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Large vessels sometimes use electrical propulsion motors, the electrical power being provided by a diesel generator. Noise and vibration of electric motors include, besides mechanical and aerodynamic sources, an electromagnetic source due to electromagnetic forces which is responsible for the "whining noise" of the motor.
Electronic noise control: Electronics, sensors, and computers are also employed to cancel noise by using phase cancellation which matches the sound amplitude with a wave of the opposite polarity. This method employs the use of an active sound generating device, such as a loudspeaker to counteract ambient noise in an area.
The DUBV 43C towed array sonar of La Motte-Picquet.. A towed array sonar is a system of hydrophones towed behind a submarine or a surface ship on a cable. [1] Trailing the hydrophones behind the vessel, on a cable that can be kilometers long, keeps the array's sensors away from the ship's own noise sources, greatly improving its signal-to-noise ratio, and hence the effectiveness of detecting ...
The Masker portion of the system is designed to silence a vessel's engine noise from detection by threat vessels and to reduce self-noise to increase the vessel's own sonar efficiency. The Masker portion typically consists of two bands fitted to the outside of the hull adjacent the vessel's engine rooms, compressed air is then forced into the ...
A direct field is generated by audio drivers arranged to encircle the test article. Two different control schemes can be used to perform a direct field test. One method, known as single-input-single-output or SISO, uses a single drive signal to all acoustic drivers with multiple control microphones averaged to produce the control measurement.
Active vibration control; Anvis Group; Ayodele Awojobi; B. Balancing of rotating masses; ... Noise and vibration on maritime vessels; Noise, vibration, and harshness;
The responses are a function of the environment and the vessel characteristics. Seakeeping performance criteria : the established limits for the ship's responses. These are based on the ship motions and the accelerations experienced, and include comfort criteria such as noise, vibration and sea sickness , performance based values such as ...
The commissioned officers had comparatively roomy accommodation in the wardroom aft, although it suffered from being situated above the propeller shafts and therefore subject to noise and vibration. The wardroom also contained the ship's safe, a dining table and seating, a wine and spirit locker, a small coal stove and a tiny footbath.