Main Parameters of the Sensors |
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| Parameter | R37 | R35X | |
| Components in x direction (x) | [N] | 800 | 500 |
| Components in y direction (y1, y2) | [N] | 800 | — |
| Components in z direction (z1, z2, z3) | [N] | 500 | — |
Main Parameters of the Dynamometers |
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| Parameter | J25 | H36 | R45 | |
| Propeller thrust | Tmax [N] | 3000 | 2000 | 400 |
| Propeller torque | Qmax [Nm] | 150 | 100 | 15 |
| Propeller speed | nmax [s-1] | 60 | 50 | 50 |
| Shaft angle | [°] | +15 bis -10 | ||
The SVA Potsdam operates the K15A cavitation tunnel from Kempf & Remmers. There are two measurement sections available. The length between the two vertical parts of the cavitation tunnel is 12 m, the height between the horizontal parts is 7 m. The impeller of the cavitation tunnel is powered by a 100 kW DC motor.
The cavitation tunnel has J25 and H36 dynamometers. Both dynamometers can be operated alone or together, so that tests with counter rotating and/or tandem propellers can be performed. In addition, the water- and pressure-tight R45 type inner drive dynamometer is available for special tests (i.e. overlapping propellers).
The velocity in the test section of the cavitation tunnel is determined from the pressure differential ahead of and behind the nozzle (Venturi principle). The pressure in the test section and the atmospheric pressure are also measured with pressure sensors.
For the measurement of forces on profiles, lifting surfaces, nozzles and rudders, the R37 and R35x sensors are available. By default, local speeds are measured with a laser (Powersight LDV (TSI)). For the measurement of velocity fields, a PIV measurement system from TSI can also be used.
In the small test section, cavitation tests with propellers for fast ships, special tests such as measurements on profiles and wings, speed measurement with LDV or PIV, erosion tests and calibrations of speed measurement systems are predominantly performed.
The investigation of the cavitation behaviour of propellers in the wake field of a vessel and the measurement of the propeller induced pressure fluctuations take place in the large measurement section of the cavitation tunnel. The simulation of the wake field, calculated for the full-scale Reynolds number, is made with a dummy model and additional screens [1], [2], [3], [4]. The H36 dynamometer is integrated in the dummy model. The dummy models are up to 2.60m long and geometrically similar to the ship in the stern area. Pressure sensors are arranged in the dummy model above the propeller. Standard in the SVA, the CFD calculated wake field of the full-scale model is simulated with a dummy model and additional screens.
For the investigation of the cavitation behavior of thrusters, podded drives and Voith-Schneider propellers or steering propellers, special measurement systems have been developed. The same goes for power and torque measurements on individual blades of adjustable pitch propellers at cavitation similarity.
Please read more about the various tests and test objects in the Cavitation Tunnel here.
Technical Specifications of the Test Sections |
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| Parameter | Test Section 1 | Test Section 2 |
| Measurement section length | 2600 mm | 2600 mm |
| Measurement section area | 600 mm x 600 mm | 850 mm x 850 mm |
| Contraction ratio of the nozzle | 5.96 : 1 | 2.93 : 1 |
| Maximum speed in the test section | 13 m/s | 7.5 m/s |
| Variation of the measurement section pressure | -970 mbar bis 1200 mbar | -950 mbar bis 1200 mbar |
Context Related References / Research Projects
[1] Selke, W., Heinke, H.-J.: Propelleruntersuchungen im Kavitationstunnel der Schiffbau-Versuchsanstalt Potsdam, Jahrbuch der STG, 84. Band, 1990
[2] Schmidt, D., Selke, W., Gerchev, G.: Comparative Joint Investigations in the Cavitation Tunnels of SVA and BSHC on the Prediction of Propeller-Induced Pressure Pulses, Schiffbauforschung 31 (1992) 1
[3] Heinke, H.-J.: The Influence of Test Parameters and Wake Field Simulation on the Cavitation and the Propeller Induced Pressure Fluctuations, Jahrbuch der Schiffbautechnischen Gesellschaft, 97. Band, 2003
[4] Kleinwächter, A., Hellwig-Rieck, K., Ebert, E., Kostbade, R., Heinke, H.-J., Damaschke, N. A.: PIV as a Novel Full-Scale Measurement Technique in Cavitation Research, Fourth International Symposium on Marine Propulsors, smp’15, Austin, Texas, USA, 2015