The measurement of dispersive waves with a real-time wave vector analyzer
Abstract
A parallel input/serial output charge coupled device (CCD) was introduced which provides a simplified real time electronics package that is capable of sampling and then delaying the signals from an array of sensors. The device was operated as an eight channel beamformer sampling at rates up to 1 MHz with time delays ranging from 1 to 800 microseconds. An accelerometer array formed a wave vector filter whose spatial properties were controlled by the selection of a master clock frequency. A real time wave vector analyzer was then created by following the output of the CCD beamformer with a set of 1/3 octave filters that allowed the wave number to be varied from 25 to 125. The dispersive nature of the wave propagation in the plate was resolved by assuming a reasonable formulation of the dispersion and then creating a simple algorithm to generate the clock frequencies appropriate to an angular display of the wave vector response. Using a line array the steerable wave vector analyzer was shown to accurately localize a vibration source for three levels of damping in the plate.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- March 1980
- Bibcode:
- 1980PhDT........64C
- Keywords:
-
- Real Time Operation;
- Turbulent Boundary Layer;
- Vector Analysis;
- Wave Propagation;
- Aluminum;
- Charge Coupled Devices;
- Spatial Distribution;
- Fluid Mechanics and Heat Transfer