Static stability and ground viscous effect of a compound wing configuration with respect to reynolds number

Abstract

Static stability is a main issue of a wing-in-ground effect (WIG) craft for safe takeoff and cruise mode of flight. In this study, the effect of ground boundary layers on aerodynamic behaviour and the height static stability of a compound wing ofWIG craft were numerically studied during ground effect. First, the principal aerodynamic coefficients of numerical analysis were validated by experimental data of the compound wing. Then, these coefficients of the compound wing were obtained for fixed and moving ground conditions. Consequently, the numerical results showed that viscous ground had some effects on lift and drag coefficients and lift-to-drag ratio, whereasmoment coefficient and centre of pressure of the compound wing had small variation due to removal of ground boundary layers.The present results clarified that the ground viscous effect can be changed slightly with Reynolds number. Also, the height static stability of the compound wing will be obtained and compared with the rectangular wing one. Based on the current results, the stability of the compound wing was higher than a common rectangular wing. In addition, the height static stability of both wings was strongly affected with ground clearance. It had slight reduction then fluctuated when Reynolds number was increased.