Wyniki wyszukiwania - BazTech

1

Ranges and equipment for the measurement of the ship's underwater signatures

Gloza I., Malinowski S. J., Marchalewski B.

Hydroacoustics

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2012

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Vol. 15

39-48

EN

Controlling unwanted signatures on warships is a most important effort for ship designers and naval operators. A great attempt is considerate in this field in many countries such as the USA, Germany, Sweden, Norway and in Poland as well. This paper presents ranges and techniques for the investigation of the underwater physical fields radiated by different surface ships and submarines. The Polish Naval Academy and the Naval Test and Evaluation Ranges (NTER) check and next decrease generated by the ship’s physical fields. These underwater signals can be hydroacoustic, hydrodynamic, electric, magnetic and seismic in nature. In order to have good quality measurements, there are land and sea installations, platforms on trucks, and what more a special laboratory aboard the ship. The Ranges also have a fixed and transportable multi–sensor equipment installed in a single module. This apparatus is now being used both for the measurement and for the gathering of scientific data which are next further research and analysis.

2

The old and new procedures for the investigation of underwater signatures

Gloza I., Malinowski S. J., Marchalewski B., Dobrzeniecki J.

Hydroacoustics

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2011

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Vol. 14

55-60

EN

This paper presents the results of old and new techniques for the investigations of underwater acoustic fields radiated by different objects. In the Navy Test and Evaluation Ranges (NTER), we monitor the ship radiated underwater noise, pressure and other signatures. They are of major importance to sea mines, surface ships and submarines. The NTERs contain an accurate measurement system consisting of a bottom-mounted hydrophone array, which is used for different running vessels. We also have a special laboratory ship and a transportable multisensor module, which is the most recent Polish Naval Academy product. Nowadays, the problem of protecting the civilian and military harbor facilities is becoming more and more important. There is always a threat to the ports from submarines and terrorists who dive under the water.

3

Identification of the ships underwater noise sources in the coastal region

Gloza I., Malinowski S. J.

Hydroacoustics

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2002

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Vol. 5

9--16

EN

The results of the investigations of underwater noise radiated by ships at the background of the ambient sea noise in the coastal region are presented. Sounds in shallow water are inherently modified by the local environment. Based on the results of the measurements of both the ambient noise and the noise radiated by ships the investigations of the influence of the ship's motion on the ambient sea noise were carried out. What more the noise field at the sea in the coastal region is notably influenced with the technical noise, especially connected with the human's activity.

4

Underwater noise radiated by ships, their propulsion and auxiliary machinery, and propellers

Malinowski S. J., Gloza I., Domagalski J.

Hydroacoustics

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2001

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Vol. 4

165--168

EN

These underwater radiated noise and vibration measurements were conducted on a full-scale ship in August 2000. During the trails it was found that several spike noises are dominant. To find the location of high vibration level places and its frequencies, and the machines, which generated high level point noise components, 4 accelerometers were fixed in the engine and auxiliary rooms .We were using this system to find the relationship between certain manoeuvres and the vibration level caused by them. Propellers and engines are usually the major sources of noise in ships but gearboxes can also be significant contributors. The way of mounting of the machines and the resulting vibration of the hull are determining issues in the radiation of underwater noise. Naval Test and Evaluation Acoustic Ranges contain an accurate radiated noise measurement system consisting of a bottom-mounted hydrophone array for sailing condition and a stationary range. The sophisticated digital narrow-band instruments and analogue recorders were used by us.

5

The character of underwater noise radiated by small vessels

Malinowski S. J., Gloza I., Domagalski J.

Hydroacoustics

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2001

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Vol. 4

161--164

EN

This paper presents an overview of our initiatives for underwater noise measurements and their acoustic characteristics, which years ago have been applied. Different kinds of surface ships and more importantly submarines radiate high levels of underwater noise which can be detected and tracked by passive sonars. Hostile navies use these signatures for detection and classification of targets. In many cases, not only a vessel as a specific class of warship, but also even the individual ship within a concrete class can be positively identified. The method of narrow-band filtration of the spectrum' s discrete lines at frequencies up to several H: is the basic standard of passive systems for long-distance detection. To find the source of noise, the level of vibration was also measured by accelerometers. Ship' s very own distinctive acoustic signature radiated at discrete frequencies, excited by the machinery, is easily detected and must be decreased as much as possible. Coherence between underwater sound pressure from a moving vessel and vibration during the same run was made.

6

Pomiar dźwięków foki szarej

Malinowski S. J., Gloza I., Domagalski J.

Hydroacoustics

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2000

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Vol. 3

177--182

EN

Animals produce a wide range of sounds that can travel at great distances underwater. During the presentation you will listen to the real hydrophone recordings which were made here in Hel. The paper & recordings present the results of sound imitated by grey seals. Signature sounds differ between the individuals. Seals have a well-developed sense of hearing, especially in the water. In the air, their hearing ability is greatly reduced. They have large eyes and their underwater vision is better than a human 's, but even blind mammals are healthy, because the most important sense in the water is hearing, Researchers know that seals have an acute sense of smell on land. This sense is important for mothers identifying their pups. The results of the measurements show that the sound intensity method is worth using, especially in pools , shallow water, and to identify and find the direction of a sound source.