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The German Zeppeins of World War I were dirigibles with the following typical characteristics:
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- Icebergs can be driven at substantial speeds by the wind.Let the iceberg be idealized as a large, flat cylinder, D >> L,with one-eighth of its bulk exposed, as in Fig.. Letthe seawater be at rest. If the upper and lower drag forcesdepend on relative velocities between the iceberg and thefluid, derive an approximate expression for the steady icebergspeed V when driven by wind velocity U.arrow_forwardThe large block shown is x = 72 cm wide, y = 54 cm long, and z = 9.0 cm high. This block is passing through air (density of air p = 1.43 kg/m³) at a speed of v = 8.61 m/s. Find the drag force F41 acting on the block when it has the velocity vj and a drag coefficient I = 0.812. V2 Fa.1 N %3D Find the drag force F42 acting on the block when it has the velocity vz with a drag coefficient I = 0.893. F42 N Find the drag force Fa.3 acting on the block when it has the velocity vz with a drag coefficient I = 1.06. F4.3 = N ENarrow_forwardFluid Mechanics Problem: A ship is 150 m long and has a wetted area of 5000 m2.If it is encrusted with barnacles, the ship requires 7000 hp to overcome friction drag when moving in seawater at 15 kn and 20oC. What is the average roughness of the barnacles? How fast would the ship move with the same power if the surface were smooth? Neglect wave drag. Note: Treat the ship hull as a flat plate. Use eq. 7.48b to find effective barnacle roughness height.Use equation (7.45) White for the drag coefficient CD = D/.5pV2A , where A is the hull (plate) area, to find the ship velocity for smooth plate.arrow_forward
- You are designing an airfoil for a new hobby RC plane. Because of your limited knowledge, you have mistakenly approximated your airfoil as an ellipse with a = 75mm and b = 12mm. Here, “a” is the depth of your wing and “b” is the thickness. Your plane travels through the air at approximately 20mph (8.9m/s). As it does so, skin friction produces a drag-induced heat of 800W on your wind, of length 1m. Properties of Air: k = 0.025 W/mK, Pr = 0.72, v = 1.847 x 10−5, u = 16.84 x 10−6, p = 1.2 kg/m3, B = 1/Tf (ideal gas), TInfinity = 25oC a) What is the Reynold’s number? Hint: “D” is taken to be the thickness for an elliptical crosssection. b) What is the Nusselt number? c) What is the convection coefficient? d) What is the average temperature of your wing? Assume an ellipse perimeter of approximately 200mm.arrow_forwardYou are designing an airfoil for a new hobby RC plane. Because of your limited knowledge, you have mistakenly approximated your airfoil as an ellipse with a = 75mm and b = 12mm. Here, “a” is the depth of your wing and “b” is the thickness. Your plane travels through the air at approximately 20mph (8.9m/s). As it does so, skin friction produces a drag-induced heat of 800W on your wind, of length 1m. Properties of Air: k = 0.025 W/mK, Pr = 0.72, v = 1.847 x 10−5, u = 16.84 x 10−6, p = 1.2 kg/m3, B = 1/Tf (ideal gas), TInfinity = 25oC a) What is the average temperature of your wing? Assume an ellipse perimeter of approximately 200mm.arrow_forwardTheory of Flight A- Airbus 320 fly in steady level flight with altitude 11000m, find the lift force required to steady level flight. At steady level flight aircraft has weight as (65000 kg), wing area is (124 m?), aircraft speed is (147 m/s) and lift coefficient is (1.3) Atmosphere data for 11000m shown in table below Туре of atmosphere layer Stratosphere Rang (m) Temperature gradient (a) k/m Temperature (k) 0-11000 -0.0065 288-216.6 Given data (R=287, g=9.81 m/s?, and po=1.225 kg/m³)arrow_forward
- The airplane as described has a stalling speed at sea level of 100 mph at the maximum take-off weight of 15,900 lb. The ambient air density at standard sea level is 0.002377 slug/ft3. Calculate the value of the maximum lift coefficient for the airplane.arrow_forwarda)What is the impact of increasing Reynolds number on skin friction and pressure drags over an airfoil? What can be happened for separation in this case? b) What is an adverse pressure gradient and where does it occur on an airfoil (show that on a sketch)? c) Why lift-to-drag ratio is an important parameter for an aircraft? d)How can changing in altitude affect the aircraft power required, PR? Show thatmathematically and graphically?arrow_forwardA light truck weighs 3,300 lb and is rated at 30 miles per gallon for 52 mph highway driving on level ground. Under those conditions, the engine must overcome air resistance, rolling resistance, and other sources of friction. Give your answers in the units shown. (a) The coefficient of drag is 0.55 at 52 mph, and the truck's frontal area is 28 ft?. What is the drag force on the truck? (Express your answer using three significant figures.) F = lb (b) How much power must the engine produce at 52 mph just to overcome air resistance? (Express your answer using three significant figures.) P = |hp (c) In part (b) how much gasoline would be consumed each hour (neglecting other frictional effects)? (Express your answer using three significant figures.) V = galarrow_forward
- Estimate the landing ground roll distance at sea level for the CJ-1. No thrust reversal is used; however, spoilers are employed such that L drag coefficient by 10 percent. The fuel tanks are essentially empty, so neglect the weight of any fuel caried by the airplane. The maximum lift coefficient, with flaps fully em- ployed at touchdown, is 2.5. 0. The spoilers increase the zero-lift,arrow_forwardA helicopter is hovering at an altitude where the density of air is 1.165 kg/m³. The helicopter rotor disc has a diameter of 9 m and is rotating at 466 rpm, with the blades having a chord of 0.16 m. Estimate the drag force in newtons per unit span along an elemental strip at the mid-span of the blade. You may assume the drag coefficient of the blade at the mid-span is 0.025.arrow_forwardA 5,000 lb airplane with wing area of 250 sq. ft and power available of 450 hp is at sea level flight standard condition. The airplane drag-to-lift relation is close to Co = 0.025 + 0.048 CL². What is the rate of climb (in feet per minute) at a flight speed of 180 miles per hour?arrow_forward
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