overview of model testing facilities
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Overview of model testing facilities
Experimental Methods in Marine Hydrodynamics
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Types of facilities• Towing tanks
– Conventional – High-speed– Shallow water tanks– Ice tanks– Depressurised towing tanks, to test with cavitation
• Cavitation tunnels– With or without free water surface– With or without possibility to test an entire ship model
• Ocean Basins– Modelling of waves, wind and current– Variable water depth?
• Rotating arm basins• Wind tunnels
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Towing tanks - Applications
• Resistance and propulsion tests of ship models• Open water testing of propellers and propulsion systems• Seakeeping tests in head and following seas• Maneuvering tests
– Planar motion mechanism (PMM)– Small zig-zag tests
• Seakeeping and towing operations of offshore structures• Testing of various types of structures
– Towed arrays– Deflectors for seismic surveys– Torpedoes– Hydrofoil systems
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Towing tanks at Marine Technology Centre
* Tank I and III can be used simultaneously and also as one long tank (Tank I +III) by removing the gate (12) and wave absorber (15).
Tank I Tank II Tank III Tank I +III*Length: 175.0 m 25.0 m 85.0 m 260.0 mWidth: 10.5 m 2.8 m 10.5 m 10.5 mDepth: 5.6 m 1.0 m 10.0 m 5.6/10.0 m
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10 9 8 7
136
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3 2 1
1
5.6
10.0
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39 85260
13.5
10.5
Model storeDrawing officeReceptionTank IIShip model manufacturing shopTrimming tankNC milling machine for model productionInstrumentation workshop
Carpenter workshopPropeller model manufacturing shopCavitation laboratoryDock gateWave absorber, Tank I + IIIWavemaker, Tank III and Tank I+IIIWave absorber, Tank III
12 15
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11121314
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TANK I TANK I I I 14
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High-speed tanks
• Carriage speeds up to 25.7 m/s• Usually smaller cross-sections than
conventional tanks• Testing of:
– Performance of high-speed vessels– Torpedoes (often in full scale)– Foil systems
• The Marine Technology Centre lacks real high speed capability
– Maximum carriage speed is 8.5 m/s
DTMB high speed carriage:- L/B/T=514/6.4/4.9 m- Max speed: 25.7 m/s
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Shallow water tanks• To test ship performance in shallow water
– Resistance– Propulsion– Maneuvering (PMM)– Seakeeping
• Mainly used for testing crafts for inland waterways • Adjustable water depth (by draining water)• Facilities:
– Duisburg, Germany– Marin, NL– … many more
• At the Marine Technology Centre we can use the ocean basin with adjustable bottom
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Ice tanks
• HSVA, Hamburg• Helsinki University, VTT, Finland• Kvaerner Masa Yards, Finland• Memorial Univ. St. Johns, Canada
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HSVA Large Ice Tank
Large Ice Model Basin Length 78 m Breadth 10 m Depth 2.5 m Ice Freezing Rate 2 mm/hour Towing Carriage Speed Range 1 mm/s ..3 m/s Towing Capacity 5 tons
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Depressurised towing tank• CSSRC, China• Marin, Netherlands:
– Dimensions: 240 x 18 x 8 m– Carriage speed: up to 8 m/s– Models: 2 – 12 m in length, Max prop. Diam. 0.4 m.– Test to be performed
• Cavitation observation and inception• Pressure fluctuation measurements• Radiated noise measurements
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Cavitation tunnels
• Pressure can be reduced to obtain cavitation• Model is stationary – water is circulating• Types of tests
– Propeller cavitation– Pressure fluctuation on hull from propeller cavitaiton– Measurement of noise from cavitating propeller– Performance of hydrofoils– Performance tidal energy devices
• Options– Free water surface
• Testing of waterjets, ventilation effects– Testing of entire ship model
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The large cavitation tunnel at the Marine Technology Centre
Height between center lines: 10.00 mWidth between center lines: 22.22 mContraction area ratio: 6.25 : 1
2082
30008000
25123
7O CONE
TEST SECTION
CONTRACTION
AIR RELEASE PIPE TO AUXILIARYPIPE SYSTEM
FIXED POINT
Ø 3000
TO AUXILIARYPIPE SYSTEM
CONCRETE
Ø 3
000
8O CONE
Ø 2
204
CO
NTR
OLL
ABL
EPI
TCH
IMP
ELLE
R
1000
0
1300
0
NOISE INSULATION
Ø 2
400
Ø 2100
17100
DC GEN.300HP/1000RPM
IMPELLERSYNC.MOTOR
1700HP/1000RPM RED.GEAR1000/200RPM
HATCHES
PROPELLER MOTOR300HP/3000RPM
SLIP RINGS
AIR RELEASE
2 STEEL SUPPORT BEAMS
1500
Ø 3
000
DIA. 1200
HATCHES
Diameter of working section: 1.20 mLength of working section: 2.08 m
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View of the test section of KTII
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SSPA cavitation tunnel
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HYCAT - HSVA• Types of tests:
– wake distribution measurements– cavitation inception tests, cavitation
tests – pressure fluctuation measurements– thrust-, torque measurements– noise measurements of cavitating and
non-cavitating propellers– noise source detection– measurement of rudder forces– flow visualization studies– influence of appendages on wake,
cavitation and propulsion– influence of gas content of the water on
cavitation, noise and pressure fluctuations
– detection of cavitation erosion
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Ocean basins
• Possibility to simulate complete ocean environment– Waves from different directions– Short-crested waves– Current– Wind
• Beam almost same as length– Can test ships at various headings towards the waves
• Typical tests:– Testing of fixed and moored offshore structures– Testing of marine operations– Ship seakeeping tests– Ship maneuvering tests
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TOW
ING
TA
NK
OCEAN BASIN
50 mMulti-flapwave maker
80 m
Cross-section of Ocean Basin
Double-flapwave maker
Multi-flapwave maker Double-flap
wave maker
Ocean basin at Marine Technology Centre
Length: 80 m - Width: 50 m - Depth: 0-10 m
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Model tests in the ocean basin
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Other ocean basins
• Marin• Memorial University, St. Johns• QinetiQ, UK• OTRC, Texas• DTMB• KRISO, Korea• CSSRC, China• SSPA, Sweden
Marin ocean basin:LxBxT=45x36x10.5Pit: diam 5 m, depth 20 mMovable bottomVery good current capability
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Rotating arm basin – CSSRC, China
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Rotating arm basins• Captive model ship maneuvering tests• Testing of torpedoes and submarines• Often capable of very high speed testing• Locations:
– CSSRC, China– DTMB, USA– QinetiQ, UK
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Wind tunnels• Applications:
– Testing of aerodynamic forces– Funnel smoke tests– Flow visualization– Basic flow research
• High Reynolds number can be obtained