1

Overview of model testing facilities

Experimental Methods in Marine Hydrodynamics

2

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

3

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

4

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

11

4

10 9 8 7

136

5

3 2 1

1

5.6

10.0

28

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

12345

67

8

910

11121314

15

TANK I TANK I I I 14

5

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

6

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

7

Ice tanks

• HSVA, Hamburg• Helsinki University, VTT, Finland• Kvaerner Masa Yards, Finland• Memorial Univ. St. Johns, Canada

8

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

9

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

10

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

11

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

12

View of the test section of KTII

13

SSPA cavitation tunnel

14

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

15

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

16

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

17

Model tests in the ocean basin

18

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

19

Rotating arm basin – CSSRC, China

20

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

21

Wind tunnels• Applications:

– Testing of aerodynamic forces– Funnel smoke tests– Flow visualization– Basic flow research

• High Reynolds number can be obtained