Describing the Uncertainties in Experimental Results
01 Jan 1988-Experimental Thermal and Fluid Science (EXPERIMENTAL THERMAL AND FLUID SCIENCE)-Vol. 1, Iss: 1, pp 3-17
TL;DR: The material presented in this paper covers the method of describing the uncertainties in an engineering experiment and the necessary background material, as well as a technique for numerically executing uncertainty analyses when computerized data interpretation is involved.
About: This article is published in Experimental Thermal and Fluid Science.The article was published on 1988-01-01. It has received 6868 citations till now. The article focuses on the topics: Uncertainty analysis & Sensitivity analysis.
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22 Nov 2010TL;DR: A comprehensive and systematic development of the basic concepts, principles, and procedures for verification and validation of models and simulations that are described by partial differential and integral equations and the simulations that result from their numerical solution.
Abstract: Advances in scientific computing have made modelling and simulation an important part of the decision-making process in engineering, science, and public policy. This book provides a comprehensive and systematic development of the basic concepts, principles, and procedures for verification and validation of models and simulations. The emphasis is placed on models that are described by partial differential and integral equations and the simulations that result from their numerical solution. The methods described can be applied to a wide range of technical fields, from the physical sciences, engineering and technology and industry, through to environmental regulations and safety, product and plant safety, financial investing, and governmental regulations. This book will be genuinely welcomed by researchers, practitioners, and decision makers in a broad range of fields, who seek to improve the credibility and reliability of simulation results. It will also be appropriate either for university courses or for independent study.
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TL;DR: In this article, the authors used a low-speed, high-Reynolds-number facility and a high-resolution laser-Doppler anemometer to measure Reynolds stresses for a flat-plate turbulent boundary layer from Reθ = 1430 to 31 000.
Abstract: Despite extensive study, there remain significant questions about the Reynolds-number scaling of the zero-pressure-gradient flat-plate turbulent boundary layer. While the mean flow is generally accepted to follow the law of the wall, there is little consensus about the scaling of the Reynolds normal stresses, except that there are Reynolds-number effects even very close to the wall. Using a low-speed, high-Reynolds-number facility and a high-resolution laser-Doppler anemometer, we have measured Reynolds stresses for a flat-plate turbulent boundary layer from Reθ = 1430 to 31 000. Profiles of u′2, v′2, and u′v′ show reasonably good collapse with Reynolds number: u′2 in a new scaling, and v′2 and u′v′ in classic inner scaling. The log law provides a reasonably accurate universal profile for the mean velocity in the inner region.
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Cites methods from "Describing the Uncertainties in Exp..."
...This can be calculated with a perturbation analysis (Moffat 1988),...
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...This can be calculated with a perturbation analysis (Moffat 1988), which estimates the uncertainty in δ for the Reθ = 31 000 case to be ±3%, and for the lower-Reynolds-number cases, ±1%....
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TL;DR: In this article, an experimental study of heat transfer and flow regimes during condensation of refrigerants in horizontal tubes was conducted, where measurements were made in smooth, round tubes with diameters ranging from 3.14 mm to 7.04 mm.
Abstract: An experimental study of heat transfer and flow regimes during condensation of refrigerants in horizontal tubes was conducted. Measurements were made in smooth, round tubes with diameters ranging from 3.14 mm to 7.04 mm. The refrigerants tested were R-12, R-22, R-134a, and near-azeotropic blends of R-32/R-125 in 50 percent/50 percent and 60 percent/40 percent compositions. The study focused primarily on measurement and prediction of condensing heat transfer coefficients and the relationship between heat transfer coefficients and two-phase flow regimes. Flow regimes were observed visually at the inlet and outlet of the test condenser as the heat transfer data were collected. Stratified, wavy, wavy annular, annular, annular mist, and slug flows were observed. True mist flow without a stable wall film was not observed during condensation tests. The experimental results were compared with existing flow regime maps and some corrections are suggested. The heat transfer behavior was controlled by the prevailing flow regime. For the purpose of analyzing condensing heat transfer behavior, the various flow regimes were divided into two broad categories of gravity-dominated and shear-dominated flows. In the gravity dominated flow regime, the dominant heat transfer mode was laminar film condensation in the top of the tube. This regime was characterized by heat transfer coefficients that depended on the wall-to-refrigerant temperature difference but were nearly independent of mass flux. In the shear-dominated flow regime, forced-convective condensation was the dominant heat transfer mechanism. This regime was characterized by heat transfer coefficients that were independent of temperature difference but very dependent on mass flux and quality. Heat transfer correlations that were developed for each of these flow regimes successfully predicted data from the present study and from several other sources.
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TL;DR: In this article, a small circular channel (d = 2.46) and a small rectangular channel with Refrigerant 12.5 was used to study the effects of channel geometry and fluid properties on heat transfer.
545 citations
References
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Journal Article•
7,568 citations
"Describing the Uncertainties in Exp..." refers background or methods in this paper
...A rational way to use the framework of statistical inference to estimate the uncertainty in these single-sample experiments was described by Kline and McClintock [1] and still forms the basis for this branch of the an....
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..." Kline and McClintock [1] attribute this definition to Airy [2], and it still seems an appropriate and valuable concept....
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...This issue was taken up by Kline and McClintock [1], who showed that the uncertainty in a computed result could be estimated with good accuracy using a root-sum square combination of the effects of each of the individual inputs and that the RSS operation preserved the odds....
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TL;DR: The concepts presented here were developed in connection with heat transfer and fluid mechanics research experiments of moderately large size and which may frequently require three experiments to be conducted.
Abstract: Uncertainty Analysis is the prediction of the uncertainty interval which should be associated with an experimental result, based on observations of the scatter in the raw data used in calculating the result. In this paper, the process is discussed as it applies to single-sample experiments of the sort frequently conducted in research and development work. Single-sample uncertainty analysis has been in the engineering literature since Kline and McClintock's paper in 1953 [1] and has been widely, if sparsely, practiced since then. A few texts and references on engineering experimentation present the basic equations and discuss its importance in planning and evaluating experiments (see Schenck, for example [2]). Uncertainty analysis is frequently linked to the statistical treatment of the data, as in Holman [3], where it may be lost in the fog for many student engineers. More frequently, only the statistical aspects of data interpretation are taught, and uncertainty analysis is ignored. For whatever reasons, uncertainty analysis is not used as much as it should be in the planning, development, interpretation, and reporting of scientific experiments in heat transfer and fluid mechanics. There is a growing awareness of this deficiency among standards groups and funding agencies, and a growing determination to insist on a thorough description of experimental uncertainty in all technical work. Both the International Standards Organization [4] and the American Society of Mechanical Engineers [5] are developing standards for the description of uncertainties in fluid-flow measurements. The U. S. Air Force [6] and JANNAF [7] each have handbooks describing the appropriate procedures for their classes of problems. The International Committee on Weights and Measures (CIPM) is currently evaluating this issue [8]. The prior references, with the exception of Schenck and, to a lesser extent, Holman, treat uncertainty analysis mainly as a process for describing the uncertainty in an experiment, and end their discussion once that evaluation has been made. The present paper has a somewhat different goal: to show how uncertainty analysis can be used as an active tool in developing a good experiment, as well as reporting it. The concepts presented here were developed in connection with heat transfer and fluid mechanics research experiments of moderately large size (i.e., larger than a breadbox and smaller than a barn) and which may frequently require three
846 citations
804 citations
"Describing the Uncertainties in Exp..." refers methods in this paper
...This direct computer-executed uncertainty analysis can be accomplished by sequentially perturbing the inputs according to the following procedure [4]:...
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...Single-sample uncertainty analysis has been described in the engineering literature by the works of Kline and McClintock [ 1] and Moffat [3, 4]....
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604 citations
01 Feb 1973
TL;DR: In this paper, a standard uncertainty methodology for estimating the errors associated with gas turbine performance data has been proposed, which is based on two components of measurement error: the fixed bias and the random precision.
Abstract: : The lack of a standard method for estimating the errors associated with gas turbine performance data has made it impossible to compare measurement systems between facilities, and there has been confusion over the interpretation of error analysis. Therefore, a standard uncertainty methodology is proposed in this Handbook. The mathematical uncertainty model presented is based on two components of measurement error: the fixed (bias) error and the random (precision) error. The result of applying the model is an estimate of the error in the measured performance parameter. The uncertainty estimate is the interval about the measurement which is expected to encompass the true value. The propagation of error from basic measurements through calculated performance parameters is presented. Traceability of measurement back to the National Bureau of Standards and associated error sources is reviewed.
125 citations
"Describing the Uncertainties in Exp..." refers background or methods in this paper
...This document is a direct outgrowth of the early work of Abernethy and Thompson [5] and clearly reflects this view in its statement of purpose:...
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...The techniques of multiple-sample analysis are described by Abernethy and Thompson [5] and summarized by Abernethy et al [6] and by ANSI/ASME PTC 19....
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