| 摘要 |
The novel method substantially reduces the pressure pulse, generated by a first radial motion of a body of water, by changing the radial motion into axial motion. The change from radial motion into axial motion is produced by generating a second radial motion of opposite phase within the body of water. The method can be used to substantially reduce the pressure pulse, generated by the implosion of a body of water, by generating an explosion in the body of water. It can also substantially reduce the pressure pulse generated by an explosion within a body of water, by generating an implosion of the body of water. The method can further be used to generate within a body of water an impulsive acoustic signal by sequentially generating within the body of water a first explosion and a second explosion. The apparatus comprises a signal chamber which contains a first charge of gas. A normally-closed valve maintains the signal chamber closed and has a discharge port into the water. A second chamber contains a second charge of compressed gas. A second fast-acting valve normally maintains the second chamber closed and has an outlet into the water. A controller explosively opens the first valve so as to generate an impulsive acoustic signal and a first bubble. The controller subsequently opens the second valve to thereby release the second charge from the second chamber into the water, while the first bubble is near is maximum volume.
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