Q. Local skin friction coefficient is given by

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Q. Air at 25 degree Celsius flows over a flat surface with a sharp leading edge at 1.5 m/s. Find the boundary layer thickness at 0.5 from the leading edge. For air at 25 degree Celsius, kinematic viscosity = 15.53* 10n¯⁶ m²/s

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Q. A plate 0.3 m long is placed at zero angle of incidence in a stream of 15 degree Celsius water moving at 1 m/s. Find out the stream wise velocity component at the mid-point of the boundary layer. For water at 15 degree Celsius

p = 998.9 kg /m³
µ = 415.85 * 10¯² kg/hr m

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Q. Glycerin at 10 degree Celsius flows past a flat plate at 20 m/s. Workout the velocity components at a point P(x, y) in the fluid flow where

x = 2 m from the leading edge of the plate
y = 5 cm from the plate surface

For glycerin at 10 degree Celsius, kinematic viscosity = 2.79 * 10¯³ m²/s

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Q. The boundary layer thickness is taken to be at a distance from the plate surface to a point at which the velocity is given by

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Q. What is the value of thickness of the boundary layer at leading edge of the plate?

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Q. The entrance length required for the flow to become fully-developed turbulent flow is dependent on

(i) Surface finish

(ii) Downstream conditions

(iii) Fluid properties

Identify the correct answer

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Q. The transition from laminar to turbulent pattern of flow occurs at values of Reynolds number between

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Q. The pattern of flow in the boundary layer is judged by the

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Q. The conditions for flow beyond the boundary layer and its outer edge are

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Q. The thin layer where velocity changes continuously is called

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Q. The free stream undisturbed flow has a uniform velocity U INFINITY in the

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Q. The concept of hydrodynamic boundary layer was first suggested by

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Q. A flat plate 1 m by 1 m is placed in a wind tunnel. The velocity and temperature of free stream air are 80 m/s and 10 degree Celsius. The flow over the whole length of the plate is made turbulent by turbulizing grid placed upstream of the plate. Find the heat flow from the surface of the plate

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Q. A flat plate 1 m by 1 m is placed in a wind tunnel. The velocity and temperature of free stream air are 80 m/s and 10 degree Celsius. The flow over the whole length of the plate is made turbulent by turbulizing grid placed upstream of the plate. Find the thickness of hydrodynamic boundary layer at trailing edge of the plate

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Q. For a particular engine, the underside of the crankcase can be idealized as a flat plate measuring 80 cm by 20 cm. The engine runs at 80 km/hr and the crankcase is cooled by the air flowing past it at the same speed. Find loss of the heat from the crank case surface (t S = 25 degree Celsius). Assume the boundary layer to be turbulent

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Q. A flat plate was positioned at zero incidence in a uniform flow stream of air. Assuming boundary layer to be turbulent over the entire plate, workout the ratio of skin-friction forces on the front and rear half part of the plate

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Q. During test-run, air flows at 215 m/s velocity and 25 degree Celsius temperature past a smooth thin model airfoil which can be idealized as a flat plate. If the chord length of the airfoil is 15 cm, find drag per unit width. The relevant physical properties of air are

p = 1.82 kg/m³
v = 15.53 * 10¯⁶ m²/s

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Q. The average drag coefficient for turbulent boundary layer flow past a thin plate is given by

Cf = 0.455/ (log10 Rel)^2.58

Where R el is the Reynolds number based on plate length. A plate 50 cm wide and 5 m long is kept parallel to the flow of water with free stream velocity 3 m/s. Calculate the drag force on both sides of the plate. For water, kinematic viscosity = 0.01 stokes

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Q. Reynolds analogy is given by

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