Superposition of plane waves in same direction

This animation shows the superposition of two plane waves traveling the same direction. The two component waves have a 90 degree phase difference. The resulting superposition is a simple traveling wave in the same direction with the same frequency and wavelength but with a unique amplitude and phase.

The left side of the figure shows a representation of the molecular distribution. The darker areas represent areas where the density is greater indicating a compression. Midway between the compressions are regions of lower density indicating rarefactions.

The right side of the figure shows a plot of the resulting acoustic pressure or acoustic velocity profile.

These animations were generated using MATLAB and saved as AVI files. The AVI files were converted to animated GIF files using the Ulead Gif Animator software.