I don't claim to be an expert on the subject, and it has been a while since I was involved in managing any tank testing programs, but I did spend...
Your calculations assume that the speed increases along with the scaling of the resistance. However I think in this discussion we need to consider...
I don't have any real interest in building a wind turbine boat. I was just countering your more pessimistic estimates. It's a discussion. Anyway,...
It's quite possible that you can get good efficiencies from a wind turbine setup. Just looking up some numbers, aircraft propellers can get up to...
Why does it sound impossible? A conventional sailing boat can sail directly into the wind, it just does so by tacking. Essentially there is no...
There is never more thrust than drag. Newtons third law of motion.
I have both 'Sailing Theory and Practice', and 'The Aero-hydrodynamics of Sailing'. There is a bit of crossover between them. Aero-hydrodynamics...
We are in the hydrodynamics and aerodynamics section of the forum, so I thought we were discussing aerodynamics. My apologies. OK, so regarding...
A 15 second search on the internet found me this - [MEDIA]
Of course pressure differences occur. They occur due to changes in the velocity. Circulation theory is based on this. Referring back to...
Yes, it can. However, 100 years worth of experiments have shown that significant changes in volume or temperature do not occur, and significant...
This is true. But consider the case whereby a sail powered boat is tacking through 90 degrees. The sail powered boat would have to sail about 1.4...
Almost all of the literature I have read, and I have read a bit of it, state that sails work due to them developing a high pressure region of air...
Just because the unbound edge is acting as a free surface. It doesn't matter that it's at either the top or the bottom of the foil, it will affect...
Your experiment is a bit like a wind tunnel. If you had a wind tunnel that was closed on three sides, but open at the top or bottom, you wouldn't...
Either way, I think the fluid should be bounded both sides to properly represent a continuous fluid field.
I previously said "I suspect that if you summed the velocities around the foil and subtracted the free stream velocity, you would probably find a...
The origin of the pressure difference is implicit. Retarding the flow beneath the foil compresses the fluid the, creating a high pressure region....
To be clear, I'm talking about a hydrofoil working close to the water surface (free surface effect), which is different to an airfoil working...
Having read your paper, I find a number of assertions which appear to be unfounded. One of particular note is, quote: "The venturi is offered as...
