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Chapter Six – Fluid Dynamics

Gases and liquids are considered to be fluid in nature. This chapter is all about the study of fluids. To study the motion of fluids two equations are used named as equations of continuity and Bernoulli’s equation.
In fluids a retarding force exist known as drag force, which opposes the motion of object in fluids. Drag force also increases with increase in speed of object. Terminal velocity is the maximum velocity of an object falling vertically downward.
Ideal fluid is in-compressible and non-viscous. Smooth flow of fluid is laminar flow and disordered flow of fluid is turbulent flow.Law of conservation of mass is used in equation of continuity and law of conservation of energy is used in bernoulli’s equation.In a pipe,as speed of fluid increases,pressure decreases this relation is known as venturi relation.

Q 6.1: Certain globular protein particle has a density of 1246 kg/m^3 it falls through pure water (viscosity = 8 x〖10〗^(-4) Ns/m^2) with a terminal speed of 3cm/h. Find the radius of the particle.

Q 6.2: Water flows through a hose internal diameter is 1cm, at a speed of 1m/s what should be the diameter of the nozzle if the water is to emerge at 21 m/s.

Q 6.3: The pipe near the lower end of a large storage tank develops a small leak and a stream of water shoots from it. The top of water tank is 15m above the point of leak. (a) With what speed does the water rush from the hole? (b) If the hole has an area …

Q 6.4: Water is flowing smoothly through a closed pipe system. At one point the speed of water is 3m/s while at another point 3m higher, the speed is 4m/s. If the pressure is 80kPa at the lower point what is the pressure at the upper end?

Q 6.5: An air plane wing is designed so that the sped of air across the top of the wing is 450m/s, the speed of air below the wing is 410m/s. What is the pressure difference between the top and bottom of the wing? (Density of air = 1.29 Kg/m^3)

Q 6.6: The radius of the aorta is about 1cm and the blood flowing through it has a speed of about 30cm/s. Calculate the average speed of the blood in the capillaries, using the fact that although each capillary has a diameter of about 8 x (10)^(-4) cm, there are literally millions of them so …

Q 6.7: How large must a heating duct be if air moving 3m/s along it can replenish the air in a room of 3000 m^3 volumes every 15 min? Assume the air’s density remains constant.

Q 6.8: An airplane design calls for a lift due to the net force of the moving air on the wing of about 1000N/m^2 of wing area. Assume that air flows past the wing of an air craft with streamline flow. If the speed of flow past the lower wing surface is 160 m/s, what …

Q 6.9: What gauge pressure is required in the city mains for a stream from a fire hose connected to the mains to reach a vertical height of 15m?