EAS 4101  Aerodynamics – Spring 2004
3/3/04, Exam #1
Name: _____________key___________
1
Questions:(45 points total, 3 points each, unless otherwise marked)
1.
What is the definition of the center of pressure
for an airfoil?
The point on an airfoil about which the aerodynamic moment due to the distributed pressure load
is zero.
2.
What is the definition of the aerodynamic center
for an airfoil?
The point on an airfoil about which the aerodynamic moment due to the distributed pressure load
is not a function of the angle of attack.
3.
What is the velocity boundary condition
for a solid surface for an inviscidflow problem?
Normal velocity is zero, but there is slip!
4.
State the 3 methods (and their respective assumptions) discussed in class of deriving
Bernoulli’s equation
(6 points)
.
•
Inviscid, incompressible and along a stream line via EulerS equation
•
Inviscid, incompressible and irrotational via Cartesian Euler equation
•
Conservative flow via energy equation
5.
For inviscid flow around a bend, does the pressure increase, decrease, or remain the same in
the outward direction from the bend (or radius of curvature is increasing)?
Pressure will increase via EulerN equation
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View Full DocumentEAS 4101  Aerodynamics – Spring 2004
3/3/04, Exam #1
Name: _____________key___________
2
Questions continued: (45 points total, 3 points each, unless otherwise marked)
6.
What are the conditions under which both the streamfunction and the velocity potential
identically satisfy Laplace’s equation for a spherical coordinate system
?
2D (axisymmetric), incompressible, and irrotational.
Conservation of mass is identically
satisfied.
7.
In ideal flow, it is common to employ superposition solutions of various individual solutions
to Laplace’s equation in terms of the streamfunction and/or velocity potential.
Is it also valid
to superimpose pressure fields of each individual solution? Please justify your answer
mathematically and/or physically.
No, the pressure fields are nonlinearly related to the velocity fields via Bernoulli’s equation in
ideal flow.
8.
List and explain the origins of the two types of drag acting on a 2D bluff body
1)
Skin friction drag due to viscous wall shear stress.
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 Spring '08
 Sheplak
 Fluid Dynamics, Velocity, Ideal Flow, Vθ, κ cosθ

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