This study examines the backward bent duct buoy (BBDB) as an oscillating water column (OWC) wave energy converter

and develops a BBDB-OWC device integrated with certain foils to optimize the bottom-mounted appendages. A three-dimensional computational fluid dynamics (CFD) model is constructed in the framework of STAR-CCM+ to couple wave propagation

air chamber compression

and structural response

and focus on comprehensive analysis of the effects of foil parameters－including chord length

width

and spatial positioning－on the hydrodynamic performance of this device under regular wave conditions. The simulation results indicate the foils can alter the local flow field structure and turbulence distribution

imposing a certain influence on the vorticity field around the device. However

its contribution to the overall energy conversion efficiency is limited

with the capture width ratio varying by no more than 5%. This study demonstrates the stability of the device’s hydrodynamic performance under the effect of foils

and helps further studies on parametric design and optimization of the appendage structures for wave energy converters.