HWset7-S2011 - ASE320 Homework set# 7 Due:...

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Unformatted text preview: ASE320 Homework set # 7 Due: April 12, 2011 1.) The combination of a vortex with a sink can be used to simulate a tornado as is shown in the following illustration. If the circulation about the tornado is K = 8500m2/s and the pressure at r = 40m is 2200Pa less than the far ­field (ambient) pressure. Estimate a. the sink strength “ ­q” b. the pressure at r = 15m c. the angle β at which the streamlines cross the circle at r=40m Assume that the flow is inviscid and at sea level conditions. 2.) Two ­dimensional lift ­drag data for the NACA 2412 airfoil with 2 percent camber may be curve fitted accurately by: CL=0.178 + 0.109α – 0.00109α2 and CD=0.0089 + 1.97E ­4α + 8.45E ­5α2 – 1.35E ­5α3 + 9.92E ­7α4, with α in degrees in the range  ­4o < α < +10o. Compare: a. The lift curve slope. b. The angle of zero lift with theory: CL=2Π sin(α + β). c. Prepare a lift ­drag polar plot (CD vs. CL). 3.) The Boeing 727 airplane has a gross mass of 55,000kg, a wing area 110m2, and an aspect ratio of 6. It is fitted with two turbofan engines and cruises at 237m/s at a standard altitude of 10km. Assume for this problem that its airfoil is the NACA 2412 section described in the previous problem. If we neglect all drag except the wing, what thrust is required from each engine for these conditions? 4.) A freshwater boat of mass 400kg is supported by a rectangular hydrofoil of aspect ratio 8, 2% camber and 12% thickness. If the boat travels at 7m/s and α = 2.5o, estimate: a. The chord length b. The power required if CD∞ = 0.01 c. Top speed if engine delivers 20hp to the water. ...
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