f Modelling of G.I. Gun signatures

Two years ago A. Pascouet (1989) presented a new airgun called the GI gun. The main characteristic of this gun is its ability to control (i.e. damp) its own bubble oscillation. The removal of the bubble osciallion is achieved through a tuning of air injection within the bubble. In order to achieve optimal bubble suppression the amount of injected air must be of the order of two times the original amount of air used to create the primary pressure pulse (see Pascouet, 1989). It has been shown however (SSI-brochure), that even if the volume ratio between injected air and original air is reduced to 1.0 (i.e. the gun is operated in the harmonic mode), farfield signatures with a very good primary to bubble ratio can be achieved.