semi-empirical model has taken the thermal physical properties of the air, sensor substrate, and thermistors into account. It shows that the measurement of wind direction has a weak temperature dependence due to the symmetric config uration of the self-heated double Wheatstone bridge, which suppresses the temperature drift. The temperature compensation has been performed by means of the semi-empirical model. The experimental measurements demonstrate that, when the air temperature changes from 270 to 310 K, the wind speed varies from 0 to 30 m/s with an error less than ±1.5 m/s while the wind direction spans from 0° to 360° with the weak temperature dependence. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
48. Local turbulence parameterization improves the Jensen wake model and its implementation for power optimization of an operating wind farm.
- Author
-
Duc, Thomas, Coupiac, Olivier, Girard, Nicolas, Giebel, Gregor, and Göçmen, Tuhfe
- Subjects
WIND turbines ,WIND power plants ,EXPERIMENTAL agriculture ,TURBULENCE ,ANEMOMETER - Abstract
In this paper, a new calculation procedure to improve the accuracy of the Jensen wake model for operating wind farms is proposed. In this procedure, the wake decay constant is updated locally at each wind turbine based on the turbulence intensity measurement provided by the nacelle anemometer. This procedure was tested against experimental data at the Sole du Moulin Vieux (SMV) onshore wind farm in France and the Horns Rev-I offshore wind farm in Denmark. Results indicate that the wake deficit at each wind turbine is described more accurately than when using the original model, reducing the error from 15% to 20% to approximately 5%. Furthermore, this new model properly calibrated for the SMV wind farm is then used for coordinated control purposes. Assuming an axial induction control strategy, and following a model predictive approach, new power settings leading to an increased overall power production of the farm are derived. Power gains found are on the order of 2.5% for a two-wind-turbine case with close spacing and 1% to 1.5% for a row of five wind turbines with a larger spacing. Finally, the uncertainty of the updated Jensen model is quantified considering the model inputs. When checked against the predicted power gain, the uncertainty of the model estimations is seen to be excessive, reaching approximately 4%, which indicates the difficulty of field observations for such a gain. Nevertheless, the optimized settings are to be implemented during a field test campaign at SMV wind farm in the scope of the national project SMARTEOLE. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
49. A Hybrid Beam-Forming and Direction-Finding Method for Wind Direction Sensing Based on HF Radar.
- Author
-
Zhao, Chen, Chen, Zezong, He, Chao, Xie, Fei, and Chen, Xi
- Subjects
PHASED array radar ,REMOTE sensing ,ANEMOMETER ,RADAR ,SHORTWAVE radio - Abstract
Recent studies indicate that the poor antenna sidelobe level of phased-array high-frequency (HF) radars degrades the performance of Bragg ratio estimation for wind direction measurements. To explore this issue, this paper improves the previous model of wind direction estimation for phased-array HF radars, and the effect of unsatisfactory array patterns on Bragg ratio estimation is theoretically analyzed. Moreover, a hybrid beam-forming and direction-finding method, in which wind direction is measured by reducing the influence of unsatisfactory array patterns on Bragg ratio estimation, is proposed for multifrequency HF radars installed along the coast of Zhejiang Province in China. The procedure for implementing this scheme is also presented in detail. Wind directions derived from 8.05-, 10.7-, 16.8-, and 19.2-MHz radar data are compared with measurements collected with anemometers at three sampling locations to verify the proposed method, and the measurements with root-mean-square errors from 19.5° to 26.6° show that this strategy is effective for wind direction measurements. We recommend adopting the proposed method or using similar approaches to estimate wind direction based on HF radars, especially in situations where the array pattern is not sufficiently narrow. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
50. Experimental and computational investigation of a centrifugal compressor stage.
- Author
-
Gao, L., Xi, G., Zhou, L., and Wang, S.
- Subjects
ANEMOMETER ,COMPRESSORS ,UNSTEADY flow ,FLUID dynamics ,MATHEMATICAL models - Abstract
This paper presents experimental and computational investigations on a centrifugal compressor stage to study unsteady interaction flow and to verify the capability of computational fluid dynamics (CFD) codes. Detailed instantaneous flow has been measured at several different measuring positions using a hot-wire anemometer with the phase-locked ensemble-averaged technique. To describe quantitatively the unsteady effect induced from the impeller, an unsteady intensity is defined in this paper. Also, two computational investigations for the tested centrifugal compressor are performed and compared with corresponding experimental data: one is a steady method with the deterministic stress model and the other is an unsteady method with the sliding interface technique. [ABSTRACT FROM AUTHOR]
- Published
- 2005
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