Investigation into Ground Effect for an Underwater Biologically Inspired Flapping Foil.

摘要

The topic was whether there is a lift and thrust benefit to flapping an underwater, biologically inspired three dimensional foil near the solid bottom surface (so that it was in ground effect). Data proved in all sixteen experimental cases for varying Strouhal number and maximum angle of attack that the mean lift coefficient near the bottom was larger than that in the freestream. Only under certain kinematic conditions was the mean thrust coefficient larger near the bottom than that in the freestream. The largest useful change in maximum instantaneous lift force was 14%. Benefit was larger than 1 deg pitch bias difference at a zero mean lift coefficient. Largest change in mean thrust coefficient was 8%.