Calculate the drag forces on a 1/200 scale model of the Willis Tower that is tested in a large water flume under conditions corresponding to those in problem 9.89. Ignore any free surface effects and assume dynamic similarity and that the drag coefficient is unchanged.
The Willis Tower (formerly the Sears Tower) in Chicago is 1454 ft tall. Assuming that it is a tall rectangle with a square base of 120 ft sides, calculate the maximum drag force on the building and the force when the wind is along the diagonal of the structure as a function of wind speed from Beaufort Wind Scales of strong breeze (28 mph) to hurricane (75 mph). Assuming that the wind field is uniform, calculate the moment about the base of the Tower also.
Want to see the full answer?
Check out a sample textbook solutionChapter 9 Solutions
Fox and McDonald's Introduction to Fluid Mechanics
Additional Engineering Textbook Solutions
Engineering Mechanics: Dynamics (14th Edition)
Heating Ventilating and Air Conditioning: Analysis and Design
Automotive Technology: Principles, Diagnosis, And Service (6th Edition) (halderman Automotive Series)
Fundamentals Of Thermodynamics
Fundamentals of Heat and Mass Transfer
Engineering Mechanics: Statics & Dynamics (14th Edition)
- A wind tunnel is being used to study the aerodynamics of a full-scale model rocket that is 30 cm long. Scaling for drag calculations are based on the Reynolds number. The rocket hasan expected maximum velocity of 190 km/h. What is the Reynolds number at this speed? Assume ambient air is at 20°C. The wind tunnel is capable of speeds up to 160 km/h; so an attempt is made to improve this top speed by varying the air temperature. Calculate the equivalent speed for the wind tunnel using air at 5°C and 65°C. Would replacing air with carbon dioxide provide higher equivalent speeds?arrow_forwardThe drag on a sonar transducer is to be predicted, based on wind tunnel test data. The prototype, a 1 ft diameter sphere, is to be towed at 5 knots (nautical miles per hour) in seawater at 20°C. The model is 6 in. in diameter. Determine the required test speed in air at 20°C. If the drag on the model at test conditions is 5.58 lbf, estimate the drag on the prototype.arrow_forwardA flagpole 16 m high has the shape of a cylinder 100 mm in diameter. The air temperature is 30°C and the atmospheric pressure is 101 KPaa. With what speed is the air blowing against the pole if the moment developed at the base is 2.7 KN.m? The drag coefficient is 1.3.arrow_forward
- Problem 4. A cork ball (SG = 0.21) with a diameter of D = 0.30 m is tied to an object on the bottom of a river as %3D shown. (a) For an angle of B = 30°, estimate the speed of the river current neglecting the weight of the cable and the drag on it. (b) Briefly discuss how the angle changes for a range of speeds from 0.4 m/s to 10 m/s. Uarrow_forwardThe drag polar equation of a light airplane in clean configuration can be written as Cp = 0.358 + 0.0405 C₁². It has a weight of 18,681 N. The wing area is 14.41 m². Calculate the minimum power required in watts. (Round off answer with no decimal places, No units, No commas) Answer given: 1461792 A 5,000 lbs. aircraft has an excess power of 75 hp at sea level. If the service ceiling is 3,657.6 m, determine the time to climb from sea level to absolute ceiling in minutes. (Round off answer with no decimal places. No units, No commas) Answer given: 17arrow_forwardThe main cross-cable between towors of a coastal suspension bridge is 27.9 cm in diameter and 60 m long. Estimate the total drag force in (N] on this cable in crosswinds of 67.5 km/h. Assume the temperature of air is 15°C. Assume the drag coefficient is 1.5. The tolerance of your answer is 2%. PROPERTIES Air at 15"C Density = 123 kglm Dynamic viscosity 1.79 x 10 Ns/m?arrow_forward
- The drag characteristics of an aircraft must be determined by a test of a model subjected to a wind tunnel operated at an absolute pressure of 1300 KPa. If the prototype will be used in standard air at 385 km/hr, and the corresponding speed of the model does not differ by more than 20% from the speed of the prototype (so that the compressibility effects are ignored), what range of length scales can be used if the Reynolds number remains similar? Assume that the viscosity of the air is not affected by the pressure, and that the air temperature in the wind tunnel is equal to the air temperature to which the prototype will be subjected.arrow_forwardQ1/ Boeing 737 - 60 flies at altitude 15000m above sea level with speed 85 m/s and total drag coefficient equal to ( 5) . Find the drag force at this fly condition. Given data IR=287,g=9.81 m/s2 , rho O=0.3648 kg/m2 and wing area = 120m^ ^ 2^ *arrow_forwardA thin sheet of fiberboard weighs 90 N and lies on a rooftop,as shown in Fig. . Assume ambient air at 20°Cand 1 atm. If the coefficient of solid friction between boardand roof is σ ≈ 0.12, what wind velocity will generateenough fluid friction to dislodge the board?arrow_forward
- The original Flettner rotor ship was approximately 100 ftlong, displaced 800 tons, and had a wetted area of 3500 ft2. Assketched in Fig. , it had two rotors 50 ft high and 9 ft indiameter rotating at 750 r/min, which is far outside the range. The measured lift and drag coefficients for eachrotor were about 10 and 4, respectively. If the ship is mooredand subjected to a crosswind of 25 ft/s, as in Fig. whatwill the wind force parallel and normal to the ship centerlinebe? Estimate the power required to drive the rotors.arrow_forwardThe drag characteristics of an aircraft must be determined by a test of a model subjected to a wind tunnel operated at an absolute pressure of 1300 KPa. If the prototype will be used in standard air at 385 km/hr, and the corresponding speed of the model does not differ by more than 20% from the speed of the prototype (so that the compressibility effects are ignored), what range of length scales can be used if the Reynolds number remains similar?arrow_forwardA closed-loop wind tunnel has a test section of cross-section W =3 ft by H =5 ft and length L =4 m. An aerofoil with 21% thickness to chord ratio and a chord length of 0.52 m is mounted vertically in the test section and spans the entire height. If the measured lift and drag coefficients are C; = 0.325 and Ca =0.0071, what is the lift coefficient after correcting for solid blockage, wake blockage and streamline curvature? Give your answer to 3 decimal places.arrow_forward
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY