Question

Which among the following have the same forces acting on them?

(a) Geometric similarity

(b) Kinematic similarity

(c) Dynamic similarity

(d) Conditional similarity

The question was asked at a job interview.

This key question is from Similitude topic in chapter Dimensional and Model Analysis of Fluid Mechanics

Answer 1

The correct choice is (c) Dynamic similarity

To elaborate: Dynamic similarities have the same forces acting on them. That means, the ratios of all the forces acting on the fluid particles are constant. Also, the ratio of the forces acting on the boundary surfaces are also a constant.