Fluid Mechanics and Hydraulic Machinery Miscellaneous

Fluid Mechanics and Hydraulic Machinery

1. Streamlines, path lines and streak lines are virtually identical for

1. NA

Correct Option: C

NA

1. For a fluid element in a two dimensional flow field (x-y plane), if it will undergo

1. NA

Correct Option: C

NA

1. Within a boundary layer for a steady incompressible flow, the Bernoulli equation

1. Bernoulli equation does not hold because the flow is frictional.

Correct Option: D

Bernoulli equation does not hold because the flow is frictional.

1. A flat plate of width L = 1 m is pushed down with a velocity U = 0.01 m/s towards a wall resulting in the drainage of the fluid between the plate and the wall as shown in the figure. Assume two- dimensional incompressible flow and that the plate remains parallel to the wall. The average velocity, uavg of the fluid (in m/s) draining out at the instant shown in the figure is _____ (correct to three decimal places).

1. By mass conservation:- 2(s × uavg × db) = (s. u × Lb)
⇒  2 × vavg × 0.1 = 0.01 × 1
uavg = 0.05 m/s

Correct Option: C

By mass conservation:- 2(s × uavg × db) = (s. u × Lb)
⇒  2 × vavg × 0.1 = 0.01 × 1
uavg = 0.05 m/s

1. A mercury manometer is attached to a section of the pipe shown in the figure. Mercury levels are indicated when there is no water flowing through the pipe. When water starts flowing through the pipe continuously at constant rate in the direction of the arrow, the level of mercury at B.

1. When flow starts, pressure at B will be lower than pressure at A, therefore level of mercury at B rises.

Correct Option: A

When flow starts, pressure at B will be lower than pressure at A, therefore level of mercury at B rises.