# GATE Questions & Answers of Dimensional analysis and hydraulic similitude

## What is the Weightage of Dimensional analysis and hydraulic similitude in GATE Exam?

Total 6 Questions have been asked from Dimensional analysis and hydraulic similitude topic of Hydraulics subject in previous GATE papers. Average marks 1.67.

In a laboratory, a flow experiment is performed over a hydraulic structure. The measured values of discharge and velocity are 0.05 m3/s and 0.25 m/s, respectively. If the full scale structure (30 times bigger) is subjected to a discharge of 270 m3/s, then the time scale (model to full scale) value (up to two decimal places) is ______

The drag force, FD on sphere kept in a uniform flow field depends on the diameter of the sphere, D; flow velocity, V; fluid density, $\rho$; and dynamic viscosity,$\mu$. Which of the following options represents the non-dimensional parameters which could be used to analyze this problem ?

The relationship between the length scale ratio (Lr) and the velocity scale ratio (Vr) in hydraulic models, in which Froude dynamic similarity is maintained, is:

Group-I contains dimensionless parameters and Group- II contains the ratios.

 Group-I Group -II P. Mach Number 1. Ratio of inertial force and gravitational force Q. Reynolds Number 2. Ratio of fluid velocity and velocity of sound R. Weber Number 3. Ratio of inertial force and viscous force S. Froude Number 4. Ratio of inertial force and surface tension force

The correct match of dimensionless parameters in Group- I with ratios in Group-II is: