A Practical Method for Investigation of Aerodynamic and Longitudinal Static Stability of Wing-in-Ground Effect

Abstract

The purpose of this paper is to present a fast, economical and practical method for mathematical modeling of aerodynamic characteristics of rectangular wing-in-ground effect (WIG). Reynolds averaged Navier-Stokes (RANS) equations were converted to Bernoulli equation by reasonable assumptions. Also Helmbold's equation was developed for calculation of the slope of wing lift coefficient in ground effect by defining equivalent aspect ratio (ARe). Comparison of present work results against the experimental results has shown good agreement. Finally, according to the calculated aerodynamic coefficients, height static stability of WIG was evaluated by Irodov’s criterion in various ground clearance (h/c). A practical mathematical modeling with lower computational time and higher accuracy was presented for calculating aerodynamic characteristics of rectangular WIG. The relative error between the present work results and the experimental results was less than 8%. Also, the accuracy of the proposed method was checked by comparing with the numerical methods. The comparison showed fairly good accuracy. The evaluation of Irodov’s criterion shows that height static stability (HS) increases with reduction of the height. Aerodynamic surfaces in ground effect were used for reducing wetted surface and increasing speed in high-speed marine and novel aeronautical vehicles. The proposed method is useful for investigation of aerodynamic performance and HS of WIG vehicles and racing boats with aerodynamic surfaces in ground effect. The proposed method has reduced the computational time significantly as compared to numerical simulation that allows conceptual design of WIG craft to do with economical.

Keywords

• mathematical modeling
• aerodynamic characteristics
• static stability
• rectangular wing
• ground effect