1、Designation: D5366 96 (Reapproved 2017)Standard Test Method forDetermining the Dynamic Performance of a Wind Vane1This standard is issued under the fixed designation D5366; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the startingthreshold, delay distance, and overshoot ratio of a wind va
3、nefrom 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 a wind vane and itsassociated position-to-output transducer in wind tunnel flow.Use of
4、 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 systems andthe two environments.1.3 The values stated in SI units are to be regarded ass
5、tandard. No other units of measurement are included in thisstandard.1.4 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 a
6、pplica-bility of regulatory limitations prior to use.1.5 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
7、 by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1356 Terminology Relating to Sampling and Analysis ofAtmospheres3. Terminology3.1 For terms that are not defined herein, refer to Terminol-ogy D1356.3.2 Definitions:3.2.1 delay dis
8、tance (D)the distance the air flows past awind vane during the time it takes the vane to return to 50 %of the initial displacement.3.2.2 overshoot (n)the amplitude of a deflection of awind vane as it oscillates about Bafter release from an initialdisplacement.3.2.3 overshoot ratio ()the ratio of two
9、 successiveovershoots, as expressed by the equation: 5 n11!/n(1)where nand (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, the initial re-lease point (that is, the n = 0 deflection) and the
10、first deflec-tion after release (n = 1) are used in determining the over-shoot ratio.3.2.4 starting threshold (Uo)the lowest speed at which thevane can be observed or measured moving from a 10 offset ina wind tunnel.3.3 Symbols:D (m) delay distanceUo(m/s) starting threshold (none) overshoot ratio (n
11、one) damping ratiod(m) damped natural wavelengthn(degrees) overshoot; maximum angular excursiono(degrees) reference directionB(degrees) vane equilibrium positionB o(degrees) dynamic vane bias3.4 Calculated or Estimated Values:3.4.1 damping ratio ()calculated from the overshootratio (1, 2).3 5ln1/!21
12、ln1/!#2!0.5(2)1This test method is under the jurisdiction of ASTM Committee D22 on AirQuality and is the direct responsibility of Subcommittee D22.11 on Meteorology.Current edition approved March 15, 2017. Published March 2017. Originallyapproved in 1993. Last previous edition approved in 2011 as D5
13、366 96 (2011).DOI: 10.1520/D5366-96R17.2For referenced ASTM standards, 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.3The boldface numbers
14、in parentheses refer to the list of references at the end ofthis standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardiza
15、tion established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.4.2 damped natural wavelength (d)at sea level in theU.S. Standard Atmosphere, damped natural
16、wavelength isrelated to delay distance and damping ratio by the empiricalexpression (1, 2).3d5D6.0 2 2.4!1 2 2!0.5(3)4. Summary of Test Method4.1 Reference Direction (o, degrees) is the indicated angu-lar position of the vane when aligned along the centerline of thewind tunnel.4.2 Vane Equilibrium P
17、osition (B, degrees) is the finalresting position of the vane after motion in response to aninitial displacement. Ideally, B= o.4.3 Dynamic Vane Bias (B o, degrees) is the displace-ment of the vane from the wind tunnel centerline at 5 m/s. Thismeasurement will identify wind vanes with unbalanced aer
18、o-dynamic response because of damage (for example, bent tail)or poor design.4.4 Starting Threshold (Uo, m/s) is determined by observingor measuring the lowest speed at which the vane, released froma 10 offset position in a wind tunnel, moves toward B.Movement must be distinguishable from vibration.4
19、.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 displacement from 10 off B. This time in secondsis converted to delay distance by multiplying by the windtunnel speed
20、 in metres per second. Tests shall include an equalnumber of displacements to each side of B.4.6 Overshoot Ratio () may be determined at the sametime as the delay distance. The maximum angular excursion onthe opposite side of Bfrom the initial 10 displacementfromBis measured. This value is divided b
21、y the initialdisplacement to obtain .5. Significance and Use5.1 This test method will provide a standard for comparisonof wind vanes of different types. Specifications by regulatoryagencies and industrial societies (3-5) have stipulated perfor-mance values. This test method provides an unambiguousme
22、thod for measuring starting threshold, delay distance, andovershoot ratio.6. Apparatus6.1 Wind Tunnel (6):6.1.1 SizeThe wind tunnel shall be large enough so thatthe total projected area of supports, sensor apparatus, and thevane in its displaced position is less than 5 % of the cross-sectional area
23、of its test section.6.1.2 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 maintain the flow ratewithin 60.2 m/s.6.1.3 Turbulence and SwirlAcross the volume to be oc-cupied by the vane, the flow profile
24、shall vary by no more than1 % about the mean speed and shall exhibit a turbulence of lessthan 1 %. (Warning Swirl in the wind tunnel may influencestarting threshold measurements. Variations in the measure-ment of Ba low speeds likely indicate the existence of swirl.)6.1.4 CalibrationThe mean flow ra
25、te 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 the National Bu-reau of Standards)4or by a fundamental physical method.6.1.4.1 Speeds below 2 m/s for threshold dete
26、rminationshall 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 puffsbetween two points separated by a known distance.6.1.5 EnvironmentThe temperature and pressure of theenvironment wit
27、hin 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 independent measurements of startingthreshold, delay distance, and overshoot ratio since thesevalues are density dependent.6.2
28、 Measuring System:6.2.1 DirectionThe resolution of the wind vane position-tooutput transducer limits the resolution of the measure-ments.The accuracy of the positiontooutput conversion shallbe within 60.1. (WarningAvoid potentiometer dead spotsor crossover positions while performing these procedures
29、.)6.2.2 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. For 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
30、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.6.3 Signal ConditioningCare shall be taken to avoidelectronic circuits in signal conditioning and recording devicesthat adversely affect the
31、apparent vane performance.(WarningTime constants in signal conditioning and record-ing devices shall be less than 0.01 s.)6.4 Recording TechniquesThe measuring or recordingsystem shall represent the 10 displacement on each side of Bwith a resolution of 0.2. One simple technique is to use afast-respo
32、nse recorder (flat to 4060 Hz or better) with enoughgain so that a vane can be oriented in the wind tunnel with Brepresented at mid-scale, and 610 of vane displacementtraversing the full span of the recorder.6.4.1 The recorder shall have a fast chart speed of 50 mm/sor more. An alternative is to use
33、 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 acceptable. Oscilloscopes with memoryand hard copy capability may also be used.6.4.2 Digital recording and data reduction system
34、s aresatisfactory if the sampling rate is at least 100 per second.4Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.D5366 96 (2017)27. Sampling7.1 Starting ThresholdTen consecutive tests at the samespeed m
35、eeting the test method requirement, five in eachdirection from B, are required for a valid starting thresholdmeasurement.7.2 Delay Distance and Overshoot RatioThe arithmeticmean of ten tests, five in each direction from B, is required fora valid measurement at each speed. The results of measure-ment
36、s at two or more speeds shall be averaged to a single valuefor delay distance and a single value for overshoot ratio.8. Procedure8.1 Dynamic Vane Bias:8.1.1 Set vane at tunnel centerline with no flow in the windtunnel.8.1.2 Adjust the wind tunnel to give a flow of 5 m/s.8.1.3 Measure the equilibrium
37、 vane position (B) relative tothe tunnel centerline (o). The angular difference, B ois thedynamic vane bias.8.1.4 A dynamic vane bias greater than 1 indicates poordesign or a problem with the vane. Appropriate correctionsshall be made before continuing.8.2 Starting Threshold:8.2.1 Provide a mechanic
38、al method for holding and releas-ing the vane at 10 6 1 from B. With no flow in the windtunnel, verify that the vane moves by no more than 60.5 whenthe release mechanism is activated.8.2.2 Adjust the wind tunnel to a speed expected to be lowerthan the starting threshold. Displace the vane by 10 and
39、thenrelease it by the procedure described in 8.2.1. Observe themotion of the vane, if any, and record the angle, relative to B,where motion ceases. Increase the speed slightly and repeat thetest; continue in this manner until a speed is reached where thevane moves at least 1 toward B.8.2.3 Using the
40、 speed determined in 8.2.2, displace the vaneby 10 and release it five consecutive times to one side of B,observing and recording the angle where it stops each time.Repeat five times with the displacements to the other side ofB.8.2.4 If all ten repetitions result in the vane moving at least1 toward
41、B, the wind speed may be used as the startingthreshold in accordance with this test method. The average ofthe absolute angular displacement from Bon each side shouldbe calculated. The higher of the two is the accuracy at thethreshold speed.8.3 Delay Distance:8.3.1 Set the wind tunnel speed at 5 m/s.
42、 Displace the vane10 from Band release it by the method in 8.2.1. Take fourmore samples in the same direction and five samples in theopposite direction.8.3.2 Repeat the procedure of 8.3.1 with the wind tunnelspeed set a 10 m/s.8.3.3 If desired, repeat the procedure of 8.3.1 at other windtunnel speed
43、s.8.3.4 For the ten samples taken at a tunnel speed, measurethe time from release to crossing 5 from B(or 50 % of theactual release displacement, a nominal 10) for each of thesamples. Convert each of these times to a distance by multi-plying by the tunnel speed. Average the distances to arrive at ad
44、elay distance for this speed.8.3.5 Repeat the procedure of 8.3.4 for ten samples taken ateach tunnel speed considered.8.3.6 Average the delay distances found in 8.3.4 and 8.3.5.The delay distance for each speed shall be within 10 % of thisaverage.NOTE 1If the delay distance for any speed considered
45、is outside610 % of the average, a delay distance for the vane cannot be specified.8.4 Overshoot Ratio:8.4.1 For each of the samples recorded for 8.3, read themaximum angular excursion on the opposite side of Bfromthe initial displacement.8.4.2 Form a ratio by dividing each angular excursionobtained
46、in 8.4.1 by the corresponding angular differencebetween the release angle and B.Average these ratios to arriveat the overshoot ratio for the vane.9. Precision and Bias9.1 The accuracy in measurement of the wind tunnel speedlimits the accuracy of this test method. An accuracy of 0.1 m/sis required.Th
47、is 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.9.2 PrecisionUsing this equipment and procedure, anestimate of the precision of the test method follows:9.2.1 Starting ThresholdThe precis
48、ion of this test methodis 0.1 m/s or better.9.2.2 Delay DistanceThe precision of this test method is0.1 m or better.9.2.3 Overshoot RatioThe precision of this test method is0.02 or better.9.3 Bias:9.3.1 Starting ThresholdThe bias of this test method is nogreater than 0.15 m/s.9.3.2 Delay DistanceThe
49、 bias of this test method is nogreater than 0.15 m.9.3.3 Overshoot RatioThe bias of this test method is nogreater than 0.05.10. Keywords10.1 damping ratio; delay distance; overshoot ratio; startingthreshold; wind vaneD5366 96 (2017)3REFERENCES(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 Utili
