Parametric analysis of acoustic liner in bicameral duct: An analytical perspective

Abstract

Parametric analysis of different choices of acoustic absorbent liners in a bicameral acoustic duct is presented in the current research study. Bicameral is characterized by two expansion chambers but functions as a single duct in practice, that is widely used in various engineering applications, particularly in the field of exhaust systems and to mitigate noise. The current research intends to examine the acoustic behavior in an acoustic duct when it is equipped with fibrous and perforated liners in bicameral configurations. The comparison study of rigid vertical walls of the bicameral with absorbent liner materials is addressed particularly to optimize the design of an acoustic duct to accomplish the desired acoustic performance. The current physical challenge is modeled mathematically and solved by a semi-analytical Mode-Matching (MM) approach. However, the root findings of the derived dispersion relations and recasting the system of linear algebraic equations are tackled numerically. The power fluxes, transmission-loss (TL), and absorption power ($P_{abs}$) as a function of frequency and against horizontal spacing of the chambers (L) are achieved and displayed graphically. Also, the comparison discussion is provided for both vertical rigid and vertical lining cases by assuming the various choices of fibrous absorbent liner (FAL) and perforated absorbent liner (PAL). Ahead of this, the computational validation of the analytical perspective also depends on satisfying matching continuity criteria.