Our heavyweight helicopter equal in the world does not have
In Rostov started production of the most load-lifting rotary-wing car The Russian holding «Helicopt[...]
Stagnation
Another feature of the flow is that the air following the dividing streamline slows down as it approaches the wing, and if the wing is not swept it actually stops instantaneously on the surface before dividing. Because the particles are momentarily ‘stagnant’ at this position, it is known as a stagnation position.
It should be remembered, that in Fig. 1.13, we are looking at a twodimensional section. If we take a three-dimensional view, as in Fig. 1.14, then we need to consider imaginary stream-surfaces. It will be seen, that the dividing stream surface meets the wing section along a line just under the leading edge. The stagnation position, seen as a point in the two-dimensional section, is just an end-on view of this stagnation line.
If the wing is swept, then only the component of flow at right angles to the wing leading edge is stopped, and the line of contact is called a dividing attachment line.
|
Fig. 1.14 Stream surfaces In a three-dimensional view, the flow can be represented by stream surfaces |
|
Fig. 1.15 Pressure distribution around an aerofoil |
