gamma 1.4 Ratio of specific heats M -0.5 Mean flow Mach number m 10 Circumferential mode number omega 16 Angular frequency f omega/(2*pi) Frequency rho0 1 Reference density C0 1 Reference mean speed of sound A 0.01 Acoustic source strength Z 2-i Duct wall impedance b 0.01 Impedance onset rate zi 1.86393 Axial coordinate, inlet plane zt 2.86393 Axial coordinate, terminal plane