Uncertainty analysis of oscillating water column experiments under regular and random wave conditions

This paper presents a rigorous uncertainty analysis of experimental testing of an oscillating water column device. Quantifying experimental uncertainty is essential for establishing the confidence level of laboratory data and enabling a reliable transition to full-scale applications. Previous studies have focused on deterministic performance, overlooking the statistical variability inherent in random wave conditions. To address this gap, the Monte Carlo method was applied to evaluate uncertainties in oscillating water column experiments conducted under both regular and random wave conditions. A camera-based edge-detection system was employed to capture the spatio-temporal evolution of the free surface within the chamber, enabling high-accuracy assessment of pneumatic power output. The analysis examined the effects of the number of wave cycles, test duration, and random realisations on power estimation. The analysis also assessed the repeatability error in the time series for several measured and calculated quantities. Results indicate excellent repeatability, with standard deviations below 1% for all measured quantities and expanded uncertainties of approximately 1% under regular waves and 2.5% under random waves, the latter reflecting inherent variability in realistic conditions. These findings validate the robustness of the proposed measurement and analysis framework, establishing a practical methodology for quantifying uncertainty in oscillating water column experiments and improving the reliability of early-stage testing.