A new criterion for end-conduction effects in hot-wire anemometry
نویسندگان
چکیده
The effect of end conduction on constant temperature hot-wire anemometry was studied. A new parameter, = ( /d)√4a(kf /k)Nu, is proposed to describe the significance of end conduction more comprehensively than the commonly used length-to-diameter ratio /d, in that it allows for material property variations, resistance ratio and Reynolds number effects. Numerical and experimental data are used to show that improves the correlation of the attenuation of measured turbulence fluctuations, and it is found that > 14 is required to avoid such effects.
منابع مشابه
A calibration technique to correct sensor drift issues in hot-wire anemometry
Accurate calibration is imperative to obtain reliable flow measurements using hot-wire anemometry. Calibration errors owing to temperature drift, wire degradation, changes in ambient conditions etc can lead to substantial uncertainties in hot-wire measurements. A new calibration procedure is implemented here to account for most forms of drift that are typically encountered during high quality f...
متن کاملThe response of hot wires in high Reynolds-number turbulent pipe flow
Issues concerning the accuracy of hot-wire measurements in turbulent pipe flow are addressed for pipe Reynolds numbers up to 6 × 106 and hot-wire Reynolds numbers up to Rew ≈ 250. These include the optimization of spatial and temporal resolution and the associated feature of signal-to-noise ratio. Very high wire Reynolds numbers enable the use of wires with reduced length-to-diameter ratios com...
متن کاملOn the use of hot-wire anemometry in pulsating flows. A comment on ‘A critical review on advanced velocity measurement techniques in pulsating flows’
In their recent topical review, Nabavi and Siddiqui (Meas. Sci. Technol. 2010 21 042002) recommended the use of hot-wire anemometry for velocity measurements in pulsating flows, especially at high frequency. This recommendation is misleading. The procedures invoked by these authors are valid only for small-amplitude fluctuations, which are of little interest for pulsating flows. When large-ampl...
متن کاملAlgorithm to optimize transient hot-wire thermal property measurement.
The transient hot-wire method has been widely used to measure the thermal conductivity of fluids. The ideal working equation is based on the solution of the transient heat conduction equation for an infinite linear heat source assuming no natural convection or thermal end effects. In practice, the assumptions inherent in the model are only valid for a portion of the measurement time. In this st...
متن کاملExperimental Investigation of wake on an elliptic cylinder in the presence of tripping wire
In this research, the behavior and characteristics of the wake of flow in an elliptic cylinder with zero angle of attack in the presence of a tripping wire were investigated experimentally. For this purpose, the used an Aluminum cylinder with an elliptical cross section of the major and minor axis of 42.4 mm and 21.2 mm, respectively, and of the height of 390 mm. The cylinder model was examined...
متن کامل