scispace - formally typeset
Search or ask a question
Journal ArticleDOI

A Sonic Velometer

01 Sep 1974-IEEE Transactions on Instrumentation and Measurement (IEEE)-Vol. 23, Iss: 3, pp 203-210
TL;DR: In this article, the transit times of sound pulses in air have been measured using phase-locking techniques and a wind-velocity resolution of 0.13 m/s has been obtained.
Abstract: Wind-velocity measurement at remote winter mountain sites is hampered by icing of the moving parts of the measuring device and by restrictions on the amount of electrical power which is available. A sonic velometer which determines the wind velocity by measuring the transit times of sound pulses in air and has no moving parts has been developed. The sound pulse transit times are measured accurately through the use of phase-locking techniques. Circuit construction is exclusively solid state, with integrated circuits used for several functions. The device exhibits an uncertainty of 0.05 percent in the determination of the pulse-transit times yielding a wind-velocity resolution capability of 0.13 m/s. The velometer has been tested over a dynamic range of 5 m/s.
Citations
More filters
PatentDOI
TL;DR: In this article, an acoustic current meter with two transducers aimed at an acoustic mirror is described, where the reflected acoustic signal from each transducer impinges upon the opposite transducers.
Abstract: An acoustic current meter in which two channels have acoustic paths oriented at right angles to each other to measure orthogonal components of a current velocity. Each channel includes two transducers aimed at an acoustic mirror so that the reflected acoustic signal from each transducer impinges upon the opposite transducer. Periodically, a burst of high frequency acoustic energy is simultaneous emitted by each transducer. A current flowing produces a relative phase shift between the received signals representative of the current velocity. The output signal produced by each of the transducers is mixed with a common reference signal to provide two, low frequency, beat frequency signals having a phase difference proportional to the current velocity. Due to the reduction in frequency, the phase shift is expanded in time with respect to the phase shift of the acoustic signals and may be easily measured.

31 citations

Patent
19 Jul 1979
TL;DR: In this article, two ultrasonic transducers are arranged to produce mutually perpendicular ultrasonic beams, and a computer is used to compute wind speed and direction from the frequency or phase relationships.
Abstract: Fluid flow measuring apparatus comprises two ultrasonic transducers (1, 2) between which an ultrasonic energy beam is transmitted through the fluid The beam is frequency modulated (4, 5) by an audio signal, and the relationship between the frequency or phase of the received modulation signal (6, 7, 8) and that of the transmitted modulation signal gives a measure (10) of the speed of flow of the fluid Beams of ultrasonic energy are preferably fed in two mutually opposite directions, for example by switching (3) the transducers to act alternately as transmitter and receiver, and the measurement is computed from the two relationships An anemometer (FIG 7) comprises two such systems arranged to produce mutually perpendicular ultrasonic beams, and a computer (25) to compute wind speed (28) and direction (29) from the frequency or phase relationships

29 citations

Journal ArticleDOI
TL;DR: This work reviews ultrasonic measurement of fluid flow with emphasis on ultrasonic pneumotachometers (UPTM's) and UPTM's, and presents four principle types: time of flight, sing around, phase shift, and phase-locked frequency shift.
Abstract: We review ultrasonic measurement of fluid flow with emphasis on ultrasonic pneumotachometers (UPTM's). For PTM's we discuss specifications such as dynamic range, resistance, and frequency response. We review fluid flow principles and point out the problems of nonultrasonic PTM's For UPTM's we describe transducer construction, attenuation versus frequency, reflection at interfaces, and acoustic field patterns. We present four principle types: 1) time of flight, 2) sing around, 3) phase shift, and 4) phase-locked frequency shift. For each, we detail principles, advantages, disadvantages, and potential for future development.

19 citations

Patent
28 May 1981
TL;DR: In this paper, an antenna network consisting of a multiplicity of receiving antennas laid out in the pattern of a lattice is used to detect the position where the spot due to the convergence of the reflected radio waves is formed with the maximum intensity.
Abstract: An acoustic wave source and a radio wave source are installed close to each other on the ground. When an acoustic wave pulse is transmitted vertically into the atmosphere by the acoustic wave source, spherical wavefronts formed in the atmosphere by the acoustic wave are propagated upwardly at the velocity of sound. When a continuous radio wave is transmitted from the radio wave source toward the spherical wavefronts, it is reflected by the wavefronts and the reflected radio waves are converged to form a focusing spot on the ground. The position where the spot due to the convergence of the reflected radio waves is formed with the maximum intensity is detected by means of an antenna network formed of a multiplicity of receiving antennas laid out in the pattern of a lattice. The time-course change of such positions of the spots is traced to realize remote measurement of the height distribution of wind direction and speed in the atmosphere under surveillance.

17 citations

Patent
21 Mar 1979
TL;DR: An acoustic fluid velocity measuring system includes mutually perpendicular arms disposed in the direction of the rectangular components of the fluid velocity, with each arm supporting two transmitting and two receiving electro-acoustic transducers.
Abstract: An acoustic fluid velocity measuring system includes mutually perpendicular arms disposed in the direction of the rectangular components of the fluid velocity, with each arm supporting two transmitting and two receiving electro-acoustic transducers. Pulses of ultrasonic energy are transmitted and received in and against the direction of fluid flow. The transducers in each arm are arranged in separate electrical loops, each of which provides an output at a different frequency. The frequencies are compared to measure fluid speed and direction which appear on a digital display. The measurements are independent of ambient temperature and the transducers are heated so that the system operates under ice forming meteorological conditions.

15 citations