A development of longitudinal static stability analysis method of a Wing-In-Ground effect vehicle in cruise during the design process

Abstract

Traditional methods of Wing-In-Ground effect (WIG) vehicle longitudinal stability analysis in cruise are based on calculation of aerodynamic forces and moments coefficients and its derivatives. Static longitudinal stability analysis includes the determination of Irodov criteria, and functions of pitch moment coefficient versus lift force coefficient for constant angle of attack or ground clearance are considered as linear. Here the problem of development of WIG vehicle longitudinal static stability analysis method accounting the nonlinearity of pitch moment coefficient on lift force coefficient dependence for constant angle of attack is researched. WIG vehicle aerodynamic characteristics are determinate by RANS-SST numerical simulation. Results of numerical studies show that function of pitch moment coefficient versus lift force coefficient for constant angle of attack is approximated by curve of order no higher than two, and this function for constant ground clearance is linear. The relationship between static height stability, second derivative of the pitching moment coefficient with respect to lift force coefficient, and lift coefficient was derived. Reliability of analysis method is based on using of fundamental equations of WIG vehicle motion and fluid dynamics. Application of the method can simplify study of WIG vehicle stability during design process.