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DTIC ADA625680: Time-Dependent Modeling of Underwater Explosions by Convolving Similitude Source with Bandlimited Impulse from the CASS/GRAB Model

The research documented in this report was conducted to develop a time-dependent pressure computational model for an explosive source in an underwater acoustic waveguide. This objective was accomplished by convolving a time-dependent (similitude) source with the farfield impulse response from the Comprehensive Acoustic System Simulation/Gaussian Ray Acoustic Bundle (CASS/GRAB) model. The impulse response was found by performing an inverse fast Fourier transform of the frequency-dependent, bandlimited transfer function (Green s function) from CASS/GRAB. The bandlimited transfer function is determined using the CASS/GRAB amplitudes and phases over a range of frequencies. The result of this convolution is a time-dependent pressure field that satisfies the time-dependent hyperbolic wave equation with boundary conditions, which, in turn, produces a time series from the explosive source. In addition to describing the conduct of this investigation, this report presents the algorithm developed for the computational model and provides a comparison of measured and modeled data.

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