Question

Interia force falls under which flow similarity?

(a) Geometric Similarity

(b) Kinematic Similarity

(c) Dynamic Similarity

(d) Dimensionless number

The question was asked in final exam.

My doubt stems from Infinitesimal Fluid Element topic in section Aerodynamics – Fundamental Principles and Equations of Aerodynamics

Answer 1

Correct option is (c) Dynamic Similarity

For explanation I would say: For a dynamic similarity, the model and prototype must be geometrically and kinematically similar along with the condition of total sum of forces acting at a point on model and prototype must be equal. Inertia force satisfies the condition and hence it falls under dynamic similarity.