Acoustics Flashcards by D J

What does SS K stand for?

Submersible ship killer - Hunter killer submarine conventionally powered

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What does SSC stand for?

Submersible ship coastal - conventionally powered

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What does SSP stand for?

Submersible ship air independent propulsion

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What does SSN stand for?

Submersible ship nuclear

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What does SSAN stand for?

Submersible ship auxiliary nuclear

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What does SSBN stand for?

Submersible ship ballistic missile nuclear

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What does SSGN stand for?

Submersible ship guided missile nuclear

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Name the advantages/ disadvantages of a nuclear submarine?

They offer advantages of range, speed, and endurance.

The disadvantage is the requirement to constantly be running the nuclear reactor causing noise

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Name advantages and disadvantages of a diesel submarine?

Diesel submarine in battery mode is quieter than a nuclear powered submarine
Limited endurance is a disadvantage and submarine has to surface for air known as snorting

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There are 7 propulsion modes, names them?

Turbo Reduction 
Turbo Electric
Diesel direct
Diesel reduction
Diesel Electric 
Battery drive
Air independent propulsion

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Name 6 components on the Turbo Reduction engine (nuclear)

Pressuriser
Reactor
Main coolant pump 
Steam generator 
Turbo generator 
Motor generator
Main turbine
Electrical propulsion motor
Main condenser
Battery
Reduction gearing

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What is the definition of sound?

Sound is defined as a periodic variation of pressure, particle displacement or particle velocity in an elastic medium

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How does temperature, depth and salinity effect AV acoustic velocity

1 degree Celsius increase in temperature increased AV by 3m/s

100 m in depth increases AV by 2M/S

1 part per thousand increase in salinity increases AV by 1.1m/s

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What does HALT stand for?

High away low towards

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Name the three layers of the ocean model?

Mixed Layer

Thermocline

Deep water

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What is the definition of ambient noise?

Ambient noise is defined as any noise within the ocean is not target related

What are the two categories of background noise?

Natural noises

Man made noise

Natural noise can be further divided as follows into four categories, what are they?

Biological
Ice
Weather
Seismic

Man made noise can be further divided as follows into what four categories?

Shipping noise
Seismic surveying
Drilling
Active transmissions (military or civilian)

What is the definition of a chokepoint name three examples?

Chokepoints are geographical features, above or below the surface of the sea, they restrict the freedom of movement of a submarine.
The English Channel
The straits of Gibraltar
Greenland-Iceland-UK Gaps

Describe the ocean bottom topography?

Continental shelf - shallows
Continental slope - abrupt drop
Continental rise - change to angle 
Ocean trench - deep area
Seamounts (jagged or flat top)
Abyssal plain - bottom of sea flat 
Mid-Atlantic ridge

What are the three main requirements of an acoustic detection system?

Good penetration (active) or sensitively (passive)
High resolution
High data rate

Name the elements of an airborne acoustic detection system?

1st Detection
Detection - amplification - demodulation

2nd Processing
Fourier Analysis

3rd Display
Display ADU - Headset audio

A low-fat gram comprises of 3 dimensions and you can process a 4th, what are they?

Time, frequency, and intensity.

Colour (bearing)

What is the definition of Doppler?

Doppler is the apparent change in frequency due to relative motion between a source and a receiver

What does DSCPA stand for?

Doppler shift closest point of approach

What are the six pieces of information that can be gained from a CPA - closest point approach

``` Speed Range Bearing Track F0 Depth ```

What is the formulae for calculating speed from CPA

Speed = 1450 x (Fmax-Fmin) divided by F0 F0 = Fmax + Fmin divided by 2

``` What do the following acronyms stand for? EFR Cyl CFR S/C CSR ERPM R:R SRPM SR BR ```

``` Engine firing rate Cylinders Cylinder firing rate Stroke cycle Cylinder shaft rate Engine RPM Reduction ratio Shaft RPM Shaft rate Blade rate ```

``` What are the main operating statics for the SSQ-53F DIFAR Size Depth & drop time Battery life Channels ```

``` Size A Depth 90ft = 40 seconds 200ft = 65 seconds 400ft = 100 seconds 1000ft = 180 seconds Battery life 0.5, 1, 2, 4, and 8 hours Channels 1-99 except 57, 58 and 93 ```

What does DIFAR stand for? And what is it’s use?

Directional frequency analysis and recording. | They are the primary passive buoy in use in the UK and their allies

The SSQ53G is similar to the SSQ53F, except for what feature?

It’s has a GPS capability

``` What are the main operating statics for the SSQ-36B Bathy Size Depth & drop time Battery life Channels ```

Size A Depth 2625ft and 5ft per second Battery life 12 minutes Channels 1-99

``` What are the main operating statics for the SSQ-62D/E DICASS Size Depth Operating life Channels ```

``` Size A Depth shallow 50ft, 150ft and 300ft Deep 90ft, 400ft and 1500ft Operating life 50 ping seconds or 60 mins Channels 1-99 except 57,58, and 93 A- 6.5khz B- 7.5khz C- 8.5khz D- 9.5khz ```

What does DICASS stand for? | And what does it do?

Directional command activated sonobuoy system | The primary active sonobuoy in use they’re able to detect and localise a Submarine

``` What are the main operating statics for the SSQ-125 MAC Size Depth Battery life Channels ```

Size A Depth 65ft, 175ft, 300ft and 500ft Battery life 8 hours or 140 ping seconds Channel 96

What does MAC stand for?

Multi static active coherent