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# Accession Number:

## AD0745295

# Title:

## SHIP (Simplified-Helmholtz-Integral Program): A Fast Computer Program for Calculating the Acoustic Radiation and Radiation Impedance for Free-Flooded-Ring and Finite-Circular-Cylinder Sources.

# Descriptive Note:

## Interim rept.,

# Corporate Author:

## NAVAL RESEARCH LAB WASHINGTON D C

# Report Date:

## 1972-06-19

# Pagination or Media Count:

##
64.0

# Abstract:

## The Naval Research Laboratory SHIP is a special-purpose acoustic radiation program designed for rapidly determining acoustic surface pressures, radiation impedances, and far-field radiation patterns for acoustic sources in the form of finite cylinders and free-flooded rings and for acoustic sources which can be approximated by such forms. The program uses a finite-element method based on a one-dimensional version of the surface Helmholtz integral equation. Axial symmetry is assumed in all cases. It is the complete use of this axial symmetry which results in the high speed of this method relative to other formulations of this problem. The basic inputs to the program are the geometry of the ring or cylinder and the normal velocity on the surface of this source. The output is a representation of the complex acoustic pressure distribution on the surface of the source, the radiation impedance, and if desired the far-field radiation pattern. The program is presently limited to a single ring or single cylinder, but it may easily be modified to handle coaxial stacks of rings and cylinders. Author

# Distribution Statement:

## APPROVED FOR PUBLIC RELEASE

#