Effect of Cavity on Sound Radiation from Flanged Circular Duct.

The sound radiation from a cylindrical duct having a cavity at the open end has been numerically studied. The structures of the entire sound field is numerically obtained for various depths and radii of the cavity. The governing equation for acoustic disturbance is a linearized Euler equation and is solved by a finite difference method. The present study shows that the cavity affects the sound diffraction and reflection at the open end of the duct and changes the radiated sound field. The cavity of a particular depth reduces the sound power significantly and changes the distibutions of intensity and sound pressure level at the open end of the duct.