Angular response of hot wire probes

Mare, Luca di; Jelly, Thomas O.; Day, IJ

doi:10.1088/1361-6501/aa5014

Cited by 6 publications

(5 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It means, that even if during measurements the probe is oriented exactly this same way as it was during calibration the results cannot be accurate if the flow is highly disturbed/turbulent or its main direction significantly deviates in time. This is one of a well-known restriction of the HWA technique and SN in particular [11,13,18,[22][23][24][25].…”

Section: Discussionmentioning

confidence: 99%

Experimental study of the flow field disturbance in the vicinity of single sensor hot-wire anemometer

Sobczyk¹

2018

EPJ Web Conf.

View full text Add to dashboard Cite

Abstract. Preliminary experimental study of the flow field disturbance in the vicinity of single sensor normal hot-wire anemometer (SN) probe was carried out. Regular 2D particle image velocimetry (PIV) setup equipped with micro lens and distance rings was applied to measurements of macroscopic flow around microscopic elements. Experimental results revealed complexity of the flow around the wire and its strong dependence on both -the velocity magnitude and the probe orientation in relation to freestream direction. Examination of the velocity fields in the vicinity of SN probe suggests that it may not be such a "point" measurement method as it is commonly assumed to be.

show abstract

Section: Discussionmentioning

confidence: 99%

Experimental study of the flow field disturbance in the vicinity of single sensor hot-wire anemometer

Sobczyk¹

2018

EPJ Web Conf.

View full text Add to dashboard Cite

show abstract

“…Usually, an exponential or power law fits adequately to the measurements, depending on the variables employed. Note that, in general, an angular factor may be included inside h(u), accounting for the relative orientation of the fluid flow and the wire [25,26]. In our case, this factor has also been omitted, since the dissipated power and the fraction of volume occupied by the fiber are both considerably small.…”

Section: Hot-wire Anemometrymentioning

confidence: 99%

Long-range distributed optical fiber hot-wire anemometer based on chirped-pulse ΦOTDR

et al. 2018

View full text Add to dashboard Cite

Abstract:We demonstrate a technique allowing to develop a fully distributed optical fiber hot-wire anemometer capable of reaching a wind speed uncertainty of ≈ ±0.15 m/s (±0.54 km/h) at only 60 mW/m of dissipated power in the sensing fiber, and within only four minutes of measurement time. This corresponds to similar uncertainty values than previous papers on distributed optical fiber anemometry but requires two orders of magnitude smaller dissipated power and covers at least one order of magnitude longer distance. This breakthrough is possible thanks to the extreme temperature sensitivity and single-shot performance of chirped-pulse phase-sensitive optical time domain reflectometry (ΦOTDR), together with the availability of metal-coated fibers. To achieve these results, a modulated current is fed through the metal coating of the fiber, causing a modulated temperature variation of the fiber core due to Joule effect. The amplitude of this temperature modulation is strongly dependent on the wind speed at which the fiber is subject. Continuous monitoring of the temperature modulation along the fiber allows to determine the wind speed with singular low power injection requirements. Moreover, this procedure makes the system immune to temperature drifts of the fiber, potentially allowing for a simple field deployment. Being a much less power-hungry scheme, this method also allows for monitoring over much longer distances, in the orders of 10s of km. We expect that this system can have application in dynamic line rating and lateral wind monitoring in railway catenary wires.

show abstract

“…A detailed description of the calibration tunnel is provided by di Mare et al (2017). Hotwire measurements were acquired within the potential core of the jet, one nozzle diameter downstream of the nozzle exit, with the flow normal to the plane of the prongs.…”

Section: Hot-wire Anemometry and Calibration Proceduresmentioning

confidence: 99%

Phase-averaged flow statistics in compressors using a rotated hot-wire technique

2017

View full text Add to dashboard Cite

produces a flow field that is inherently unsteady, threedimensional and multi-scale.It is customary to divide the unsteadiness in compressors into two categories: (1) deterministic fluctuations related to the shaft and blade frequencies and (2) broadband stochastic fluctuations related to naturally occurring turbulence. The mean square of (1) and (2) are manifest as deterministic stresses and Reynolds stresses, respectively. Furthermore, statistical moments may exhibit periodicities in both space and time. The space-time dependence of flow statistics significantly complicates the closure of the phase-averaged Navier-Stokes equations, relative to the traditional Reynolds-averaged formulation (Reynolds and Hussain 1972).The numerical prediction of compressor performance and stability rank amongst the greatest achievements of modern computational fluid dynamics (CFD) (Bradshaw 1996). Several frameworks for compressor CFD exist and include: (1) the steady-state mixing-plane method (Denton 1990; Dawes 1991; (2) the unsteady sliding-plane method (Rai 1989); and (3) the average-passage method (Adamczyk 1985). Depending on which method is adopted, the action of deterministic stresses, Reynolds stresses, or their combined effect should be modeled properly to achieve physically meaningful results. However, it is widely acknowledged that contemporary modeling practice can compromise the reliability of CFD results (Denton 2010). Ultimately, modeling uncertainties will only be reduced through improved physical understanding.To improve the understanding of momentum and energy exchange mechanisms in compressor annuli, it is imperative to acquire scale-resolved measurements in realistic, rotating, multi-bladed environments. Steady-state data are of limited value, since statistical moments of fluctuating quantities cannot be evaluated. Useful data must be highly Abstract A technique based on a rotated hot wire has been developed to characterise the unsteady, three-dimensional flow field between compressor blade rows. Data are acquired from a slanted hot wire rotated through a number of orientations at each measurement point. Phase-averaged velocity statistics are obtained by solving a set of sensor response equations using a weighted, non-linear regression algorithm. The accuracy and robustness of the method were verified a priori by conducting a series of tests using synthetic data. The method is demonstrated by acquiring a full set of phase-averaged flow statistics in the wake of a compressor stator blade row. The technique allows three components of phase-averaged velocity, six components of phase-averaged deterministic stress, and six components of phase-averaged Reynolds stress to be recovered using a single rotated hot-wire probe.

show abstract

Angular response of hot wire probes

Cited by 6 publications

References 25 publications

Experimental study of the flow field disturbance in the vicinity of single sensor hot-wire anemometer

Experimental study of the flow field disturbance in the vicinity of single sensor hot-wire anemometer

Long-range distributed optical fiber hot-wire anemometer based on chirped-pulse ΦOTDR

Phase-averaged flow statistics in compressors using a rotated hot-wire technique

Contact Info

Product

Resources

About