Concept explainers
The total drag on an airfoil can be estimated by
FIGURE P16.28
Plot of drag versus velocity for an airfoil.
where
(a)
(b) In addition, develop a sensitivity analysis to determine how this optimum varies in response to a range of
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EBK NUMERICAL METHODS FOR ENGINEERS
- 2. The table below shows experimental data for the shape and pressure distribution on the upper and lower surface of an airfoil at zero angle of attack. X 0 0.25 0.5 0.75 1 Yu 0 0.0952 0.0922 0.0588 0 Fx = dYu dx 5 Y₁ 0 -0.0254 -0.0144 -0.0052 0 PL Pd) d: dx Y = Yu (x) Calculate the drag and lift force on the airfoil by numerically evaluating the integrals = S₁² ( P₂₁ = ['(P₁ - F (P₁ - Pu)dx 0 y = Y₂ (x) Pu 1.000 -1.640 -0.786 -0.212 0 Fy x Pi 1.000 0.589 0.426 0.322 0 Use finite difference approximations of the derivatives and the composite Simpson's rule to evaluate the integrals. Hint: Use central differences to estimate the derivatives wherever possible since they are more accurate than forward or backward differences.arrow_forward#4 1.11 For a small particle of styrofoam (1 lbm/ft) (spherical, with diameter d = 0.3 mm) falling in standard air at speed V, the drag is given by FD-3mVd, where is the air viscosity. Find the maximum speed starting from rest, and the time it takes to reach 95 percent of this speed. Plot the speed as a function of time. s) Answer: (Vmax=0.0435",t=0.0133 Sarrow_forwardLong flights at midlatitudes in the Northern Hemisphere encounter the jet stream, an eastward airflow that can affect a plane's speed relative to Earth's surface. If a pilot maintains a certain speed relative to the air (the plane's airspeed), the speed relative to the surface (the plane's ground speed) is more when the flight is in the direction of the jet stream and less when the flight is opposite the jet stream. Suppose a round-trip flight is scheduled between two cities separated by 3200 km, with the outgoing flight in the direction of the jet stream and the return flight opposite it. The airline computer advises an airspeed of 810 km/h, for which the difference in flight times for the outgoing and return flights is 72 min. What jet-stream speed is the computer using?arrow_forward
- 5.25 A finite wing of area 1.5 ft² and aspect ratio of 6 is tested in a subsonic wind tunnel at a velocity of 130 ft/s at standard sea-level conditions. At an angle of attack of -1°, the measured lift and drag are 0 and 0.181 lb. respectively. At an angle of attack of 2°. the lift and drag are measured as 5.0 and 0.23 lb, respectively. Calculate the span efficiency factor and the infinite-wing lift slope.arrow_forwardYour plane has a lift to drag ratio of ŋ = 14.4 at a 10° angle of attack and mass of 3500kg. The wing area is 24m2. What is your Lift ifyour plane is oriented 13° from the horizontal at this particular angle of attack? *make sure you define all the variables correctly. 21. %3Darrow_forwardad/quiz/attempt.php?attempt%3D173629 O e 832.56000 When tested in water at 20°C (density of 998 kg/m3 and viscosity of 0.001 kg/m.s) flowing at 2 m/s, an 8-cm- diameter sphere has a measured drag of F=164.7 N. What will be the drag force on a 1.5-m-diameter weather balloon moored in sea-level standard air (density of 1. 2255 kg/m3 and viscosity of 1.78E-05 kg/m s) under dynamically similar conditions? ered 3.00 tion Select one: O a 108.58506 Ob. 42.70506 Oc. 141.52506 Od. 75.645063 Oe. 9.76506 The uniform 5-m-long round wooden rod is tied to the bottom by a string. find the tension in the string. The fluid specific gravity S=0.7. ed 00 on D=8 cm Fluid Darrow_forward
- An airplane, weighing 10 kN (including cargo and passengers) has an area (chord x span) of 20 m². What is the stall speed, in kph? The wing characteristics follows the shape of NACA 2412 with lift properties shown in the graph. Assume that the density air is 1.2 kg/m³. 2.00 NACA 2412 section CL 1.50 1.00 0.50 NACA 0012 section -0.50 5 10 15 Angle of attack, a, degrees Answer: a 20arrow_forward1. The given information is as follows: Cd=1.4 (coefficient of drag) ¥=10 ft/sec (velocity) Ƴ=62.4 #/ft3 g=32.3 ft/sec2 a. What is the water pressure in PSF against the obstruction? b. If the pier is 6 ft wide and 14 ft deep, what is the Resultant Pressure on the WHOLE obstruction? c. If the obstruction is fixed into the bottom of the river (mud line), what is the bending moment at the mudline on the obstruction?arrow_forwardC1 (a) A plate 0.05mm distant from a fixed plate moves at 1.15 m/s and required a force per unit area of 2.2 N/m2 to maintain this speed with using an oil of specific gravity 0.75. Find the dynamic viscosity and kinematic viscosity of the fluid between the plates. C1 (b) Calculate the specific weight, density, and the specific gravity of a liquid having a volume of 665000 cm3 and weight of 72 kN find : C1 (a) 1_The dynamic viscosity of the fluid (in Centipoise) 2_The kinematic viscosity of the fluid (in stokes) C1 (b) 3_Specific Weight in (N/m3) 4_Density of liquid (in kg/m3) 5_Specific gravity of liquidarrow_forward
- 6.10 A sphere advancing at 1.5 m/s in a stationary mass of water experiences a drag of 4.5 N. Find the flow velocity required for dynamic similarity of another sphere twice the diameter, placed in a wind tunnel. Calculate the drag at this speed if the kinematic viscosity of air is 13 times that of water and its density is 1.25 kg/m³. Ans. (9.75 m/s, 0.951 N)arrow_forward1. An airplane weighs 36,000 lb. and has a wing area of 450 fte. The drag equation is C, =0.014 + 0.05C} . It is desired to equip this airplane with turboprop engines with available power such that a maximum speed of 602.6 mph at sea level can be reached. The available power is assumed to be independent of flight speed. Calculate the maximum rate of climb and the speed at which it occurs. Given: W = 36,000 lb S = 450 ft² C, = 0.014+0.05C V = 602.6 mph max THPy = cons tan t THP AV constant Max EHP Point of THP, REQD. Flisht Speed. V Vmax 602.6 mph Required: Max R.C. and Vmax R.C. Horsepower, hparrow_forwardIf your lift to drag ratio is 15 for airline A flight and the airplane weighs 15,000-lb for L/Dmax, what’s the speed for L/Dmax at 22,500 lbs.?arrow_forward
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