Nonlinear Interaction of Two Noncollinear Sound Waves in a Rectangular Waveguide.
Abstract
This report examines the nonlinear interaction (in air) of two noncollinear sound waves in a rectangular waveguide. One of the waves is a low frequency, finite-amplitude wave (pump) which travels in the (0,0) mode. The other is a high frequency, small-signal wave which travels in the (1,0) mode. A formula for the modulation, and accompanying suppression, of the small-signal wave by the pump is derived. The modulation depends on the angle of intersection, theta, of the two waves because (1) only the velocity component u cos theta, of the pump convects the small-signal wave; and (2) the two waves have different group velocities (geometric dispersion). Experiments to examine both collinear and noncollinear interaction were performed in a 6.4 m long rectangular waveguide of inside cross-section 70 mm x 38 mm. Waveforms of the frequency modulated small-signal wave were recorded, the suppression of the small-signal primary was measured, and the cyclical variation (in space) of the sum and difference frequency wave amplitudes was examined. Theoretical predictions were generally confirmed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1984
- Accession Number
- ADA144440
Entities
People
- J. A. Ten Cate
Organizations
- University of Texas at Austin