(Solved): Question 4 Part A. A laminar flow wind tunnel has a cylindrical test section that is 30 cm in diam ...

Question 4 Part A. A laminar flow wind tunnel has a cylindrical test section that is 30 cm in diameter and 80 cm in length. The air is at 20 °C. There is a uniform air speed of 2 m/s at the test section inlet. Assume that the kinematic viscosity v (= ?/p) of air at 20 °C is 1.516x10-5 m² /s. a. Calculate the Reynolds number (Rex) at the end of the test section. b. Estimate the displacement thickness at the end of the test section. c. Use conservation of mass to estimate the air speed at the end of the Part B. Figure 2 shows a water-jet engine that is able to develop both lift and thrust. While undergoing tests, it is held static below the surface of the sea. The engine takes in water at a uniform speed of 2 m/s through an intake of area 0.4 m² to a pump that forces out the water through a jet nozzle of area 0.04 m² angled downwards at 30° from the horizontal. In the questions that follow, ignore the effects of viscosity and gravity, and assume that the water flow is incompressible throughout. You may also assume that the water pressure at the inlet and outlet of the engine is the same. Water density is given as 1000 kg/m³. a. Define a suitable control volume around the component, and use this to determine the speed at which the water exits the jet nozzle. (8 marks) b. Determine the thrust (force towards the left) and the lift developed by the engine. (8 marks) 2m/s 0-4m² (3 marks) (3 marks) test section. (3 marks) Figure: 2 PUMP 0-04m² [Total: 25 marks]