This set of Aerodynamics Questions and Answers for Entrance exams focuses on “The Kutta Condition”.
1. Is Kutta condition is applicable to solid bodies with sharp corners?
Explanation: The kutta condition is a principle in steady-flow fluid dynamics, especially aerodynamics that is applicable to solid bodies with sharp corners, such as the trailing edge of the airfoil. It is named for German mathematician and aerodynamicist martin Wilhelm kutta.
2. Is body with sharp trailing edge will create circulation?
Explanation: A body with sharp trailing edge which is moving through a fluid will create about itself a circulation of sufficient strength to hold the rear stagnation point at the trailing edge when the fluid is moved over the airfoil decrease in the crossectional area will create the circulation.
3. Is kutta condition refers to the flow pattern on the body?
Explanation: In fluid flow around a body with a sharp corner, the kutta condition refers to the flow pattern in which fluid approaches the corner from both directions, meets at the corner, and then flows away from the body. None of the fluid flows around the corner attached to the body.
4. Is lift is created on the airfoil using kutta condition?
Explanation: The kutta condition is significant when using the kutta joukowski theorem to calculate the lift created by an airfoil with a cusped trailing edge. The value of circulation of the flow around the airfoil must be that value, which would cause the kutta condition to exist.
5. Is kutta condition apply to oval shaped body?
Explanation: When a smooth symmetric body, such as a cylinder with oval cross-section moves with zero angle of attack through a fluid it generates no lift. There are two stagnation points on the body one at the front and the other at the back. Since no lift will be generated by the cylinder at zero angle of attack.
6. How many stagnation points on the oval cylinder with non-zero angle of attack?
c) More than zero
Explanation: An oval cylinder moves with a non-zero angle of attack through the fluid there are still two stagnation points on the body. One on the underside of the cylinder, near the front edge and the other on the top side of the cylinder near the back edge. The circulation around this smooth cylinder is zero and no lift is generated, despite the positive angle of attack.
7. Is the airfoil with a sharp trailing edge move with a positive angle of attack?
Explanation: The airfoil with a sharp trailing edge begins to move with a positive angle of attack through air, the two stagnation points are initially located on the underside near the leading edge and on the topside near the trailing edge, just as with the cylinder, as the air passing the underside of the airfoil reaches the trailing edge, it must flow around the trailing edge on the top side of the airfoil.
8. Vortex flow occurs at ___________
a) Leading edge
b) Trailing edge
d) Chamber line
Explanation: Vortex flow occurs at the trailing edge and because the radius of the sharp trailing edge is zero, the speed of the air around the trailing edge should be infinitely fast, real fluid cannot move at infinite speed, they can move extremely fast finite speed.
9. Is high airspeed around the trailing edge causes strong viscous forces?
Explanation: The high airspeed around the trailing edge causes strong viscous forces to act on the air adjacent to the trailing edge of the airfoil and the result is that a strong vortex accumulates on the topside of the airfoil, near the trailing edge.
10. How starting vortex is formed?
a) As the airfoil begins to move vortex are formed
b) As the airflows on the airfoil vortex are formed
c) As the airfoil moves against the relative wind vortex are formed
d) As the airflows on the circular body vortex are formed
Explanation: As the airfoil begins to move it carries this vortex, known as the starting vortex along with it, pioneering aerodynamicists were able to photograph starting vortices in liquids to confirm their existence. The vorticity in the starting vortex is matched by the vorticity in the bound vortex in the airfoil.
11. How airfoil increases its speed?
a) Flow over the topside
b) Flow over the leading edge
c) Flow over the bottom side
d) Flow over the trailing edge
Explanation: As the vorticity increases the bound vortex and also progressively increases and causes the flow over the topside of the airfoil to increase in speed. The starting vortex is soon cast-off the airfoil and is left behind, spinning in the air, where the airfoil left it.
12. How stagnation point on the topside of the airfoil reaches the trailing edge?
a) Due to viscous forces
b) Due to surface forces
c) Due to pressure forces
d) Due to drag forces
Explanation: The stagnation point on the topside of the airfoil then moves until it reaches the trailing edge. The starting vortex eventually dissipates due to viscous forces. As the airfoil continues on its way, there is a stagnation point at the trailing edge. The flow over the topside of the airfoil conforms to the upper surface of the airfoil.
Sanfoundry Global Education & Learning Series – Aerodynamics.
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