Evaluation of Measurement Uncertainties for Pneumatic Multi-Hole Probes Using a Monte Carlo Method

Author(s):  
Magnus Hölle ◽  
Christian Bartsch ◽  
Peter Jeschke

The subject of this paper is a statistical method for the accurate evaluation of the uncertainties for pneumatic multi-hole probe measurements. The method can be applied to different types of evaluation algorithms and is suitable for steady flowfield measurements in compressible flows. The evaluation of uncertainties is performed by a Monte Carlo method (MCM), which is based on the statistical law of large numbers. Each input quantity, including calibration and measurement quantities, is randomly varied on the basis of its corresponding probability density function (PDF) and propagated through the deterministic parameter evaluation algorithm. Other than linear Taylor series based uncertainty evaluation methods, MCM features several advantages. On the one hand, MCM does not suffer from lower-order expansion errors and can therefore reproduce nonlinearity effects. On the other hand, different types of PDFs can be assumed for the input quantities and the corresponding coverage intervals can be calculated for any coverage probability. To demonstrate the uncertainty evaluation, a calibration and subsequent measurements in the wake of an airfoil with a 5-hole probe are performed. MCM is applied to different parameter evaluation algorithms. It is found that the MCM approach presented cannot be applied to polynomial curve fits, if the differences between the calibration data and the polynomial curve fits are of the same order of magnitude compared to the calibration uncertainty. Since this method has not yet been used for the evaluation of measurement uncertainties for pneumatic multi-hole probes, the aim of the paper is to present a highly accurate and easy-to-implement uncertainty evaluation method.

Author(s):  
Magnus Hölle ◽  
Christian Bartsch ◽  
Peter Jeschke

The subject of this paper is a statistical method for the evaluation of the uncertainties for pneumatic multihole probe measurements. The method can be applied to different types of evaluation algorithms and is suitable for steady flow-field measurements in compressible flows. The evaluation of uncertainties is performed by a Monte Carlo method (MCM). Each calibration and measurement input quantity are randomly varied on the basis of its corresponding probability density function (PDF) and propagated through the deterministic parameter evaluation algorithm. Other than linear Taylor series based uncertainty evaluation methods, the MCM features several advantages: it does not suffer from lower-order expansion errors and can therefore reproduce nonlinearity effects. Furthermore, different types of PDFs can be assumed for the input quantities, and the corresponding coverage intervals can be calculated for any coverage probability. To demonstrate the uncertainty evaluation, a calibration and subsequent measurements in the wake of an airfoil with a five-hole probe are performed. The MCM is applied to different parameter evaluation algorithms. It is found that the MCM cannot be applied to polynomial curve fits, if the differences between the calibration data and the polynomial curve fits are of the same order of magnitude compared to the calibration uncertainty. Since this method has not yet been used for the evaluation of measurement uncertainties for pneumatic multihole probes, the aim of this paper is to present a highly accurate and easy-to-implement uncertainty evaluation method.


Metrologia ◽  
2007 ◽  
Vol 44 (5) ◽  
pp. 319-326 ◽  
Author(s):  
T J Esward ◽  
A de Ginestous ◽  
P M Harris ◽  
I D Hill ◽  
S G R Salim ◽  
...  

2017 ◽  
Vol 13 ◽  
pp. 585-592 ◽  
Author(s):  
S. Aguado ◽  
P. Pérez ◽  
J.A. Albajez ◽  
J. Velázquez ◽  
J. Santolaria

2015 ◽  
Vol 15 (2) ◽  
pp. 72-76 ◽  
Author(s):  
S. Iakovidis ◽  
C. Apostolidis ◽  
T. Samaras

Abstract The objective of the present work is the application of the Monte Carlo method (GUMS1) for evaluating uncertainty in electromagnetic field measurements and the comparison of the results with the ones obtained using the 'standard' method (GUM). In particular, the two methods are applied in order to evaluate the field measurement uncertainty using a frequency selective radiation meter and the Total Exposure Quotient (TEQ) uncertainty. Comparative results are presented in order to highlight cases where GUMS1 results deviate significantly from the ones obtained using GUM, such as the presence of a non-linear mathematical model connecting the inputs with the output quantity (case of the TEQ model) or the presence of a dominant nonnormal distribution of an input quantity (case of U-shaped mismatch uncertainty). The deviation of the results obtained from the two methods can even lead to different decisions regarding the conformance with the exposure reference levels.


2010 ◽  
Vol 2010.16 (0) ◽  
pp. 447-448
Author(s):  
Shinichi Naito ◽  
Zenichi Miyagi ◽  
Youichi Bitou ◽  
Kensei Ehara

2013 ◽  
Vol 684 ◽  
pp. 429-433 ◽  
Author(s):  
Hong Li Li ◽  
Xiao Huai Chen ◽  
Hong Tao Wang

There is presented a complete uncertainty evaluation process of end distance measurement by CMM. To begin with, the major sources of uncertainty, which would influence measurement result, are found out after analyzing, then, the general mathematic model of end distance measurement is established. Furthermore, Monte Carlo method (MCM) is used, and the uncertainty of the measured quantity is obtained. The complete results are given out, so the value of CMM is enhanced. Moreover, seen from the evaluation example, the results of uncertainty evaluation obtained from MCM method and from GUM method are compared, the comparison result indicates that the mathematic model is feasible, and using MCM method to evaluate uncertainty is easy and efficient, having practical value.


MAPAN ◽  
2019 ◽  
Vol 34 (3) ◽  
pp. 295-298
Author(s):  
P. Rachakonda ◽  
V. Ramnath ◽  
V. S. Pandey

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4472 ◽  
Author(s):  
Mingotti ◽  
Peretto ◽  
Tinarelli ◽  
Ghaderi

The paper addresses the evaluation of the uncertainty sources of a test bed system for calibrating voltage transformers vs. temperature. In particular, the Monte Carlo method has been applied in order to evaluate the effects of the uncertainty sources in two different conditions: by using the nominal accuracy specifications of the elements which compose the setup, or by exploiting the results of their metrological characterization. In addition, the influence of random effects on the system accuracy has been quantified and evaluated. From the results, it emerges that the choice of the uncertainty evaluation method affects the overall study. As a matter of fact, the use of a metrological characterization or of accuracy specifications provided by the manufacturers provides respectively an accuracy of 0.1 and 0.5 for the overall measurement setup.


Sign in / Sign up

Export Citation Format

Share Document