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A method for determination and control of the frequency response of the constant-temperature hot-wire anemometer

Published online by Cambridge University Press:  29 March 2006

N. B. Wood
N. B. Wood
Affiliation:
Central Electricity Research Laboratories, Leatherhead, Surrey, England
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Abstract

The theory of the constant-temperature anemometer has been extended in order to obtain quantitative results for the frequency response. A simple electrical test against which to check the theory has been devised, and the validity of the anemometer equations is demonstrated. Important differences in design philo-sophies and modes of operation are indicated, and results are presented for a design in which high d.c. gain is employed in the servo amplifier. The square-wave response is briefly investigated, and it is concluded that commonly used criteria for determining the frequency response from it should be treated with caution.

To measure fluctuations with a hot-wire anemometer in flows containing both velocity and temperature perturbations, the hot wire must be operated at more than one temperature. Variation of the mean wire temperature causes, in general, a variation in the frequency response, as does variation of the mean flow conditions. It is shown that, by simultaneous variation of the gain of the servo amplifier in the anemometer, the frequency response may be held nearly constant over a useful range of both overheat and flow conditions.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 67 , Issue 4 , 25 February 1975 , pp. 769 - 786
Copyright
© 1975 Cambridge University Press

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References

Davis, M. R. 1970 The dynamic response of constant resistance anemometers. J. Phys. E, Sci. Instrum., 3, 15–20.Google Scholar
Davis, M. R. & Davies, P. O.A. L. 1968 The physical characteristics of hot-wire anemometers. University of Southampton, I.S. V.R. Tech. Rep. no. 2.Google Scholar
Freymuth, P. 1967 Feedback control theory for constant-temperature hot-wire anemometers. Rev. Sci. Instrum., 38, 677–681.Google Scholar
Grant, H. P. 1968 Measuring the frequency response of constant temperature and constant current hot-wire systems. In Advances in Hot-wire Anenzometry (ed. W. R. Melnik & J. R. Weske), pp. 251–257. University of Maryland.
Grant, H. P. & Kronauer, R. E. 1962 Fundamentals of hot-wire anemometry. Symp. On Measurement in Unsteady Plow, pp. 44–53. A.S.M.E.
Horowitz, I. 1963 Synthesis of Feedback Systems. Academic.
Janssen, J. M. L., Ensing, L. & Van Erp, J. B. 1959 A constant-temperature-operation hot-wire anemometer. Proc. I.R.E., 47, 555–567.Google Scholar
Kidron, I. 1966 Application of modulated electromagnetic waves for measurement of the frequency response of heat transfer transducers. DISA Inf. no 4, 25–29.Google Scholar
Kovasznay, L. S. G. 1950 The hot-wire anemometer in supersonic flow. J. Atro. Sci., 17, 565–572.Google Scholar
Nielsen, P. E. & Rasmussen, C. G. 1966 Measurement of amplitude and phase characteristics. DISA Inf. no. 4, 17–23.Google Scholar
Ossofsey, E. 1948 Constant temperature operation of the hot-wire anemometer at high frequency. Rev. Sci. Instrum., 19, 881–889.Google Scholar
Perry, A. E. & Morrison, G. L. 1971a A study of the constant-temperature hot-wire anemometer. J. Fluid Mech., 47, 577–599.Google Scholar
Perry, A. E. & Morrison, G. L. 1971b Vibration of hot-wire anemometer filaments. J. Fluid Mech., 50, 815–825.Google Scholar
Roberts, J. B. 1973 On the correction of hot wire turbulence measurements for spatial resolution errors. Aero. J., 77, 406–412.Google Scholar
Starkey, B. J. 1958 Laplace Transforms f o r Electrical Engineers. London: Iliffe.
Tennekes, H. & Mccall, P. K. 1971 Measurements of temperature and velocity fluctuations with two constant-temperature hot-wire anemometers. Am. Phya. Xoc., Div. Fluid Mech., Ann. Meeting, paper DB12.Google Scholar
Weske, J. R. 1943 A hot-wire circuit with very small time lag. N.A.C.A. Tech. Note, no. 881.Google Scholar
Wood, N. B. 1973 Flow unsteadiness and turbulence measurements in the low pressure cylinder of a 500MW steam turbine. Inst. Mech. Engrs Conf. Publ. no. 3.Google Scholar