SPEAR Model Acoustic Feasibility Tests.
Abstract
A concept for a high-power, low frequency sonar projector proposed by Hamilton Standard to the Office of Naval Research resulted in a scale model feasibility study to verify certain acoustic assumptions of the design and to evaluate various other mechanical and acoustical parameters pertinent to a full scale design. The proposed projector -- named SPEAR -- consists of two basic elements: the first is a resonant arb/piston which is used as an impedance matching device to couple the low force, high amplitude vibrations desired at the exciter to the high force, low amplitude vibrations required at the radiating face; the second basic element is the mechanical exciter which consists of banks of counter-rotating unbalanced weights supported on hydrodynamic journal bearings. The full scale projector output would be 1 megawatt of acoustic power at 400 cps with provision for both frequency modulation and amplitude control. This report describes three series of tests conducted at the USN Underwater Sound Laboratory and presents the test results along with several supporting analyses. Several models were tested. Most of these were variations of a one-fifth scale model of the proposed full scale design and utilized an electro-magnetic exciter. The test ka was approximately 2--the same as the full scale configurations. The model test program concerned itself with four areas of investigation: the acoustic impedance presented by the water to the piston face, the transmitting directivity pattern, the transmitting response or tunability, and the vibratory structural action of the device. The test results confirm that the basic assumptions of acoustic and mechanical performance made in the SPEAR design study are valid.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 30, 1962
- Accession Number
- ADA039617
Entities
People
- Lester W. Smith
Organizations
- United Technologies Corporation