Plane Waves in Air
Figure B.9 shows a 2D cross-section of a snapshot (in time)
of the sinusoidal plane wave
![$\displaystyle p(x,y,z) = p_0 + \cos(k_x x + k_y y)
$](http://www.dsprelated.com/josimages_new/pasp/img3143.png)
![$ k_x = 2\pi 5$](http://www.dsprelated.com/josimages_new/pasp/img3144.png)
![$ k_y=2\pi 5/2$](http://www.dsprelated.com/josimages_new/pasp/img3145.png)
![$ x$](http://www.dsprelated.com/josimages_new/pasp/img179.png)
![$ y$](http://www.dsprelated.com/josimages_new/pasp/img184.png)
![$ [0,1)$](http://www.dsprelated.com/josimages_new/pasp/img3146.png)
![]() |
Figure B.10 depicts a more mathematical schematic of a sinusoidal plane wave traveling toward the upper-right of the figure. The dotted lines indicate the crests (peak amplitude location) along the wave.
The direction of travel and spatial frequency are indicated by the
vector wavenumber
, as discussed in in the following section.
Next Section:
Vector Wavenumber
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Air Absorption