Circulation Flashcards
Define lift per unit length due to circulation for any body in a 2D flow.
L = – rho * velocity * gamma, where gamma = circulation.
For a cylinder in a flow, describe the effect of rotating the cylinder.
The velocity on the side rotating with the flow increases, and the velocity on the side rotating against the flow decreases.
Define lift per unit length due to circulation for any body in a 3D flow.
L_effective = – rho * velocity_effective * gamma, where gamma = circulation.
What does the air at the TE do for ideal flow and on which surface?
Air on the pressure surface will reach the TE and turn around it, against the mean flow direction.
What does the air at the TE do for real flow and on which surface?
Air on the pressure surface reaches the TE, tries to turn around it. It can’t due to the p gradient, and it separates. Creates a starting vortex.
What does the starting vortex induce?
It must have a reaction, so circulation is created to balance it.
How does the starting vortex satisfy the Kutta Condition?
It aligns the separation point with the TE.
What effect does circulation have on an aerofoil?
It causes the velocity on the suction side to increase, and on the pressure side to decrease. This is what creates the p difference.
What effect does increasing circulation have on the front stagnation point?
It moves counter to the circulation.
