1、DRAFT FOR DEVELOPMENTDD ISO/TS 24154:2005Hydrometry Measuring river velocity and discharge with acoustic Doppler profilersICS 17.120.20g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38
2、g50g51g60g53g44g42g43g55g3g47g36g58DD ISO/TS 24154:2005This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 31 March 2006 BSI 2006ISBN 0 580 48073 9National forewordThis Draft for Development reproduces verbatim ISO/TS 24154:2005.This publica
3、tion is not to be regarded as a British Standard.It is being issued in the Draft for Development series of publications and is of a provisional nature because the technology is still maturing though the Subcommittee felt that there was a need to have a document available to assist users, manufacture
4、rs and other stakeholders. It should be applied on a provisional basis, so that information and experience of its practical application may be obtained.Comments arising from the use of this Draft for Development are requested so that UK experience can be reported to the international organization re
5、sponsible for the Technical Specification. A review of this publication will be initiated not later than 3 years after its publication by the international organization so that a decision can be taken on its status at the end of its 3-year life. Notification of the start of the review period will be
6、 made in an announcement in the appropriate issue of Update Standards.According to the replies received by the end of the review period, the responsible BSI Committee will decide whether to support the conversion into an international standard, to extend the life of the Technical Specification for a
7、nother 3 years or to withdraw it. Comments should be sent in writing to the Secretary of BSI Subcommittee CPI/113/5, Measuring instruments and equipment, at British Standards House, 389 Chiswick High Road, London W4 4AL, giving the document reference and clause number and proposing, where possible,
8、an appropriate revision of the text.A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section enti
9、tled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Summary of
10、pagesThis document comprises a front cover, an inside front cover, the ISO/TS title page, pages ii to iv, pages 1 to 10, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. D
11、ate CommentsReference numberISO/TS 24154:2005(E)TECHNICAL SPECIFICATION ISO/TS24154First edition2005-11-15Hydrometry Measuring river velocity and discharge with acoustic Doppler profilers Hydromtrie Mesure de la vitesse et du dbit des rivires au moyen de profileurs effet Doppler DD ISO/TS 24154:2005
12、ii iiiContents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Background . 2 5 Principles of operation. 2 6 Application of acoustic Doppler profilers to measurement of river discharge 3 6.1 Instrumentation and equipment requirements 3 6.2 Making the measurement.
13、 4 6.3 Computing the measurement 4 7 Factors affecting operation and accuracy . 6 7.1 Characteristics of the acoustic Doppler profiler . 7 7.1.1 Transducers or beams . 7 7.1.2 Size and frequency . 7 7.2 River and channel characteristics 7 7.3 Operator training and experience . 8 8 Verification 8 9 C
14、onstruction 8 10 Maintenance 9 Bibliography . 10 DD ISO/TS 24154:2005iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO tech
15、nical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
16、 with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft I
17、nternational Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In other circumstances, particularly when there is an urgent market requirement
18、for such documents, a technical committee may decide to publish other types of normative document: an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for publication if it is approved by more than 50 % of the me
19、mbers of the parent committee casting a vote; an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a vote. An ISO/PAS or ISO/TS is reviewed after t
20、hree years in order to decide whether it will be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an International
21、Standard or be withdrawn. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO/TS 24154 was prepared by Technical Committee ISO/TC 113, Hydrometry, Su
22、bcommittee SC 5, Instruments, equipment and data management. DD ISO/TS 24154:20051Hydrometry Measuring river velocity and discharge with acoustic Doppler profilers 1 Scope Acoustic Doppler profilers are instruments and software packages used to measure water velocity, channel bathymetry, and river d
23、ischarge. This Technical Specification gives the principles of operation, construction, maintenance and application of acoustic Doppler profilers to the measurement of velocity and discharge, and discusses calibration and verification issues. It is applicable to open-channel flow measurements with a
24、n instrument mounted on a moving vessel. It is not applicable to measurement of liquid flow in small channels or partly-filled pipes using a single Doppler-based flowmeter at a fixed point in the cross section. 2 Normative references The following referenced documents are indispensable for the appli
25、cation of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 772, Hydrometric determinations Vocabulary and symbols 3 Terms and definitions For the purposes of this documen
26、t, the terms and definitions given in ISO 772 and the following apply. 3.1 Doppler shift general change in frequency of a sound source as it approaches and recedes from an observer 3.2 Doppler shift acoustic Doppler instruments difference or shift in frequency of emitted sound waves as they are refl
27、ected back from moving particles in the water 3.3 Doppler-based flowmeter class of instruments that uses the principle of Doppler shift to compute water velocity and discharge NOTE These instruments can be deployed at a fixed point in a cross section or on a moving vessel. 3.4 acoustic Doppler profi
28、ler ADP instrument that uses the principle of Doppler shift to compute water velocity and discharge NOTE The instrument is usually mounted on a vessel that transits across a river channel perpendicular to flow. DD ISO/TS 24154:20052 3.5 ping series of acoustic pulses of a given frequency transmitted
29、 by an acoustic Doppler instrument 3.6 ensemble collection of pings NOTE Because the measurement results from a single ping have a relatively high error, the results of more than one ping are usually averaged to obtain a single measurement. 3.7 transect collection of ensembles from a single pass acr
30、oss a river, lake, or estuary NOTE When measuring streamflow with an acoustic Doppler profiler, one transect may constitute a single measurement of discharge. 4 Background Acoustic Doppler instruments for measuring water velocity have been in use for about 25 years, primarily in the study of ocean c
31、urrents and estuaries. In the late 1980s, acoustic Doppler instruments began to be used to make velocity measurements from a moving vessel 3, 13. The early instruments were narrow-band acoustic Doppler instruments that required deep water (! 3,4 m), which limited their use to deep rivers and estuari
32、es. In 1992, a more advanced acoustic Doppler instrument, known as a Broadband Acoustic Doppler Current Profiler, was developed that could be used to measure velocities in shallow waters (as shallow as 1,0 m) with a high degree of vertical resolution (0,10 m). Throughout the 1990s, acoustic Doppler
33、profilers were continually developed and enhanced by several manufacturers. The instruments have been refined from very cumbersome and heavy units that were 1 m in length and weighing as much as 50 kg to compact and light units as small as 14 cm long and weighing 7 kg. The acoustic Doppler profilers
34、 now include advanced acoustic instrumentation designed specifically for use in rivers and software for real-time and post-processing of river velocity and discharge measurements. Acoustic Doppler profilers (3.3) are routinely used to measure discharge in estuaries, rivers, and canals where conventi
35、onal discharge-measurement techniques are either very expensive or impossible due to stratification of the flow. They are also routinely used to measure discharge in large rivers, in part because of cost savings and reduced uncertainties due to smaller changes in discharge during the measurement. 5
36、Principles of operation In moving vessel deployments, the acoustic Doppler instrument is mounted to a vessel (usually a motorized boat) that moves across the water body perpendicular to the current being measured. Water velocities are measured by the acoustic Doppler instrument, which transmits acou
37、stic pulses along three or four beams at a constant frequency between 75 kHz to 3 000 kHz. The beams are positioned at precise horizontal angles from each other (120 for 3-beam instruments and 90 for 4-beam instruments (see Figure 1). The beams are directed at a known angle from vertical, typically
38、20 or 30. The instrument detects and processes echoes throughout the water column along each beam. DD ISO/TS 24154:20053Figure 1 Schematic diagram of an acoustic Doppler instrument with a 4-beam configuration The difference in frequency (shift) between successive echoes is proportional to the relati
39、ve velocity between the acoustic Doppler instrument and suspended material in the water that reflects the pulses back to the instrument. This frequency shift is known as the Doppler effect. The acoustic Doppler instrument uses the Doppler effect to compute a water-velocity component along each beam,
40、 and the system software computes water velocity in three directions using trigonometric relations. Velocities are determined at preset intervals called bins along the acoustic path. The instrument setup parameters can be adjusted to optimize the system for the river cross section being measured. Th
41、ese parameters include the depth cell size, the number of depth cells, the number of pings, and velocity reference commands. The water-velocity measurements incorporate both the true water velocity and the boat velocity. The boat velocity can be measured by using the Doppler shift of separate acoust
42、ic pulses reflected from the river bottom. This technique, referred to as bottom tracking, is commonly used; it was first used with early sonar to measure the speed of a moving vessel. In addition to measuring boat velocity, the depth of the river is estimated from the amplitude of the bottom-track
43、echoes (echoes returned from the bottom). Real-time differential global-positioning systems (DGPS) provide an alternative technique for measuring the boat velocity. When the acoustic Doppler instrument is being used to measure discharge, it transmits a series of acoustic pulses known as pings (3.5).
44、 Pings for measuring water velocities are known as water pings, and pings for measuring the boat velocity are known as bottom-tracking pings. Normally, water pings and bottom-tracking pings are interleaved during transmission. A group of these interleaved water and bottom-tracking pings are referred
45、 to as an ensemble (3.6). The user sets the number of water and bottom-tracking pings per ensemble. An ensemble is analogous to one vertical in a conventional discharge measurement. For example, a typical ensemble is composed of a combination of water pings and bottom-tracking pings. The velocities
46、and depths measured for each ping are averaged to yield a single velocity profile and depth for each ensemble. In a conventional discharge measurement, velocity is measured at one point in the vertical when the depth is less than 0,8 m and two, three or five points in the vertical when the depth is
47、greater than 0,8 m. Depending on its characteristics, an acoustic Doppler profiler can measure velocities every 0,25 m in the vertical, so that one ensemble for a vertical 10 m deep may contain as many as 34 velocity measurements. 6 Application of acoustic Doppler profilers to measurement of river d
48、ischarge 6.1 Instrumentation and equipment requirements Making discharge measurements with acoustic Doppler profilers requires three main pieces of equipment: the acoustic instrument/transducer assembly, a vessel for mounting the instrument, and a portable computer. The instrument includes a pressur
49、e case that contains most of the electronics and a transducer assembly (see Figure 1). The transducer assembly may have a convex or concave assembly. The instruments come in a variety of sizes, beam configurations, and frequencies depending on the size and characteristics of rivers to be measured and the type of deployment. The small units are less than 30 cm tall and weigh about 7 kg; large units are 1 m tall and weigh 50 kg. DD ISO/TS 24154:20054 The type of acoustic Doppler profiler deployed depends on the river being measured. For small rivers, th
