Computational fluid dynamic analysis of an unmanned amphibious aerial vehicle for drag reduction

Purpose The aim of this article is to minimize the drag of an unmanned amphibious aerial vehicle (UAAV) and enhancing the endurance. Design/methodology/approach Various surface geometrical profiles such as rectangular, semicircular groove, razor blade and V-groove riblets are incorporated into the UAAV, and computational fluid dynamic (CFD) analysis is performed for various angles of attack at diverse vehicle speed conditions to estimate the coefficient of drag considering k-e turbulence model. Comparative evaluation between riblet and blunt body shape methodology is performed. Wind tunnel experiments are conducted to validate the flow characteristics around the UAAV. Findings It is observed that V-groove riblet method produced minimal drag in comparison with other profiles. The pressure distributions around UAAV for various geometrical profiles suggested that V-groove profile has achieved minimal vortex region, flow separation and turbulent boundary layer near to the outer profile. Originality/value The CFD analysis of UAAV for various riblet configurations and validation with wind tunnel smoke test confirms that UAAV with V-groove riblet provides low drag.