ITTC 2024 Cavitation Framework • σn / σv • Tip Speed • Local Pressure Margin • Blade Loading • Erosion Exposure • Operating Envelope
Propeller Cavitation, Tip Speed, Pressure Margin & Blade Erosion Risk Tool
Screen a propeller operating point for cavitation-number margin, tip speed, immersion and observed cavitation, then use Advanced to resolve local suction-pressure margin, thrust/blade loading, operating-profile cases, hull-pressure pulses, erosion evidence and repair economics.
↑
Need much more depth? Click Advanced above.Advanced adds propeller area ratio, pitch, tip clearance, reference radius, thrust, shaft power, immersion loss, σv, |Cp|min suction-pressure margin, blade loading, pressure pulses, multiple operating points, blade condition and repair economics.Fast10 primary inputs
Core answerσn margin + tip speed + immersion
VisualOperating-point map + margin gauges
Fast Cavitation Operating-Point Screen
The inception σn and tip-speed criterion must come from maker, model-test, CFD/design or project documentation. No universal acceptance values are built in.
m.
rpm.
knots.
Used for VA = VS(1-w).
m below mean local water surface.
°C.
From project-specific model/design basis.
owner / maker / design margin.
m/s. User-entered criterion.
Propeller Geometry & Project Criteria
m.
For CPP, use effective value at the operating pitch.
m nearest hull / structure clearance.
% of propeller diameter. Project criterion only.
r/R for local pressure and velocity screen.
%.
From CFD/model/design. 0 disables pressure-margin screen.
kPa above vapour pressure after |Cp|min estimate.
m/s project criterion.
Limit for T/(0.5ρVref²AE). User-entered.
Advanced Operating Profile
Each row represents a design, ballast, heavy-weather, maneuvering or other operating point. Condition labels stay on screen only and are not transmitted through Tool Data.
| Condition | RPM | Speed kn | Wake | Thrust kN | Shaft kW | Shaft depth m | Water °C | Immersion loss m | Hours/yr | Observed cavitation |
|---|
Water, Wake & Pressure Environment
kg/m³.
kPa absolute.
Multiplier on freshwater saturation pressure.
% descriptive screening input.
kPa peak-to-peak, optional.
kPa. 0 disables this gate.
Observed Cavitation & Blade Condition
cm².
mm.
Inspection / Repair Economics
t/year.
selected currency/t.
% attributed to roughness / erosion / off-design condition.
% fuel reduction after intervention.
days.
Engineering limitation: this is a cavitation and erosion-exposure screening tool, not a propeller design approval, class calculation or substitute for cavitation-tunnel testing, CFD, wake measurement, underwater observation, maker RPM/CPP limits or vibration investigation. Local wake peaks, cavitation nuclei, dissolved gas, surface roughness, blade geometry and unsteady loading can materially change actual cavitation.