COMPUTER METHOD FOR CALCULATING EIGENVALUES IN ACOUSTICALLY LINED CIRCULAR DUCTS WITH UNIFORM FLOW

摘要

A direct computer method of calculating a given number of eigenvalues in acoustically lined circular ducts with uniform mean flow has been developed. The given number of different eigenvalues were obtained successfully for the wall admittances with a large absolute value, not corresponding to double eigenvalues, even if the argument is nearly equal to Arg(β_(cl)) (β_(cl): admittance for a double eigenvalue). This indicates the present method works well without restrictions on the value of wall acoustic admittance.