The ground viscous effect is an objective that could be an essential parameter for the conceptual design of wingin-
ground effect (WIG) crafts. This study numerically investigates the effect of ground boundary layers on the
aerodynamics of a compound wing of a WIG craft. Computational simulations were conducted to evaluate
various design parameters such as middle span size, anhedral angle and taper ratio. The flow structure in the
physical domain around the wing surface was demonstrated with a realizable k-? turbulent model. The numerical
results of the compound wing for a fixed ground boundary condition were then further validated using experimental
data from the wind tunnel. The principal aerodynamic coefficients of compound wings were achieved
for both fixed and moving ground conditions. The numerical simulations demonstrated that the ground viscous
effect of fixed ground has some effects on lift and drag coefficients and lift-to-drag ratio, including a reduction in
the lift coefficient and an increase in the drag coefficient compared with the moving ground. However, the
design parameters had a different impact on the ground viscous effect. Nevertheless, the results are predicted to
be able to provide a more fine-grained understanding on the ground viscous effect on WIG craft.