1、Designation: D5527 00 (Reapproved 2017)1Standard Practices forMeasuring Surface Wind and Temperature by AcousticMeans1This standard is issued under the fixed designation D5527; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEWarning notes were editorially updated throughout in March 2017.1. Scope1.1 These practices cover procedures for measur
3、ing one-,two-, or three-dimensional vector wind components and sonictemperature by means of commercially available sonicanemometer/thermometers that employ the inverse time mea-surement technique. These practices apply to the measurementof wind velocity components over horizontal terrain usinginstru
4、ments mounted on stationary towers. These practices alsoapply to speed of sound measurements that are converted tosonic temperatures but do not apply to the measurement oftemperature by the use of ancillary temperature devices.1.2 The values stated in SI units are to be regarded asstandard. No other
5、 units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of
6、regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Tra
7、de Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1356 Terminology Relating to Sampling and Analysis ofAtmospheresD3631 Test Methods for Measuring Surface AtmosphericPressureD4230 Test Method of Measuring Humidity with Cooled-Surface Condensation
8、(Dew-Point) HygrometerE337 Test Method for Measuring Humidity with a Psy-chrometer (the Measurement of Wet- and Dry-Bulb Tem-peratures)IEEE/ASTM SI-10 American National Standard for Use ofthe International System of Units (SI): The Modern MetricSystem3. Terminology3.1 DefinitionsRefer to Terminology
9、 D1356 for commonterminology.3.2 Definitions of Terms Specific to This Standard:3.2.1 acceptance angle (6, deg) the angular distance,centered on the array axis of symmetry, over which thefollowing conditions are met: (a) wind components are unam-biguously defined, and (b) flow across the transducers
10、 isunobstructed or remains within the angular range for whichtransducer shadow corrections are defined.3.2.2 acoustic pathlength (d, (m)the distance betweentransducer transmitter-receiver pairs.3.2.3 sampling period(s)the record length or time intervalover which data collection occurs.3.2.4 sampling
11、 rate (Hz)the rate at which data collectionoccurs, usually presented in samples per second or Hertz.3.2.5 sonic anemometer/thermometeran instrument con-sisting of a transducer array containing paired sets of acoustictransmitters and receivers, a system clock, and microprocessorcircuitry to measure i
12、ntervals of time between transmission andreception of sound pulses.3.2.5.1 DiscussionThe fundamental measurement unit istransit time. With transit time and a known acoustic pathlength,velocity or speed of sound, or both, can be calculated.Instrument output is a series of quasi-instantaneous velocity
13、component readings along each axis or speed of sound, or both.The speed of sound and velocity components may be used tocompute sonic temperature (Ts), to describe the mean windfield, or to compute fluxes, variances, and turbulence intensi-ties.1These practices are under the jurisdiction of ASTM Comm
14、ittee D22 on AirQuality and are the direct responsibility of Subcommittee D22.11 on Meteorology.Current edition approved March 1, 2017. Published March 2017. Originallyapproved in 1994. Last previous edition approved in 2011 as D5527 00 (2017).DOI: 10.1520/D5527-00R17E01.2For referenced ASTM standar
15、ds, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1
16、9428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Tec
17、hnical Barriers to Trade (TBT) Committee.13.2.6 sonic temperature (Ts), (K) an equivalent tempera-ture that accounts for the effects of temperature and moistureon acoustic wavefront propagation through the atmosphere.3.2.6.1 DiscussionSonic temperature is related to thevelocity of sound c, absolute
18、temperature T, vapor pressure ofwater e, and absolute pressure P by (1).3c25 403T 110.32e/P! 5 403Ts(1)(Guidance concerning measurement of P and e are con-tained in Test Methods D3631, D4230, and E337.)3.2.7 transducer shadow correctionthe ratio of the truealong-axis velocity, as measured in a wind
19、tunnel or by anotheraccepted method, to the instrument along-axis wind measure-ment.3.2.7.1 DiscussionThis ratio is used to compensate foreffects of along-axis flow shadowing by the transducers andtheir supporting structure.3.2.8 transit time (t, (s)the time required for an acousticwavefront to trav
20、el from the transducer of origin to thereceiving transducer.3.3 Symbols:B (dimensionless) squared sums of sines and cosines of wind directionangle used to calculate wind direction standarddeviationc (m/s) speed of soundd (m) acoustic pathlengthe (Pa) vapor pressure of waterf (dimensionless) compress
21、ibility factorP (Pa) ambient pressuret (s) transit timeT (K) absolute temperature, KTs(K) sonic temperature, K (dimensionless) specific heat ratio (cp/cv)M (g/mol) molar mass of airn (dimensionless) sample sizeR* (J/molK) the universal gas constantu (m/s) velocity component along the determined mean
22、 winddirectionus(m/s) velocity component along the array u axisv (m/s) velocity component crosswind to the determined meanwind directionvs(m/s) velocity component along the array v axisw (m/s) vertical velocityWS (m/s) scalar wind speed computed from measured velocitycomponents in the horizontal pla
23、ne (deg) determined mean wind direction with respect to truenorthr(deg) wind direction measured in degrees clockwise from thesonic anemometer + vsaxis to the along-wind u axis (deg) acceptance angle (deg) orientation of the sonic anemometer axis with respect tothe true north(deg) standard deviation
24、of wind azimuth angle3.4 UnitsUnits of measurement used should be in accor-dance with IEEE/ASTM SI-10.44. Summary of Practice4.1 Acalibrated sonic anemometer/thermometer is installed,leveled, and oriented into the expected wind direction to ensurethat the measured along-axis velocity components fall
25、 withinthe instruments acceptance angle.4.2 The wind components measured over a user-definedsampling period are averaged and subjected to a softwarerotation into the mean wind. This rotation maximizes the meanalong-axis wind component and reduces the mean cross-component v to zero.4.3 Mean horizonta
26、l wind speed and direction are computedfrom the rotated wind components.4.4 For the sonic thermometer, the speed of sound solutionis obtained and converted to a sonic temperature.4.5 Variances, covariances, and turbulence intensities arecomputed.5. Significance and Use5.1 Sonic anemometer/thermomete
27、rs are used to measureturbulent components of the atmosphere except for confinedareas and very close to the ground. These practices apply to theuse of these instruments for field measurement of the wind,sonic temperature, and atmospheric turbulence components.The quasi-instantaneous velocity compone
28、nt measurements areaveraged over user-selected sampling times to define meanalong-axis wind components, mean wind speed and direction,and the variances or covariances, or both, of individualcomponents or component combinations. Covariances are usedfor eddy correlation studies and for computation of
29、boundarylayer heat and momentum fluxes. The sonic anemometer/thermometer provides the data required to characterize the stateof the turbulent atmospheric boundary layer.5.2 The sonic anemometer/thermometer array shall have asufficiently high structural rigidity and a sufficiently lowcoefficient of t
30、hermal expansion to maintain an internal align-ment to within 60.1. System electronics must remain stableover its operating temperature range; the time counter oscilla-tor instability must not exceed 0.01 % of frequency. Consultwith the manufacturer for an internal alignment verificationprocedure.5.
31、3 The calculations and transformations provided in thesepractices apply to orthogonal arrays. References are alsoprovided for common types of non-orthogonal arrays.6. Interferences6.1 Mount the sonic anemometer probe for an acceptanceangle into the mean wind. Wind velocity components fromangles outs
32、ide the acceptance angle may be subject to uncom-pensated flow blockage effects from the transducers andsupporting structure, or may not be unambiguously defined.Obtain acceptance angle information from the manufacturer.6.2 Mount the sonic array at a distance that exceeds theacoustic pathlength by a
33、 factor of at least 2 from anyreflecting surface.6.3 To obtain representative samples of the mean wind, thesonic array must be exposed at a representative site. Sonicanemometer/thermometers are typically mounted over level,open terrain at a height of 10 m above the ground. Considersurface roughness
34、and obstacles that might cause flow block-age or biases in the site selection process.3The boldface numbers in parentheses refer to the list of references at the end ofthese practices.4Excerpts from IEEE/ASTM SI-10 are included in Vol 11.07.D5527 00 (2017)126.4 Carefully measure and verify array til
35、t angle and align-ment. The vertical component of the wind is usually muchsmaller than the horizontal components. Therefore, the verticalwind component is highly susceptible to cross-componentcontamination from tilt angles not aligned to the chosencoordinate system. A typical coordinate system may i
36、ncludeestablishing a level with reference to either the earth or to localterrain slope. Momentum flux computations are particularlysusceptible to off-axis contamination (2). Calculations andtransformations (Section 9) for sonic anemometer data arebased on the assumption that the mean vertical veloci
37、ty w! isnot significantly different from zero. Arrays mounted above asloping surface may require tilt angle adjustments. Also, avoidmounting the array close (within 2 m) to the ground surfacewhere velocity gradients are large and w may be nonzero.6.5 The transducers are tiny microphones and are, the
38、refore,sensitive to extraneous noise sources, especially ultrasonicsources at the anemometers operating frequency. Mount thetransducer array in an environment free of extraneous noisesources.6.6 Sonic anemometer/thermometer transducer arrays con-tribute a certain degree of blockage to flow. Conseque
39、ntly, themanufacturer should include transducer shadow corrections aspart of the instruments data processing algorithms, or definean acceptance angle beyond which valid measurements cannotbe made, or both.6.7 Ensure that the instrument is operated within its velocitycalibration range and at temperat
40、ures where thermal sensitivityeffects are not observed.6.8 These practices do not address applications where mois-ture is likely to accumulate on the transducers. Moistureaccumulation may interrupt transmission of the acoustic signal,or possibly damage unsealed transducers. Consult the manu-facturer
41、 concerning operation in adverse environments.7. Sampling7.1 The basic sampling rate of a sonic anemometer is on theorder of several hundred hertz. Transit times are averagedwithin the instruments software to produce basic measure-ments at a rate of 10 to 20 Hz, which may be user-selectable.This sam
42、pling is done to improve instrument measurementprecision and to suppress high frequency noise and aliasingeffects. The 10 to 20-Hz sample output in a serial digital datastream or through a digital to analog converter is the basic unitof measurement for a sonic anemometer.7.2 Select a sampling period
43、 of sufficient duration to obtainstatistically stable measurements of the phenomena of interest.Sampling periods of at least 10 min duration usually generatesufficient data to describe the turbulent state of the atmosphereduring steady wind conditions. Sampling periods in excess of1 h may contain un
44、desired trends in wind direction.8. Procedure8.1 Perform system calibration in a zero wind chamber(refer to the manufacturers instructions).8.2 Mount the instrument array on a solid, vibration-freeplatform free of interferences.8.3 Select an orientation into the mean flow within theinstruments accep
45、tance angle. Record the orientation anglewith a resolution of 1. Use a leveling device to position theprobe to within 60.1 of the vertical axis of the chosencoordinate system. (WarningWind measurements using asonic anemometer should only be made within the acceptanceangle.)8.4 Install cabling to the
46、 recording device, and keep cablingisolated from other electronics noise sources or power cables tominimize induction or crosstalk.8.5 As a system check, collect data for several sequentialsampling periods (of at least 10-min duration over a period ofat least 1 h) during representative operating con
47、ditions. Exam-ine data samples for extraneous spikes, noise, alignment faults,or other malfunctions. Construct summary statistics for eachsampling period to include means, variances, and covariances;examine these statistics for reasonableness. Compute 1-hspectra and examine for spikes or aliasing af
48、fecting the 53spectral slope in the inertial subrange.NOTE 1Calculations and transformations presented in these practicesare based on the assumption of a zero mean vertical velocity component.Deviation of the mean vertical velocity component from zero should notexceed the desired measurement precisi
49、on. Alignment or data reductionsoftware modifications not addressed in these practices may be needed forlocations where w is nonzero.8.6 Recalibrate and check instrument alignment at leastonce a week, whenever the instrument is subjected to asignificant change in weather conditions, or when transducersor electronics components are changed or adjusted.8.7 Check for bias, especially in w, using a data set collectedover an extended time period. The array support structure,topography, and changes in ambient temperature may producebiases in
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