Lift on cavitating hydrofoil

Experiment carried out at the Cavitation Laboratory at Marintek, Trondheim, Norway.

A model hydrofoil is submerged into the closed-loop cavitation tunnel, and exposed to moving water to produce cavitation. The water is moved by a ~2m diameter impeller powered by a 1.2 MW electric motor. The cavitation tunnel has a max speed of 18 m/s.

In this experiment, the water is accelerated from 0 m/s to 8 m/s. It is pumped through a flow laminator and a nozzle to produce the top speed of 8 m/s (15.6 knots).

Towards the end of the clip, tunnel pressure is reduced to 23 kPa to produce extreme cavitation. The foil is mounted with 6 degree pitch, and has a projected area of 0.1208 m^2.

The foil produced lift force of 2208 N and drag 147 N with a tunnel pressure of 83 kPa (7.8 m/s) and slight cavitation. Lift was reduced to 2182 N and drag increased to 177 N when the pressure was reduced to 23 kPa. Same fluid speed.

Category:

Science & Technology

Tags:

• Hydrodynamics
• foil
• hydrofoil
• cavitation
• kavitasjon
• marintek
• lift
• aerofoil
• pitch
• cavitating
• nozzle
• tunnel
• laboratory
• naval architecture
• marine
• engineering
• engineer
• NTH
• NTNU
• biot-savart
• vortex
• tip vortex
• winglet
• beautiful
• fully developed
• flow
• laminar flow
• boundary layer
• drag.

[hede88]

Love the experiment, well done guys..

If thats true then i would like to take that 1.2 MW electric motor and build another one using a lot less energy that you can use instead and give me some of the money you save on electricity.. I mean, seriously? It cant take 1.2 MW to drive a 2 meter impeller to give 18 m/s water flow? Or is it like instant 18m/s because then i see it needs a lot of RPM to get that flow rather quickly.. Are you sure its 1.2 Mega watt? Like a rather big windmill :S

[aenur88]

@hede88 It is actually true, it is a 1.2 MW electric motor that powers the propeller.

If you google "Marintek cavitation tunnel", you can find all the specs on SINTEF's webpages.

It takes a lot of power to move such great amounts of water. It is only in the working section that the water reaches 18 m/s, and the diameter there is "only" 1.2m. Still, that means that more than 20 m^3 is pumped every second!

[fernandes606]

very good

[hede88]

Okay, pretty cool.. I'm making a hydrofoil kitesurf board, wish icould test like that

[willibill1]

I dont grt it.

[simonfokos]

500 fotos?