A study of the constant-temperature hot-wire anemometer

The conventional ‘bridge-feedback amplifier’ constant-temperature hot-wire anemometer is analysed to determine its static and dynamic response. The effects of moderate feedback amplifier gain, bridge imbalance, stray bridge reactance, amplifier offset voltage, lack of common mode rejection, amplifier frequency response and departure from constant transconducture are included. The root loci of the system are mapped out and the consequences of the analysis are discussed from the viewpoint of both the operator and the designer.

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Determination and optimization of frequency response of constant temperature hot‐wire anemometers in supersonic flows

Review of Scientific Instruments ◽

10.1063/1.1136180 ◽

1980 ◽

Vol 51 (2) ◽

pp. 234-239 ◽

Cited By ~ 23

Author(s):

J. P. Bonnet ◽

T. Alziary de Roquefort

Keyword(s):

Frequency Response ◽

Constant Temperature ◽

Supersonic Flows ◽

Hot Wire

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Comments on ’’Determination and optimization of frequency response of constant temperature hot‐wire anemometers in supersonic flows’’

Review of Scientific Instruments ◽

10.1063/1.1136294 ◽

1980 ◽

Vol 51 (6) ◽

pp. 857-857

Author(s):

P. Freymuth

Keyword(s):

Frequency Response ◽

Constant Temperature ◽

Supersonic Flows ◽

Hot Wire

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

Journal of Fluid Mechanics ◽

10.1017/s0022112075000602 ◽

1975 ◽

Vol 67 (4) ◽

pp. 769-786 ◽

Cited By ~ 30

Author(s):

N. B. Wood

Keyword(s):

Frequency Response ◽

Constant Temperature ◽

Hot Wire ◽

Flow Conditions ◽

Mean Flow ◽

Quantitative Results ◽

The Mean ◽

Constant Temperature Anemometer ◽

And Control ◽

Simultaneous Variation

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.

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