Hot-wire calibration using vortex shedding

Ardekani, Mohammad Ali

doi:10.1016/j.measurement.2008.12.001

Cited by 13 publications

(6 citation statements)

References 5 publications

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“…Hence, taking all results with some tolerances into account, it is recommendable to determine the fundamental shedding frequency for 1 < / < 6 within 1 < | / | < 4, while the hot-wire voltage related to ∞ should be acquired at | / | > 5.5. These recommendations are also close to those given by Ardekani [21], who gave 2.2 < | / | < 2.9 for 3 < / < 6, for the regime bridging, the stable and irregular regimes, namely, 100 < Re < 430, in order to determine both and simultaneously. Nevertheless, it seems more appropriate to comply to the limits given here, due to the extended Rerange employed, in order to obtain an unbiased hot-wire voltage which is related to the voltage in the free stream.…”

Section: Placement Of the Hot-wire Probesupporting

confidence: 85%

“…For the calibration of hot wires at low velocities, several calibration techniques have been developed, such as modified calibration jets [8], the laminar pipe-flow method [9], the rotating disk method [10], methods exploring wall proximity effects [11,12], and a variety of methods utilizing a moving [13][14][15] or swinging probe in still air [16,17], as well as the vortex shedding method [12,[18][19][20][21]. In the present paper, we will focus on the vortex shedding calibration method, which has also been suggested in classical hot-wire literature, as, for example, in Perry [5] or Bruun [6].…”

Section: Introductionmentioning

confidence: 99%

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Hot-Wire Calibration at Low Velocities: Revisiting the Vortex Shedding Method

Sattarzadeh

Kalpakli

2013

Advances in Mechanical Engineering

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The necessity to calibrate hot-wire probes against a known velocity causes problems at low velocities, due to the inherent inaccuracy of pressure transducers at low differential pressures. The vortex shedding calibration method is in this respect a recommended technique to obtain calibration data at low velocities, due to its simplicity and accuracy. However, it has mainly been applied in a low and narrow Reynolds number range known as the laminar vortex shedding regime. Here, on the other hand, we propose to utilize the irregular vortex shedding regime and show where the probe needs to be placed with respect to the cylinder in order to obtain unambiguous calibration data.

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Section: Placement Of the Hot-wire Probesupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Hot-Wire Calibration at Low Velocities: Revisiting the Vortex Shedding Method

Sattarzadeh

Kalpakli

2013

Advances in Mechanical Engineering

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“…Placing the hot-wire sensor at a suitable location, the output voltage and Karman vortex frequency have been measured. [ 10 ] In this method, a cylindrical wire of 1 mm diameter is placed in the flow path, and the vortex shedding behind the wire is measured. Flow velocity is then calculated using the relation given by:[ 14 ]…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, different approaches such as moving the hot-wire probe in the fluid, or vortex shedding due to the presence of cylindrical wire in the air flow, may be used to obtain the calibration curve at low velocities. [ 8 – 10 ] Yet another alternative approach is to apply the law of conservation of mass, in which the pitot-tube is placed in the test section, and the hot-wire probe is located in a settling chamber. Although these methods can be used, in practice they may be difficult and time consuming to perform.…”

Section: Introductionmentioning

confidence: 99%

Extrapolation of calibration curve of hot-wire spirometer using a novel neural network based approach

2012

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Hot-wire spirometer is a kind of constant temperature anemometer (CTA). The working principle of CTA, used for the measurement of fluid velocity and flow turbulence, is based on convective heat transfer from a hot-wire sensor to a fluid being measured. The calibration curve of a CTA is nonlinear and cannot be easily extrapolated beyond its calibration range. Therefore, a method for extrapolation of CTA calibration curve will be of great practical application. In this paper, a novel approach based on the conventional neural network and self-organizing map (SOM) method has been proposed to extrapolate CTA calibration curve for measurement of velocity in the range 0.7-30 m/seconds. Results show that, using this approach for the extrapolation of the CTA calibration curve beyond its upper limit, the standard deviation is about –0.5%, which is acceptable in most cases. Moreover, this approach for the extrapolation of the CTA calibration curve below its lower limit produces standard deviation of about 4.5%, which is acceptable in spirometry applications. Finally, the standard deviation on the whole measurement range (0.7-30 m/s) is about 1.5%.

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“…The other technique required no additional instrument and was based on the dependence of vortex shedding frequency behind cylinders on the ow velocity. Di erent aspects of this technique may be found in investigations of Ardekani [10], Sattarzadeh et al [11], and Lee and Budwig [12]. A fully-developed laminar ow in a pipe was also used for calibration, as suggested by Lee and Budwig [12] and Yue and Malmstr om [13].…”

Section: Introductionmentioning

confidence: 99%

Hot-film/hot-wire anemometer calibration for low velocities using image processing

2019

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Calibration of hot-wire and hot-lm probes at low velocities is a di cult task because the dynamic pressure at these velocities is quite low and may not be easily measured. To solve this problem, substituent techniques have been presented in the literature that rely on other phenomena and utilize di erent hardware. This study described a simple and low-cost method which proposes moving the anemometer probe in the quiescent air (here by means of a swinging arm) and tracked this motion with a camera. After processing the images, the time history of the probe velocity was measured by numerical calculations. Calibration curve was, then, obtained without any predetermined relationship. Using a medium-speed video camera, which is often found in laboratories, would obviate the need for a position sensor and a complicated arm on which this sensor is mounted. This technique can be used for not only pendulums but also other means of moving probes in a quiescent medium.

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Hot-wire calibration using vortex shedding

Cited by 13 publications

References 5 publications

Hot-Wire Calibration at Low Velocities: Revisiting the Vortex Shedding Method

Hot-Wire Calibration at Low Velocities: Revisiting the Vortex Shedding Method

Extrapolation of calibration curve of hot-wire spirometer using a novel neural network based approach

Hot-film/hot-wire anemometer calibration for low velocities using image processing

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