4.2. Modeling of suction housing and acoustic analysis of inner housing
BEM was used in the acoustic analysis of the suction housing. BEM is a technique that is widely used for sound field analysis; it requires only surface integration, so it has the merit of being a numerical simulation method that is usable with a 2D element model; also, it does not require reflective conditions for the sound field. This study attempted to conduct acoustic analysis of the inner space using BEM and to identify the basic characteristics of the inner sound field based on the FRF of the inner space. For analytic modeling, only the shape of the inner space of the completed model, taken during reverse engineering, was used. In this case, the modeling information is related to boundary conditions only; that
is to say, information is available regarding the outer surface of the inner space of the housing, and not regarding its volume. The resulting model consisted of 5990 nodes and 6022 elements (Fig. 13). BEM analysis uses only boundary conditions, so the measurement
points on the internal space should be assigned. These points are called the field point. In this study’s analysis, the plane across the center of the top and bottom of the housing was selected as the field point, considering that the housing was circular.