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Unformatted text preview: EAS 4101 – Aerodynamics – Spring 2009 02/25/09 Exam #1 Name: ___________________________ 1 I. TRUE/FALSE (10 Points total – 1 point each) 1. Streamlines, pathlines, streaklines, and timelines are identical for steady flows. F 2. A streamline is a curve that is everywhere tangent to the instantaneous local velocity vector. T 3. In a Newtonian fluid, the relationship between an applied shear stress and the resulting deformation rate on the fluid is governed by a linear viscosity law. T 4. A natural extension of particle mechanics, the Eulerian method of fluid flow analysis focuses on material particles as they move through the flow. F 5. The deviatoric stress tensor consists of stresses associated with fluid motion. T 6. If an aircraft is moving with constant velocity, the lift force has the same magnitude as the drag force. F 7. Flow in a boundary layer is irrotational in the presence of a favorable pressure gradient. F 8. The leading edge of an airfoil is the forward most point on the mean camber line. T 9. The Kutta-Joukowski Theorem states that the lift per unit span is inversely proportional to circulation. F 10. The center of pressure is defined as 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. F II. FILL IN THE BLANK (20 Points total) 11. The ______ lateral ______ axis runs from wingtip to wingtip through the airplane’s ___________ COG __- ________. Motion about this axis is called _______ pitch ______ and is produced by deflection of the _______ elevators ________. ( 4 points ) 12. The two primary types of drag experienced by an aircraft in flight are ________ induced drag _______, a by- product of lift, and _______ parasitic drag _________, which is the air resistance produced by the airframe components. ( 2 points ) 13. Among the flow lines used to visualize the flow patterns, which ones have some “age” and thus a time history associated with them? _____________ pathlines and streaklines _____________ ( 2 points ) 14. The mathematical relation, __ gG ¡¢ ∙ £¤¥ ____ is the time rate of change of the flow property due to the movement of the fluid element in the flow field. Hint: this mathematical term is known as the convective derivative ( 1 point ) 15. (6 points) For each derivation of the steady Bernoulli equation, please list the appropriate assumptions: N.S. Equation Euler - S Energy Equation Inviscid Inviscid Inviscid Incompressible Incompressible Incompressible Irrotational Flow along a streamline Conservative Flow EAS 4101 Name: _____________________ 16. Answer the following questions pe angle of attack. (a) The value of α when lift equals symmetric airfoils, this occurs (b) One of the most important indi the lift coefficient, which occu (c) Above a certain α , stall occurs (a) – Aerodynamics – Spring 2009 02/25/09 Exam #1 _______ ertaining to the provided schematic of airfoil lift-coefficien ls zero is known as the ____________...
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- Spring '08
- Fluid Dynamics, Velocity, Incompressible Flow, Linear Momentum Equation