Acoustics Flashcards
What are the 7 propulsion modes?
Turbo Reduction
Turbo Electric
Diesel Direct
Diesel Reduction
Diesel Electric
Battery Drive
Air Independant Propulsion
What is the advantage of Nuclear Engine?
Range, speed and endurance
What is the disadvantage of Nuclear
Constant noise sources
Advantage of Diesel?
Very quiet on batteries
Disadvantage of Diesel
Must snort to recharge batteries
Define sound
Periodic variation of pressure, particle displacement or particle velocity in an elastic medium.
Define a choke point
Geographical feature, above or below the surface of the sea, that restricts the freedom of movement of a submarine.
Example of a choke point?
The English Channel
The Straits of Gibraltar
Greenland-Iceland-UK Gaps
What are the three main requirements of a successful underwater detection system?
Good penetration (active) or sensitivity (passive)
High resolution
High data rate
What three factors affect the speed of sound in water?
Temperature
Pressure
Salinity
Which of the three factors that affect the speed of sound has the greatest effect?
Temperature
Define the Doppler Phenomenon
Apparent change in frequency due to the relative motion between a source and receiver.
What does DIFAR stand for?
Directional Frequency Analysis & Recording
What are the selectable DIFAR Depths?
90, 200, 400, 1,000 ft
What does DICASS stand for?
Directional Command Activated Sonobuoy System
What is the DICASS operating life?
60 minutes (50 ping seconds)
What information can be gained from a CPA?
Speed Range Bearing Track F0 Depth
What does HALT stand for?
High Away, Low Towards
What are the submarine types?
SSK Submersible Ship Killer
SSC Submersible Ship Coastal
SSP Submersible Ship Air Independant Propulsion
SSN Submersible Ship Nuclear
SSAN Submersible Ship Auxillary Nuclear
SSBN Submersible Ship Ballistic Missile Nuclear
SSGN Submersible Ship Guided Missile Nuclear
What are the 2 types of seamounts that can be found in the ocean?
Pinnacles
Guyots
Define Ambient Noise
Any noise within the ocean that is not target related.
What are the two types of ambient noise?
Man-made and Natural