List of top Fluid Mechanics and Thermal Sciences Questions on Fluid Mechanics asked in GATE PI

A fluid with dynamic viscosity \( \mu = 1 \, \text{Pa.s} \) is flowing through a circular pipe with diameter 1 cm. If the flow rate (discharge) in the pipe is 0.2 liters/s, the maximum velocity in m/s of the fluid in the pipe is (assume fully developed flow and take fluid density \( \rho = 1000 \, \text{kg/m}^3 \)) _________.

A circular tank of 4 m diameter is filled up to a height of 3 m. Assuming almost steady flow and neglecting losses, the time taken in seconds to empty the tank through a 5 cm diameter hole located at the center of the tank bottom (take acceleration due to gravity \( g = 9.81 \, \text{m/s}^2 \)) is [round off to the nearest integer].

The dimensionless number defined by the ratio of inertial force to viscous force is called

A small capillary tube of 3 mm inner diameter is inserted into a fluid having density 900 kg/m\(^3\), surface tension 0.1 N/m, and contact angle 30°. The rise in the height of fluid in the capillary tube due to surface tension is