1、Designation: D 5366 96 (Reapproved 2002)e1Standard Test Method forDetermining the Dynamic Performance of a Wind Vane1This standard is issued under the fixed designation D 5366; 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 (e) indicates an editorial change since the last revision or reapproval.e1NOTESeveral editorial changes were made throughout the standard in October 2002.1. Scope1.1 This test method covers the d
3、etermination of the startingthreshold, delay distance, and overshoot ratio of a wind vanefrom direct measurements in a wind tunnel. This test method isapplicable only to wind vanes having measurable overshoot.1.2 This test method provides for determination of theperformance of a system consisting of
4、 a wind vane and itsassociated position-to-output transducer in wind tunnel flow.Use of values determined by this test method to describeperformance in atmospheric flow of a wind direction measur-ing system incorporating the vane must be done with anunderstanding of the differences between the two s
5、ystems andthe two environments.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 regulatory limitatio
6、ns prior to use.2. Terminology2.1 Definitions:2.1.1 delay distance (D)the distance the air flows past awind vane during the time it takes the vane to return to 50 %of the initial displacement.2.1.2 overshoot (un)the amplitude of a deflection of awind vane as it oscillates about uBafter release from
7、an initialdisplacement.2.1.3 overshoot ratio (V)the ratio of two successiveovershoots, as expressed by the equation:V5un11!/un(1)where unand u(n+1)are the n and n + 1 overshoots, respec-tively. In practice, since deflections after the first (to the sideopposite the release point are normally small,
8、the initial releasepoint (that is, the n = 0 deflection) and the first deflection afterrelease (n = 1) are used in determining the overshoot ratio.2.1.4 starting threshold (Uo)the lowest speed at which thevane can be observed or measured moving from a 10 offset ina wind tunnel.2.2 Symbols:D (m) dela
9、y distanceUo(m/s) starting thresholdV (none) overshoot ratioh (none) damping ratiold(m) damped natural wavelengthun(degrees) overshoot; maximum angular excursionuo(degrees) reference directionuB(degrees) vane equilibrium positionuB uo(degrees) dynamic vane bias2.3 Calculated or Estimated Values:2.3.
10、1 damping ratio (h)calculated from the overshootratio (1,2).2h5ln1/V!p21 ln1/V!#2!0.5(2)2.3.2 damped natural wavelength (ld)at sea level in theU.S. Standard Atmosphere, damped natural wavelength isrelated to delay distance and damping ratio by the empiricalexpression (1,2).2ld5D6.0 2 2.4h!1 2h2!0.5(
11、3)3. Summary of Test Method3.1 Reference Direction (uo, degrees) is the indicatedangular position of the vane when aligned along the centerlineof the wind tunnel.3.2 Vane Equilibrium Position (uB, degrees) is the finalresting position of the vane after motion in response to aninitial displacement. I
12、deally, uB= uo.3.3 Dynamic Vane Bias (uB uo, degrees) is the displace-ment of the vane from the wind tunnel centerline at 5 m/s. This1This test method is under the jurisdiction of ASTM Committee D22 onSampling and Analysis of Atmospheres and is the direct responsibility of Subcom-mittee D22.11 on Me
13、terology.Current edition approved October 10, 1996. Published December 1996. Origi-nally published as D 5366 93. Last previous edition D 5366 95.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.1Copyright ASTM International, 100 Barr Harbor Drive, PO Bo
14、x C700, West Conshohocken, PA 19428-2959, United States.measurement will identify wind vanes with unbalanced aero-dynamic response because of damage (for example, bent tail)or poor design.3.4 Starting Threshold (Uo, m/s) is determined by observ-ing or measuring the lowest speed at which the vane, re
15、leasedfrom a 10 offset position in a wind tunnel, moves toward uB.Movement must be distinguishable from vibration.3.5 Delay Distance (D, m) may be determined at a numberof wind speeds but shall include 5 m/s and 10 m/s. It iscomputed from the time required for the vane to reach 50 % ofthe initial di
16、splacement from 10 off uB. This time in secondsis converted to delay distance by multiplying by the windtunnel speed in metres per second. Tests shall include an equalnumber of displacements to each side of uB.3.6 Overshoot Ratio (V) may be determined at the sametime as the delay distance. The maxim
17、um angular excursion onthe opposite side of uBfrom the initial 10 displacement fromuBis measured. This value is divided by the initial displacementto obtain V.4. Significance and Use4.1 This test method will provide a standard for comparisonof wind vanes of different types. Specifications by regulat
18、oryagencies and industrial societies (3-5) have stipulated perfor-mance values. This test method provides an unambiguousmethod for measuring starting threshold, delay distance, andovershoot ratio.5. Apparatus5.1 Wind Tunnel (6):5.1.1 SizeThe wind tunnel shall be large enough so thatthe total project
19、ed area of supports, sensor apparatus, and thevane in its displaced position is less than 5 % of the cross-sectional area of its test section.5.1.2 Speed RangeThe wind tunnel shall have a speedcontrol that will allow the flow rate to be varied from 0 to atleast 10 m/s. The speed control shall mainta
20、in the flow ratewithin 60.2 m/s.5.1.3 Turbulence and SwirlAcross the volume to beoccupied by the vane, the flow profile shall vary by no morethan 1 % about the mean speed and shall exhibit a turbulenceof less than 1 %. CAUTION: Swirl in the wind tunnel mayinfluence starting threshold measurements. V
21、ariations in themeasurement of uBa low speeds likely indicate the existence ofswirl.5.1.4 CalibrationThe mean flow rate shall be verified atthe mandatory speeds of 5 and 10 m/s by use of transferstandards that have been calibrated by the National Institute ofStandards and Technology (formerly called
22、 the National Bu-reau of Standards)3or by a fundamental physical method.5.1.4.1 Speeds below 2 m/s for threshold determinationshall be verified by a sensitive anemometer or by somefundamental time and distance technique, such as measuringthe transition time of smoke puffs, soap bubbles, or heat puff
23、sbetween two points separated by a known distance.5.1.5 EnvironmentThe temperature and pressure of theenvironment within the wind tunnel test section shall bereported. Differences of greater than 3 % in the density of airwithin the test environment may result in poor inter-comparability of independe
24、nt measurements of starting thresh-old, delay distance, and overshoot ratio since these values aredensity dependent.5.2 Measuring System:5.2.1 DirectionThe resolution of the wind vane position-tooutput transducer limits the resolution of the measure-ments. The accuracy of the positiontooutput conver
25、sion shallbe within 60.1. CAUTION: Avoid potentiometer dead spotsor crossover positions while performing these procedures.5.2.2 TimeThe resolution of time shall be consistent withthe distance accuracy required. For this reason, the timeresolution may be changed as the wind tunnel speed ischanged. Fo
26、r example, for a distance constant measurement to0.1 m, one must have a time resolution of 0.05 s at 2 m/s and0.01 s at 10 m/s. If time accuracy is based on commercialelectrical power frequency, it will be at least an order ofmagnitude better than the resolution suggested above.5.3 Signal Conditioni
27、ngCare shall be taken to avoidelectronic circuits in signal conditioning and recording devicesthat adversely affect the apparent vane performance. CAU-TION: Time constants in signal conditioning and recordingdevices shall be less than 0.01 s.5.4 Recording TechniquesThe measuring or recordingsystem s
28、hall represent the 10 displacement on each side of uBwith a resolution of 0.2. One simple technique is to use afast-response recorder (flat to 4060 Hz or better) with enoughgain so that a vane can be oriented in the wind tunnel with uBrepresented at mid-scale, and 610 of vane displacementtraversing
29、the full span of the recorder.5.4.1 The recorder shall have a fast chart speed of 50 mm/sor more. An alternative is to use an FM tape recorder to recordthe signal. When played back at lower speed, a proportionatelyslower analog strip chart recorder yielding an equivalent50-mm/s chart speed is accept
30、able. Oscilloscopes with memoryand hard copy capability may also be used.5.4.2 Digital recording and data reduction systems aresatisfactory if the sampling rate is at least 100 per second.6. Sampling6.1 Starting ThresholdTen consecutive tests at the samespeed meeting the test method requirement, fiv
31、e in eachdirection from uB, are required for a valid starting thresholdmeasurement.6.2 Delay Distance and Overshoot RatioThe arithmeticmean of ten tests, five in each direction from uB, is required fora valid measurement at each speed. The results of measure-ments at two or more speeds shall be aver
32、aged to a single valuefor delay distance and a single value for overshoot ratio.7. Procedure7.1 Dynamic Vane Bias:7.1.1 Set vane at tunnel centerline with no flow in the windtunnel.7.1.2 Adjust the wind tunnel to give a flow of 5 m/s.3Available from National Institute of Standards and Technology (NI
33、ST),Gaithersburg, MD 20899.D 5366 96 (2002)e127.1.3 Measure the equilibrium vane position (uB) relative tothe tunnel centerline (uo). The angular difference, uB uois thedynamic vane bias.7.1.4 A dynamic vane bias greater than 1 indicates poordesign or a problem with the vane. Appropriate corrections
34、shall be made before continuing.7.2 Starting Threshold:7.2.1 Provide a mechanical method for holding and releas-ing the vane at 10 6 1 from uB. With no flow in the windtunnel, verify that the vane moves by no more than 60.5 whenthe release mechanism is activated.7.2.2 Adjust the wind tunnel to a spe
35、ed expected to be lowerthan the starting threshold. Displace the vane by 10 and thenrelease it by the procedure described in 7.2.1. Observe themotion of the vane, if any, and record the angle, relative to uB,where motion ceases. Increase the speed slightly and repeat thetest; continue in this manner
36、 until a speed is reached where thevane moves at least 1 toward uB.7.2.3 Using the speed determined in 7.2.2, displace the vaneby 10 and release it five consecutive times to one side of uB,observing and recording the angle where it stops each time.Repeat five times with the displacements to the othe
37、r side ofuB.7.2.4 If all ten repetitions result in the vane moving at least1 toward uB, the wind speed may be used as the startingthreshold in accordance with this test method. The average ofthe absolute angular displacement from uBon each side shouldbe calculated. The higher of the two is the accur
38、acy at thethreshold speed.7.3 Delay Distance:7.3.1 Set the wind tunnel speed at 5 m/s. Displace the vane10 from uBand release it by the method in 7.2.1. Take fourmore samples in the same direction and five samples in theopposite direction.7.3.2 Repeat the procedure of 7.3.1 with the wind tunnelspeed
39、 set a 10 m/s.7.3.3 If desired, repeat the procedure of 7.3.1 at other windtunnel speeds.7.3.4 For the ten samples taken at a tunnel speed, measurethe time from release to crossing 5 from uB(or 50 % of theactual release displacement, a nominal 10) for each of thesamples. Convert each of these times
40、to a distance by multi-plying by the tunnel speed. Average the distances to arrive at adelay distance for this speed.7.3.5 Repeat the procedure of 7.3.4 for ten samples taken ateach tunnel speed considered.7.3.6 Average the delay distances found in 7.3.4 and 7.3.5.The delay distance for each speed s
41、hall be within 10 % of thisaverage.NOTE 1If the delay distance for any speed considered is outside610 % of the average, a delay distance for the vane cannot be specified.7.4 Overshoot Ratio:7.4.1 For each of the samples recorded for 7.3, read themaximum angular excursion on the opposite side of uBfr
42、omthe initial displacement.7.4.2 Form a ratio by dividing each angular excursionobtained in 7.4.1 by the corresponding angular differencebetween the release angle and uB. Average these ratios to arriveat the overshoot ratio for the vane.8. Precision and Bias8.1 The accuracy in measurement of the win
43、d tunnel speedlimits the accuracy of this test method. An accuracy of 0.1 m/sis required. This shall be documented at the wind tunnel facilityand be related to measurements at NIST5by a report on thetransfer standard that carries the same accuracy limit.8.2 PrecisionUsing this equipment and procedur
44、e, anestimate of the precision of the test method follows:8.2.1 Starting ThresholdThe precision of this test methodis 0.1 m/s or better.8.2.2 Delay DistanceThe precision of this test method is0.1 m or better.8.2.3 Overshoot RatioThe precision of this test method is0.02 or better.8.3 Bias:8.3.1 Start
45、ing ThresholdThe bias of this test method is nogreater than 0.15 m/s.8.3.2 Delay DistanceThe bias of this test method is nogreater than 0.15 m.8.3.3 Overshoot RatioThe bias of this test method is nogreater than 0.05.9. Keywords9.1 damping ratio; delay distance; overshoot ratio; startingthreshold; wi
46、nd vaneD 5366 96 (2002)e13REFERENCES(1) Finkelstein, P. L., “Measuring the Dynamic Performance of WindVanes,” Journal of Applied Meteorology, Vol. 20, 1981, pp. 588594.(2) MacCready, Jr., P. B., and Jex, H. R., “Response Characteristics andMeteorological Utilization of Propeller and Vane Wind Sensor
47、s,”Journal of Applied Meteorology, Vol 3, No. 2, 1964, p. 185.(3) “Determining Meteorological Information at Nuclear Power Facili-ties.” ANSI/ANS-3.11, American Nuclear Society, 2002 La GrangePark, IL.(4) Safety Theories, “Atmospheric Dispersion in Nuclear Power PlantSitingA Safety Guide,” Internati
48、onal Atomic Energy Agency, No.50-FG-F3, 1980.(5) U.S. Environmental Protection Agency, “Ambient Monitoring Guide-lines for Prevention of Significant Deterioration (PSD),” EPA-450/4-87-007, U.S. Environmental Protection Agency, 1987.(6) Pope, A., and Harper, J. J., Low-Speed Wind Tunnel Testing, John
49、Wiley and Sons, New York, 1966, pp. 85125; pp. 406432.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not
