Question

Which of the following is correct?

(a) A streamline can intersect itself and two streamlines can cross

(b) A streamline cannot intersect itself but two streamlines can cross

(c) A streamline can intersect itself but two streamlines cannot cross

(d) A streamline cannot intersect itself and two streamlines cannot cross

I had been asked this question at a job interview.

The question is from Types of Flow Lines in division Kinematics of Flow and Ideal Flow of Fluid Mechanics

Answer 1

Right choice is (d) A streamline cannot intersect itself and two streamlines cannot cross

To explain: A streamline is defined as an imaginary line within the flow such that the tangent at any point on it indicates the velocity at that point. At a point, there can only be one direction of velocity. Hence, neither can a streamline intersect itself nor can two streamlines cross each other.