Effects of fuselage shape on helicopter aerodynamic performance in case of intermeshing-rotor interference

Abstract

Abstract To study the influence of fuselage shape on the aerodynamic performance of a helicopter under the interference of an intermeshing-rotor, a numerical simulation method of flow field under the forward flight state of Synchropter is established based on the lattice Boltzmann method. Firstly, the Maryland helicopter was calculated to verify the scientific validity of the method. Then, the simplified S-97 fuselage was used as the object of analysis to analyze the aerodynamic data such as surface pressure, friction, and lift resistance of the fuselage with different head curvature, cross-section shapes, and transition segments under Synchropter interference with different attack angles in forward flight. The results show that increasing the radius of curvature of the nose can reduce the total drag of the fuselage; the fuselage with a circular cross-section shape has better aerodynamic characteristics of lift resistance, and the fuselage with rhombic cross-section shape has better transverse stability; the transition section with backward position, smaller upward dihedral angle, and smooth transition can avoid serious airflow separation and achieve the purpose of drag reduction.