A. In case of boundaries experiencing form drag
B. At points of abrupt changes in the flow directions
C. In laminar flow
D. None of these
Related Mcqs:
- Which of the following must be followed by the flow of a fluid (real or ideal)? (I) Newton’s law of viscosity. (II) Newton’s second law of motion. (III) The continuity equation. (IV) Velocity of boundary layer must be zero relative to boundary. (V) Fluid cannot penetrate a boundary?
A. I, II, III
B. II, III, V
C. I, II, V
D. II, IV, V - Bernoulli’s equation for fluid flow is derived following certain assumptions. Out of the assumptions listed below, which set of assumptions is used in derivation of Bernoulli’s equation? A. Fluid flow is frictionless & irrotational. B. Fluid flow is steady. C. Fluid flow is uniform & turbulent. D. Fluid is compressible. E. Fluid is incompressible ?
A. A, C, D
B. B, D, E
C. A, B, E
D. A, D, E - In the laminar boundary layer flow over a flat plate, the ratio (δ/x) varies as: (where, ‘δ’ is the boundary layer thickness and ‘x’ is the distance from the leading edge in the direction of flow)?
A. Re
B. √Re
C. 1/Re
D. Re-1/2 - The effect of solid boundary on the fluid flow is confined to the boundary layer, except for fluids ?
A. Having high viscosities
B. Moving at low velocities
C. Both A. & B.
D. Neither A. nor B. - The ratio of hydrodynamic boundary layer to thermal boundary layer thickness in case of liquid metals is__________________?
A. < 1
B. 1
C. > 1
D. 2 - Boundary layer separation is characterised by one of the conditions given below, where ‘Re’ is the Reynolds number for the flow. Select the appropriate conditions ?
A. Re <> 1, accelerating flow
C. Re << 1, decelerating flow
D. Re >>1, decelerating flow - The boundary layer is that part of a moving fluid, in which the fluid velocity is_________________?
A. Affected by the fluid flow pressure
B. Constant
C. Affected by the presence of a solid boundary
D. All A., B. and C. - Existence of boundary layer in fluid flow is because of the_________________?
A. Surface tension
B. Fluid density
C. Fluid viscosity
D. Gravity forces - In which type of fluid flow, the velocity of flow of fluid changes from point to point in the fluid at any instant ?
A. Rotational
B. Unsteady
C. Turbulent
D. Non-uniform - Boundary layer separation is caused by the_________________?
A. Reduction of pressure to vapour pressure
B. Boundary layer thickness reducing to zero
C. Adverse pressure gradient
D. Reduction of pressure gradient to zero