A Collaboration-based Approach to CFD Model Validation and Uncertainty Quantification (VUQ) Using Data from a Laminar Helium Plume

Abstract The purpose of this paper is not to present new results; rather, it is to show that the current approach to model validation is not consistent with the accepted mathematics of probability theory. Specifically, we argue that the Sandia V&V Challenge Problem is ill-posed in that the answers sought do not, mathematically, exist. We apply our arguments to show the types of mistakes present in the papers presented in the Journal of Verification, Validation and Uncertainty Quantification, Volume 1,1 along with the challenge problem. Further, we argue that, when the problem is properly posed, both the applicable methodology and the solution techniques are easily drawn from the well-developed mathematics of probability and decision theory. The unfortunate aspect of the challenge problem as currently stated is that it leads to incorrect and inappropriate mathematical approaches that should be avoided and corrected in the current literature.

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Uncertainty Quantification and Model Validation under Epistemic Uncertainty due to Sparse and Imprecise data

52nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference ◽

10.2514/6.2011-1708 ◽

2011 ◽

Author(s):

Shankar Sankararaman ◽

Sankaran Mahadevan

Keyword(s):

Uncertainty Quantification ◽

Model Validation ◽

Epistemic Uncertainty ◽

Imprecise Data

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Modal testing for model validation of structures with discrete nonlinearities

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2014.0410 ◽

2015 ◽

Vol 373 (2051) ◽

pp. 20140410 ◽

Cited By ~ 23

Author(s):

D. J. Ewins ◽

B. Weekes ◽

A. delli Carri

Keyword(s):

Model Validation ◽

Nonlinear Response ◽

Structural Integrity ◽

Linear Models ◽

Recent Literature ◽

Modal Testing ◽

Structural Dynamic ◽

Nonlinear Features ◽

Using Data ◽

Further Development

Model validation using data from modal tests is now widely practiced in many industries for advanced structural dynamic design analysis, especially where structural integrity is a primary requirement. These industries tend to demand highly efficient designs for their critical structures which, as a result, are increasingly operating in regimes where traditional linearity assumptions are no longer adequate. In particular, many modern structures are found to contain localized areas, often around joints or boundaries, where the actual mechanical behaviour is far from linear. Such structures need to have appropriate representation of these nonlinear features incorporated into the otherwise largely linear models that are used for design and operation. This paper proposes an approach to this task which is an extension of existing linear techniques, especially in the testing phase, involving only just as much nonlinear analysis as is necessary to construct a model which is good enough, or ‘valid’: i.e. capable of predicting the nonlinear response behaviour of the structure under all in-service operating and test conditions with a prescribed accuracy. A short-list of methods described in the recent literature categorized using our framework is given, which identifies those areas in which further development is most urgently required.

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