Influences of the Wake Deformation and the Free-Surface on Steady Aerodynamics of Wings in the Ground Effect

Abstract

This study takes up the Wing-In-Ground effect (WIG) flying over the still water surface and addresses its steady aerodynamic properties and pressure fields focusing on the free-surface interaction effect and the influence of wake deformation. The boundary element methods both in the steady state and in the time domain are applied to two different wings in the ground effect proposing a new method which can take the viscous drag into account. The wind tunnel test and the towing test in the water are also carried out in order to validate the numerical calculations. Especially the measurements on pressure distributions over the ground are the first trial in the research field on WIG and experimental data itself is valuable. Comparisons between computed and measured results show good agreement not only on the aerodynamics but also on the pressure fields.