| Acoustic liners remain the standard method for reducing environmental noise emanating from aircraft engine nacelles. To aid in liner testing and development, facilities capable of accurately educing the acoustic impedance in the presence of mean flow analogous to an aircraft engine are required. A facility was built to facilitate novel design approaches and studies into fundamental acoustic liner flow physics.;This thesis details the design, testing, and implementation of the Grazing Flow Impedance Duct (GFID) as an experimental test bench capable of educing the impedance of an acoustic liner. Each component of the facility is discussed detailing the specific features applicable toward the facility as a grazing flow acoustic test bench. Characterization of both the underlying fluid dynamics and acoustics are tested to determine the abilities and inherent limitations associated with the facility. Comparisons are made to similar facilities. Finally, an acoustic liner provided by NASA is tested under grazing flow conditions and the impedance educed by applying the single mode method with favorable results. The thesis ends with an exploratory investigation of the drag impact of an acoustic liner through three indirect velocity profile methods. |
