Analytical Uncertainty Analysis for Hot-Wire Measurements

Hösgen, Christian; Behre, Stephan; Hönen, H.; Jeschke, Peter

doi:10.1115/gt2016-56623

Cited by 5 publications

(4 citation statements)

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“…, for i = 1, 2, · · · , N , and V denotes the covariance matrix of parameters q. This approach was used by Bailey et al [3] to study uncertainties in zero-pressure-gradient TBL measurements using Pitot tubes, and by Hösgen et al [16] to assess uncertainties in hot-wire measurements. Linearisation can be avoided by employing sampled-based methods, in which PDFs of the QoIs are constructed by evaluation of the model response at sufficiently large numbers of realizations q (j) , randomly sampled from the joint PDF of the parameters, ρ Q (q), which is known either from a prior analysis of the measurements or by employing Bayesian techniques.…”

Section: Forward Problemmentioning

confidence: 99%

Assessment of uncertainties in hot-wire anemometry and oil-film interferometry measurements for wall-bounded turbulent flows

Rezaeiravesh

Vinuesa

Liefvendahl

et al. 2018

European Journal of Mechanics - B/Fluids

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In this study, the sources of uncertainty of hot-wire anemometry (HWA) and oil-film interferometry (OFI) measurements are assessed. Both statistical and classical methods are used for the forward and inverse problems, so that the contributions to the overall uncertainty of the measured quantities can be evaluated. The correlations between the parameters are taken into account through the Bayesian inference with error-in-variable (EiV) model. In the forward problem, very small differences were found when using Monte Carlo (MC), Polynomial Chaos Expansion (PCE) and linear perturbation methods. In flow velocity measurements with HWA, the results indicate that the estimated uncertainty is lower when the correlations among parameters are considered, than when they are not taken into account. Moreover, global sensitivity analyses with Sobol indices showed that the HWA measurements are most sensitive to the wire voltage, and in the case of OFI the most sensitive factor is the calculation of fringe velocity. The relative errors in wall-shear stress, friction velocity and viscous length are 0.44%, 0.23% and 0.22%, respectively. Note that these values are lower than the ones reported in other wall-bounded turbulence studies. Note that in most studies of wall-bounded turbulence the correlations among parameters are not considered, and the uncertainties from the various parameters are directly added when determining the overall uncertainty of the measured quantity. In the present analysis we account for these correlations, which may lead to a lower overall uncertainty estimate due to error cancellation. Furthermore, our results also indicate that the crucial aspect when obtaining accurate inner-scaled velocity measurements is the wind-tunnel flow quality, which is more critical than the accuracy in wall-shear stress measurements. 1

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Section: Forward Problemmentioning

confidence: 99%

Assessment of uncertainties in hot-wire anemometry and oil-film interferometry measurements for wall-bounded turbulent flows

Rezaeiravesh

Vinuesa

Liefvendahl

et al. 2018

European Journal of Mechanics - B/Fluids

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“…Measurement uncertainty is calculated on the basis of Hösgen's analytical approach (Hösgen et al, 2016), which uses Gauss' law of error propagation but distinguishes between systematic and random errors (Grabe, 2011). This approach considers the measuring system itself, such as resolution and noise, as well as uncertainties due to the calibration, pressure correction by the MFD approach, and probe traversing uncertainty.…”

Section: Uncertaintymentioning

confidence: 99%

“…To eliminate Table 3. Uncertainty estimation for the HWA measurements based on Hösgen et al's (2016) analytical approach with confidence interval of 95%.…”

Section: Hardwarementioning

confidence: 99%

Comparison of LDA and hot-wire measurements at moderate subsonic mach numbers

Lang

Jilke

Reymond

et al. 2023

J. Glob. Power Propuls. Soc.

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A detailed comparison of Hot-Wire-Anemometry (HWA) and Laser-Doppler-Anemometry (LDA) measurements in the wake of an airfoil is presented. An evaluation of the capabilities of both techniques in measuring three-dimensional turbulence in turbomachinery applications is made and potential application pitfalls are highlighted. It is shown that the HWA tends to underestimate the turbulence intensity due to damping effects, while the LDA tends to overestimate the turbulence intensity due to the optical setup. The wake flow of a single airfoil at inflow Mach numbers of 0.35 and 0.45 and corresponding Reynolds numbers of 480,000 and 630,000 are used as a reference case. Different HWA probe head designs and various wire diameter are considered, as well as different setups for the LDA measurement device. In a comparison of the two techniques, the turbulence intensity measured differs by up to <inline-formula><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:mn>1.3</mml:mn></mml:math></inline-formula> percentage points (pp) in the freestream region and 4.0 pp within the wake. This is primarily due to the resolution of high-frequency fluctuations. For both measuring techniques, potential sources of errors are highlighted, especially regarding the application to turbomachinery flows.

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“…The overheat temperature was set to 250 • C, the sampling rate for all measurements was 250 kHz and the measuring time was 4 s, resulting in 1,000,000 samples per measurement. Measurement uncertainty was assessed as described in [16] and is of the magnitude of ∆Tu= ±0.07 %.…”

Section: Instrumentationmentioning

confidence: 99%

Performance Analysis of a Compressor Leading Edge without Pressure Spike at High Subsonic Speed

Lang

Jeschke

Sato³

et al. 2020

JGPP

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This paper describes an experimental investigation on a state-ofthe-art compressor airfoil with three different leading edges at high subsonic flow conditions. In addition to a conventional circular and elliptical geometry which possess curvature discontinuities at the blend points, a continuous curvature leading edge is studied. The investigation considers the performance at design incidence, as well as the impact of off-design incidences. Pressure spikes near the leading edge can lead to early transition associated with higher profile losses. Goodhand and Miller [1] showed that in low subsonic conditions the avoidance of curvature discontinuities can diminish pressure spikes and therefore reduce the profile losses and enlarge the working range. In this paper, measurements are conducted to assess the potential of this concept for a high-pressure jet engine compressor airfoil operated at high subsonic conditions (M 1 = 0.7, Re d/2 = 20, 000). The results show that, at design incidence, the total pressure loss coefficient of the continuous curvature leading edge reduces by up to 15.4 % compared to the circular leading edge and by up to 3.1 % for the elliptical geometry. At off-design incidence, the reduction can be up to 40.2 % at maximum positive incidence under consideration.

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Analytical Uncertainty Analysis for Hot-Wire Measurements

Cited by 5 publications

References 0 publications

Assessment of uncertainties in hot-wire anemometry and oil-film interferometry measurements for wall-bounded turbulent flows

Assessment of uncertainties in hot-wire anemometry and oil-film interferometry measurements for wall-bounded turbulent flows

Comparison of LDA and hot-wire measurements at moderate subsonic mach numbers

Performance Analysis of a Compressor Leading Edge without Pressure Spike at High Subsonic Speed

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