Uncertainty of measurements of podded propulsor performance characteristics

Abstract

One of the fundamental aspects of any physical experiment is the uncertainty or error limits of the measurement. Unfortunately, majority of published model experimental results do not come with the much needed error analysis. It is imperative that a fundamental and rigorous uncertainty assessment is carried out for all measurements, especially for measurements using a newly designed apparatus. This paper presents the uncertainty analysis methodology and results for a newly designed fully functional podded propulsor performance measurement apparatus. The measurements include propeller thrust, torque, rotation rate and advance speed as well as global forces and moments of a pod unit. The facility and measurement systems are briefly described, and detailed uncertainty assessment methodologies with examples for each measurement are provided with descriptions of bias and precision limits and total uncertainties. The generalized methodology can also be used for other relevant measurements.