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Unformatted text preview: EAS 4101  Aerodynamics – Spring 2005 2/21/05, Exam #1 Name: _____________key___________ 1/10 Questions: (30 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. State the 3 methods (and their respective assumptions) discussed in class of deriving Bernoulli’s equation • Inviscid, incompressible and along a stream line via EulerS equation • Inviscid, incompressible and irrotational via Cartesian Euler equation • Conservative flow via energy equation 4. 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 EAS 4101  Aerodynamics – Spring 2005 2/21/05, Exam #1 Name: _____________key___________ 2/10 Questions continued: (30 points total, 3 points each, unless otherwise marked) 5. 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. 6. Explain when (i.e., list assumptions) d’Alembert’s paradox is valid and physically why it is expected? d’Alembert’s paradox is valid for 2D, inviscid flows and results in zero drag. This is expected because viscous forces result in skin friction at the body and are responsible for flow separation. 7. Describe the kinematic decomposition of a fluid flow as discussed in class. What are the four components and how do the assumptions of ideal flow affect their values? ( 6 points) 1) Pure translation: ideal flow assumptions do not limit this component. 2) Pure rotational: the assumption of irrotational flow results in this component being zero 3) Dilation: the assumption of incompressibility results in this component being zero 4) Shear strain: the assumption of inviscid results in this component being zero EAS 4101  Aerodynamics – Spring 2005 2/21/05, Exam #1 Name: _____________key___________ 3/10 Questions continued: (30 points total, 4 points each, unless otherwise marked)...
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This note was uploaded on 09/05/2011 for the course EAS 4101 taught by Professor Sheplak during the Spring '08 term at University of Florida.
 Spring '08
 Sheplak

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