1

Overview of model testing facilities

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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 m Width: 10.5 m 2.8 m 10.5 m 10.5 m Depth: 5.6 m 1.0 m 10.0 m 5.6/10.0 m

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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

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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

really high speed capability – Maximum carriage speed is 10 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 • Aalto University (VTT), Finland • Aker Arctic, Finland • Memorial Univ. St. Johns, Canada • St. Petersburg, Russia • KAIST, Korea (recently established)

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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 m Width between center lines: 22.22 m Contraction area ratio: 6.25 : 1

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TEST SECTION

CONTRACTION

AIR RELEASE PIPE TO AUXILIARYPIPE SYSTEM

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CONCRETE

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NOISE INSULATION

Ø 2

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DC GEN.300HP/1000RPM

IMPELLERSYNC.MOTOR

1700HP/1000RPM RED.GEAR1000/200RPM

HATCHES

PROPELLER MOTOR300HP/3000RPM

SLIP RINGS

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Diameter of working section: 1.20 m Length 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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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 • OTRC, Texas • Lab Oceano, Brazil • CSSRC, China • Shanghai Jiao-Tong University, China • Several basins planned or under

construction in China • A new hydrodynamic test centre is

planned in Singapore

• In addition, there are many ship seakeeping basins around, such as:

– SSPA Sweden, QinetiQ (UK), DTMB (US), KRISO (Korea), …

• Seakeeping basins generally lack current capability, and has smaller water depth

Marin ocean basin: LxBxT=45x36x10.5 Pit: diam 5 m, depth 20 m Movable bottom Very 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