Acoustic propagation in 3-D, rectangular ducts with flexible walls

摘要

In this paper some analytic expressions for acoustic propagation in 3-D ducts of rectangularrncross-section and with flexible walls are explored. Consideration is first given to thernpropagation of sound in an unlined 3-D duct formed by three rigid walls and closed by a thinrnelastic plate. An exact closed form expression for the fluid-structure coupled waves isrnpresented. The effect of incorporating internal structures, such as a porous lining, into the ductrnis also discussed. Such configurations are directly relevant to the heating, ventilation and airconditioningrn(HVAC) industry.