Question

The absence of vorticity means the flow is ________

(a) steady

(b) unsteady

(c) rotational

(d) irrotational

The question was posed to me by my school principal while I was bunking the class.

My query is from Angular Velocity, Vorticity, Strain topic in division Aerodynamics – Fundamental Principles and Equations of Aerodynamics

Answer 1

The correct answer is (d) irrotational

Easiest explanation: The absence of vorticity means the flow is irrotational flow, which simplifies the flow analysis. This is greatly used in case of inviscid flows. The flow analysis becomes easy for irrotational flow since there is no rotational motion of the fluid element.