Prepare to your applied aerodynamics examination with these computational exercises.
Consider a normal shock wave with the pressure ratio P2/P; equals twice the density ratio P2/p1. The downstream Mach number of the wave is:
0.527
An expansion wave is created by a deflection angle of 10 degrees at a supersonic stream with Mach number of 2 and a pressure ratio P2/P1= 1/3. The Mach number after the wave is:
2.71
Using the linearized theory, Calculate for the mach number for a double wedge section with zero-degree angle of attack if its wedge angle is five degrees and its drag coefficient is 0.0176.
Answer: 1.9989
Consider an airfoil in a flow of air, where far ahead of the airfoil (the freestream), the pressure, velocity, and density are 2116 psf, 500 mph, and 0.002377 slugs/ft3, respectively. At a given point A on the airfoil, the pressure is 1497 psf. What is the velocity at point A? Assume isentropic flow. For air Cp = ft.lb/slug R.
Answer: 1061 ft/s
Consider the flow of air over a small flat plate that is 5 cm long in
the flow direction and | m wide. The free-stream conditions
correspond to standard sea level, and the flow velocity is 120
m/s. Assuming laminar flew, calculate the boundary layer
thickness at the-downstream edge (the trailing edge).
Answer: a. 4.06 x 10-4 m
An airplane whose wing loading is 8 lb. per sq. ft. is flying level at an airspeed of 100 miles per hour. If at angle of zero lift, C am, = —0.067, what is the center of pressure?
During climb, the airplane accelerates at 48 fi/s*. If the weight of the airplane is 3,800 Ib, what is the load factor?
Answer: 2.5
A convergent duct has an inlet area of 5 sq. ft. Air enters the duct at 26 meters/ sec and exits at 32 meters/sec. What is the exit area in sq. ft?
Answer: 41 ft^2
A pipe is tapering in size, diminishing by 0.1 square ft per foot run. What is the change in velocity per foot run where the pipe is 4 square ft in cross section? If the velocity there is 90 ft per second, is the velocity increasing or decreasing?
Answer: dV/dS = 2.25 fps per ft, increasing
A circular pipe, 100 ft long tapers from 3 ft in diameter at one end to 2 ft in diameter at the other. Fluid is flowing from the bigger toward the smaller. What is the rate of increase in velocity per foot run at the entrance if the velocity there is 80 ft per second?
Answer: dV/dS = 0.444 fps per ft
Air having the standard sea level density has a velocity of 100 fps at a section of a wind tunnel, at another section having an area half as great at that at the first section the flow velocity is 400mph. What is the density at the second section?
Answer: p2 = 0.000810 slugs per cu ft.
A venturi tube in 6 in. in diameter at the entrance, where the pressure is 10 Ib./in2 (gage). The throat is 4 in. in diameter, there the pressure is 6 Ib./in2 (gage). What is the flow of water?
Answer: Q = 2.37 ft3/s
For the flow in the above problem, what is the pressure on the cylinder surface at a 90° arc from the direction of airflow?
Answer: P = 2,081.14 lb per sq ft
A cylinder 30 in. in diameter rotates in an airstream of 70 mph. It develops 40Ib. of lift per foot length. What is the rotational speed?
Answer: N = 2.66 rev/sec
Find the velocity at which test should be run in wind tunnel on a model wing of 0.10 m chord in order that RN, shall be the same as for a wing with a 1.22 m chord at 44.7 m/s. Air under standard conditions in both cases.
Answer: VM = 545.34 mls
An airplane is flying at a density altitude of 4500m at an ambient temperature of 234K. If the wing chord is 1.83 m and the equivalent airspeed ie(130 meter per Second, what is the overall Reynolds number of the wing?
Answer: RN = 12,177,241.22
What is the total force of a 45-mph wind on a hangar door 40 ft by 25ft?
Answer: F = 6,626.70 lb
A stream of air 60 ft. wide and 8 ft. high is moving horizontally at a speed of 100 mph. What force is required to deflect it downward 10° without loss in speed.
Answer: F = 4,278.18 1b
An Airplane is flying at 500knots in air at -50°F. What is the critical Velocity?
Answer: 969.38 ft/s
An airplane is flying at an altitude of 3,500m at an airspeed of 300 mis. Find the critical speed, critical pressure and critical pressure coefficient.
An airfoil has a lift-curve slope of 6.3 per radian and angle of zero lift of -2 deg. At what angle of attack will the airfoil develop a lift of 140lb/ft at 100mph under standard sea level conditions? Assume c = 8ft.
Answer: a = 4.22 deg.
An a/p weighing 5,000 Lb is flying at seal-level w/ a velocity of 200 mph. At this velocity, the lift-to-drag ratio is at max. The wing area and aspect ratio are
200 ft? and 8.5, respectively. The Oswald’s efficiency factor is 0.93. Calculate the drag of the a/p.
Answer: D = 98.4 lb
Consider an experimental a/p w/ a wing area of 200 ft^2? and AR of 8.5. The said a/p is flying at min power required, SSLC, and has a zero-lift drag of 18.5 lb. Determine the induced drag at this min power required condition.
Answer: D = 55.5 lb
A twin-jet a/p has a max ROC of 179 fps at S.L.& a max ROC of 30.1 fps at 60,000’ altitude. Estimate: (i) the absolute & service ceiling, (ii) the time-to-climb from 10 000 to 30 000 ft altitude.
The max ROC ofan alp is given by the expression – ROC max = 850 — = h (“in fom). Compute the climbing time from 300’ up to its service ceiling.
Answer = 25.32 min
An a/p to perform a horizontal level-turn w/ a 120 m radius & velocity of 53 = will have a load factor of?
Answer: 2.58