Abstract
This study examines how flume width affects the performance of a land-fixed Oscillating Water Column (OWC) wave energy converter by analysing wave interference and its link to efficiency. While wave interactions in confined flumes are known to impact device performance, the effect of the width-to-wavelength ratio (W/L) has not been fully characterised. A validated numerical model incorporating second-order Stokes waves and Shear Stress Transport (SST) k – w turbulence modelling was used to simulate flume widths ranging from 2 to 4.5 wavelengths. Reflected and scattered wave components were isolated to evaluate their influence on local wave dynamics and OWC efficiency. Results show that integer W/L ratios (e.g., W/L = n ) generate constructive interference, enhanced energy transmission, and higher OWC efficiency. Non-integer ratios (e.g., W/L = n +1/2) disrupt transverse resonance, leading to increased cancellation and reduced performance. A novel interference metric is introduced to quantify the reflected/scattered contribution and its correlation with efficiency. These findings offer guidance for OWC spacing in nearshore arrays, where aligning devices with constructive interference zones may improve overall energy capture.