Institute for Fluid Dynamics and Ship Theory

Part I - Summary of Results

• The observed cavitation inception of the profile at Reynolds numbers 1.2·10⁶ and 1.8·10⁶ corresponded quite well with numerical (based on potential flow theory) results up to 6° angle of attack. Beyond this angle, the measured values were systematically lower due to the interference of the tunnel walls.
• A change of the cavitation nature - from bubble cavitation to sheet cavitation - at the same cavitation number was found to be due to a different absolute tunnel pressure.
• Two different sheet cavitation shedding processes were observed.
• The extent of sheet cavitation at σ = 1.8 / 1.5 / 1.0 was found to be around 0% / 20% / 40%.
• High speed video records revealed interesting details of bubble cavitation, i.e. bubble collapse, rebound and the respective effect on sheet cavitation.
• Measurements of pressure and acceleration did not reveal any correlation with the observed cavitation phenomena. No dedicated shedding frequency could be measured although local shedding of sheet cavitation was observed. The only single frequency line found was clearly identified as the tunnel impeller-blade rate.

Report Part I

Report_K_20-08 (PDF, 8.1MB)

Videos and Records of Measured Data

A data dvd with the videos and records of the measured data is freely avaible. Please send an E-mail request.