Investigation of a tunable combustive sound source

The Combustive Sound Source (CSS) is a versatile underwater sound source used in underwater acoustics experiments. The source is comprised of a submersible combustion chamber which is filled with a combustive gas mixture that is ignited via spark. Upon ignition, the combustive mixture is converted into high temperature combustion byproducts which expand and ultimately collapse back to smaller volume than before ignition. Acoustic pulses are radiated by the bubble activity. The CSS can be used as a source for calibration, TL measurements, and bottom characterizations, and when deployed on the bottom can create seismic interface waves. Current environmental regulations and varying experimental needs require a tunable source that allows users to easily alter the source level, bandwidth, and signal duration. Current efforts have focused on altering the bubble growth and collapse in attempt to tune the radiated signals to meet various needs. Scale models have been constructed and tested in in-house tank experiments. Discussion will focus on the results of the study along with future plans for development and modeling.