Auto-pitch wing-in-ground effect oscillating foils for marine propulsion

An auto-pitch wing-in-ground effect oscillating foil propulsor (APWIGs) is numerically modelled by means of an unsteady Reynolds Averaged Navier-Stokes solver. Locomotion of the biplane configuration is characterized as actively heaving motion in counterphase and passively pitching motion based on hydro-elastic moment. A comprehensive computation of propulsive properties for APWIGs as a function of frequency ratio and advance coefficient is performed. A consistently high propulsive efficiency is produced by APWIGs using a frequency ratio within the range of 1.1 to 1.4. It was found that the operation of APWIGs has an independence of forward speed within current parametric space.