Acoustic Radiation of Vibrating Bodies near Rigid Planes

This paper presents the boundary element method solutions of the Helmholtz integral equation for vibrating bodies near rigid planes. These solutions are performed using an in-house code generating one-half, one-quarter, and one-eighth of a free-space algorithm automatically. The code has the capability of examining near fields of acoustic sources in detail and particularly convenient for machines placed in close proximity to rigid planes. In the paper, three types of sources are handled and the acoustic effect of the presence of rigid planes is discussed. As a basic source, dilating sphere is the first source. The second one is radiating cube. The third is washing machine, as a real and common noise source disturbing the domestic comfort.The paper provides opinion about the directivity of sound pressure fields, forms their visual record in mind around vibrating bodies near reflecting surfaces; numerical vision about scattering effects of rigid walls around machinery; and also points out the possibility and feasibility of the solution of symmetric objects in half/quarter space instead of free space.