Movie 1:
Animation of figure 8, of the linear acoustic field within a duct opening into another duct 10 times larger, in 3D, for (a) a straight duct of aspect ratio 1/4; (b) a straight duct of aspect ratio 1/8; (c) a straight duct of aspect ratio 1/16; and (d) a duct of aspect ratio 1/16 undergoing a bend of angle 90 degrees. Each duct has a source at the inlet of frequency equal to that of the duct in question's third closed resonance (as calculated in figure 7). 8 modes were used in the inner duct, 1200 in the outer duct, and the width ratio was 1/40.

Movie 2:
Animation of figure 9, of the linear acoustic field emanating from a 1D acoustic source into a 2D duct 10 times larger. 10 modes were used in the inner calculation and 200 modes in the outer, with $\omega X_1 = 3$ for $X_1$ the inner width.

Movie 3:
Animation of figure 10, of the linear acoustic field emanating from a straight duct into a duct 10 times larger, in 2D. 10 modes were used in the inner calculation and 200 modes in the outer, with $\omega X_1 = 3$ for $X_1$ the inner width.

Movie 4:
Animation of figure 11, of the linear acoustic field emanating from a straight duct into a duct 10 times larger, in 3D. 10 modes were used in the inner calculation and 200 modes in the outer, with $\omega R_1 = 3/2$ for $R_1$ the inner radius.

Movie 5:
Animation of figure 12, of the nonlinear acoustic field within a straight duct, with a perturbation Mach number of M=0.1, opening into a duct 10 times larger (outer duct not plotted), in 2D. 10 modes were used in the inner calculation and 200 modes in the outer, with $\omega X_1 = 3$ for $X_1$ the inner radius.

Movie 6:
Animation of figure 13, of the nonlinear acoustic field emanating from a straight duct into a linear-regime duct 10 times larger, in 2D. 10 spatial modes were used in the inner calculation and 200 spatial modes in the outer, with $\omega X_1 = 3$ for $X_1$ the inner width. 7 temporal modes were used for perturbation Mach number M=0.05.

Movie 7:
Animation of figure 14, of the nonlinear acoustic field emanating from a straight duct into a linear-regime duct 10 times larger, in 3D. 10 spatial modes were used in the inner calculation and 200 spatial modes in the outer, with $\omega X_1 = 3$ for $X_1$ the inner width. 7 temporal modes were used for perturbation Mach number M=0.05.

Movie 8:
Animation of figure 15, of the linear acoustic field emanating from a curved duct into a duct 10 times larger, in 2D. 10 modes were used in the inner calculation and 200 modes in the outer, with $\omega X_1 = 3$ for $X_1$ the inner radius.

Movie 9:
Animation of figure 16, of the nonlinear acoustic field emanating from a curved duct into a linear-regime duct 10 times larger, in 2D. 10 spatial modes were used in the inner calculation and 200 spatial modes in the outer, with $\omega X_1 = 3$ for $X_1$ the inner width. 7 temporal modes were used for perturbation Mach number M=0.05.

Movie 10:
Animation of figure 17, of the linear acoustic field emanating from an exponential horn into a duct 10 times larger, in 2D (this plot shows a zoomed-in section of the outer duct, in order for the complete inner domain to be clearly visible). 40 modes were used in the inner calculation and 800 modes in the outer, with $\omega X_1 = 3$ for $X_1$ the inner radius.
