Background

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Uncertainty analysis, as a branch of the wider subject of statistics, has been around for a long time. However, the benchmark book by Coleman and Steele, first published in the late 1990’s, has dramatically opened up its use in the wider engineering fields. Nevertheless, it is as yet not commonplace for engineering graduates to be exposed to the subject, in any substantial way, at degree level. This has resulted in the discipline being largely overlooked in industry. Apart from a few key specialists in the major institutions; uncertainty analysis is predominantly disregarded in the hydrodynamic testing industry. Nevertheless, in acknowledgment of growing interest, and in recognising the advantages of bringing together interested parties to form a critical mass in thinking, the 24th ITTC (2005) formed a specialist committee. After two terms the Specialist Committee on Uncertainty Analysis was absorbed (at the 26th ITTC) into the Quality Systems Group. Currently, five specialists reside in this committee, providing expertise to the other committees on uncertainty analysis.

 

Presently, the technical institutions like ours have a growing interest in measurement reliability. This relates to the use of novel, advanced measurement systems as well as to the wish to better qualify the day-to-day practice of measurements on scale models. The Hydro-Testing Forum is a platform in which a Community of Practice on Measurement Reliability would fit and in which joined-up thinking about ‘conventions’ can take place with the aforementioned ITTC- Quality Systems Group.

 

Overview of problem area

• Measurement chain

• Uncertainty analysis

• Control and reporting - ITTC convention?

 

Re. Measurement chain:

• Electronic devices: Bias, precision, error, system effects è truth?

• Calibration – zero.adjustment – dynamic measurement

• Waves – flow phenomena stochastics

• Human effects

 

Re. Uncertainty Analysis:

• Formal accuracy analysis of the measurement chain

• Analysis of systematic errors and procedural errors (human…)

 

Re. Control and reporting:

• Include accuracy standards in measurement process

• Instructions

• Awareness

• Include values in reporting of results ….. ‘future song?’

• ITTC role?

• Number of significant digits convention?

 

Note that improvements to operating procedures and reporting standards are participant’s own responsibility. The proposed CoP on Measurement Accuracy will be able to provide support and be a platform for development of guidelines, in cooperation with ITTC-QSG.