Open AccessON IMPROVEMENT OF THE IMPEDANCE EDUCATION ACCURACE BY ACCOUNT OF IMPEDANCE VARIABILITY ALONG THE ACOUSTIC LINER
Author(s) -
Vadim Palchikovskiy,
Victor Pavlogradskiy,
Aleksandr Kuznetsov,
Roman Bulbovich
Publication year - 2019
Publication title -
akustika
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.162
H-Index - 7
eISSN - 2570-8775
pISSN - 1801-9064
DOI - 10.36336/akustika20193448
Subject(s) - electrical impedance , acoustic impedance , helmholtz equation , acoustics , helmholtz free energy , mechanical impedance , physics , mathematics , mathematical analysis , mechanics , thermodynamics , quantum mechanics , boundary value problem
An impedance eduction method considering impedance variability along the acoustic liner is proposed. Impedance eduction is based on minimization of the residual functional, which is the discrepancy between the experimental and computed values of acoustic pressure at the interferometer microphones. The computed values are obtained by solving the Helmholtz equation, convected Helmholtz equation and linearized Navier-Stokes equations for a two-dimensional duct with an impedance wall and flow based on finite-element method. The cases of constant and variable impedance along the liner sample are considered. It is established that when taking into account the variable impedance, the residual functional decreases more than twofold against the case of constant impedance.