Recent content by tsimon

Cheers!

So stagnation gives lower pressure? Makes sense for golf ball but not for airfoil as low pressure should be beneficial for an airfoil.

Great responce, thanks. I still (pardon me being a retard) having a hard time grasping why separation is negative for a golf ball. A detached flow filled with vortices should in my pov increase pressure and this should give less resistance for the ball.

A decrease in the airfoils ability to deflect the flow downward implies that the transverse (?) pressure gradient is smaller and thereby the pressure is higher

What I meant was if separation gives high pressure (as you wrote in your first responce) then separation on the backside of an golf ball would be beneficial. Finally I want to thank you for answering my questions.

Ok, so flow separation does not really mean that a volume is evacuated but rather that there is a circulation? so this is incorrect: http://upload.wikimedia.org/wikipedia/commons/8/8d/StallFormation.svg But if so, why would flow separation be negative for a golf ball? If separation increases...

Why does flow separation give less lift? A separated "suction side" would in my pov give zero pressure (which is the lowest possible). And low pressure on suction side is, of course, beneficial. I think I got it now; as the pressure can not drop further a increase in angle of attack will...

Wrong subforum?

Can somebody describe wave making resistance in terms of pressure distribution on a body (near or at a free surface)? Cheers, Simon

It is definitely not wrong, altough it doesn't explain where the pressures that gives the thrust are "operating" or how the pressure is created.

Hi! I have a question about how thrust is made from a turbojet engine. The most common explanation goes something like "As the fluid gets accelerated there is a net force". I don't think this explanation is either good nor rigorous. The force that accelerates the fluid is, of course, the...

Reading error, my bad.

I've experienced the opposite explanation, a net force is giving an acceleration. Maybe that is a simplified explanation, I'm not a physicist but an engineer. Or can this be cultural differences? I'f from Sweden.

Thank you, great contribution! Lets see if I got this: The lift is created by high pressure under and low pressure above the airfoil. If we take a look at what happends under the aifoil: The airspeed is reduced and redirected downwards, might be explained out of conservaty of mass(as in...

I don't really understand. A airfoil can produce lift at 0 degrees of attack right by the "Bernoulli effect"? If so, then there must possible for it to create work which is made on both the air and the aifoil itself?