The influence of vortex core size on the helicopter blade-vortex mechanism of interaction is investigated using large eddy simulation (LES). The simulations were performed for a Reynolds number, Re = 1.3 x 106, based on the chord, c, of the airfoil (NACA0012). Computations are carried out to investigate the influence of the vortex core size on the aerodynamic coefficients and acoustic field. It was observed that the vortex core size influences the aerodynamic coefficients and aeroacoustic field. The magnitude of aerodynamic coefficients increases with the increase of vortex core size. Also the SPL values associated with BVI increase with the increase of vortex core size.