Even here at MIT, there are advocates both strongly for and against the use of this equation. Simple and neat, the application of the Bernoulli equation, however, requires the flow to be: Steady Incompressible, and Frictionless; Furthermore, there can be no energy sources or sinks along the streamline. The Bernoulli equation is applied along a streamline, taking the form:. Take point 1 to be at a point on the streamline far in front of the wing see Figure 7.
Take point 2 to be at a point above the curved surface of the wing, outside of the boundary layer. It is assumed that compared to the other terms of the equation, gz 1 and gz 2 are negligible i. Thus, Equation 1 becomes:. For the second case, take point 1 to be again at a point on the streamline in front of the wing. Since the values for P ambient and v ambient are the same as for the first case, the constant from Equation 2 is also assumed to be the same.
Take point 2 to be at a point below the wing, outside of the boundary layer. With the same assumptions as in the first case, Equation 1 and 2 become:. Since the velocity of the fluid below the wing is slower than the velocity of the fluid above the wing, to satisfy Equation 3, the pressure below the wing must be higher than the pressure above the wing.
In a qualitative look at Euler's Equations, the movement of the fluid flow around the curved upper surface of the wing may be likened to that of a car going around a bend. Similarly, as the fluid particle follows the cambered upper surface of the wing, there must be a force acting on that little particle to allow the particle to make that turn.
This force comes from a pressure gradient above the wing surface. Starting at the surface of the wing and moving up and away from the surface, the pressure increases with increasing distance until the pressure reaches the ambient pressure.
Thus, a pressure gradient is created, where the higher pressures further along from the radius of curvature push inwards towards the center of curvature where the pressure is lower, thus providing the accelerating force on the fluid particle. Thus due to the curved, cambered surface of the wing, there exists a pressure gradient above the wing, where the pressure is lower right above the surface.
Assuming a flat bottom, the pressure below the wing will be close to the ambient pressure, and will thus push upwards, creating the lift needed by the airplane. At angles of attack below around ten to fifteen degrees, the lift increases with an increasing angle. However, if the angle of attack is too large, stalling takes place. Stalling occurs when the lift decreases, sometimes very suddenly. The phenomena responsible for stalling is flow separation see Figure 9. Flow separation is the situation where the fluid flow no longer follows the contour of the wing surface.
Fluid particles flowing along the top of the wing surface experience a change in pressure, moving from the ambient pressure in front of the wing, to a lower pressure over the surface of the wing, then back up to the ambient pressure behind the wing. You are commenting using your Twitter account.
You are commenting using your Facebook account. Notify me of new comments via email. Notify me of new posts via email. Minimize airfoil audio delay Posted: June 1, Author: nicolasamiot Filed under: osx Tags: airfoil , audio , osx 19 Comments Before Apple introduces an easy airplay management directly into osX with Mavericks, Rogue Amoeba Airfoil was the most convenient solution to stream your music on your airplay compatible speakers.
Just before the explanation I would precise the common tagline of every hack method : Please note that I do not take any responsibility if something goes wrong with my method, you do it at your own risk for your software and hardware parts!
Airfoil now streams your audio outputs with a very low latency! Like this: Like Loading Jesse Schoff jesseschoff says:. December 30, at pm.
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Storm Brewer says:. Airfoil automatically works to keep any and all devices to which it's streaming in sync with one other. Most users should have no need to manually adjust the sync offset.
In rare cases, however, a device may have a separate delay which causes it to fall out of sync. If a speaker has an unexpected amount of additional latency, audio may not be heard in perfect sync. You can correct this using the controls in Airfoil's "Advanced Speaker Options" window.
The controls in the "Advanced Speaker Options" window provide a constant latency adjustment, and are remembered between launches of Airfoil. With a bit of trial and error, you may be able to adjust settings to get perfect sync. If a device has a fluctuating amount of latency, these sliders won't be able to correct things permanently.
This can occur when there's an issue with the local network, interference from other sources, or an issue with the device itself. When these problems arise, it may be impossible to sync multiple outputs.
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