Pick out the wrong statement about a streamline.
A. It is always parallel to the main direction of the fluid flow
B. It is a line across which there is no flow and it is equivalent to a rigid boundary
C. Streamlines intersect at isolated point of zero velocity and infintie velocity
D. The fluid lying between any two streamlines can be considered to be in isolation and the streamline spacing varies inversely as the velocity
Answer: Option C
Solution (By Examveda Team)
Streamlines are lines that are tangent to the velocity vector of the flow at every point.Option A is correct – Streamlines are always parallel to the direction of fluid flow.
Option B is correct – There is no flow across a streamline, making it similar to a rigid boundary in fluid analysis.
Option C is incorrect – Streamlines never intersect. If they did, it would imply two different velocity directions at the same point, which is physically impossible.
Option D is correct – The fluid between two streamlines behaves like an isolated streamtube, and the spacing between streamlines varies inversely with the velocity (closer spacing indicates higher velocity).
Correct Answer: Option C: Streamlines intersect at isolated point of zero velocity and infinite velocity
This Question Belongs to Chemical Engineering >> Fluid Mechanics
The wrong statement is:
C. Streamlines intersect at isolated point of zero velocity and infinite velocity
🔍 Explanation:
Let’s evaluate each option one by one:
A. It is always parallel to the main direction of the fluid flow
✔ Correct
A streamline is tangent to the velocity vector of the fluid at every point.
So, the fluid flows along the streamline, and it is always aligned with the local flow direction.
B. It is a line across which there is no flow and it is equivalent to a rigid boundary
✔ Correct
In ideal flow (especially inviscid or irrotational flow), no fluid crosses a streamline.
Hence, it can be treated like a slip surface or boundary.
C. Streamlines intersect at isolated point of zero velocity and infinite velocity
❌ Wrong Statement
Streamlines can never intersect. If they did, a single point would have two different velocity directions, which is physically impossible.
At stagnation points (where velocity is zero), streamlines approach but do not intersect.
Also, infinite velocity is non-physical in real fluid flow.
D. The fluid lying between any two streamlines can be considered to be in isolation and the streamline spacing varies inversely as the velocity
✔ Correct
This is the concept of a streamtube.
Due to continuity, if streamlines are closer together, velocity is higher, and vice versa.
❌ Final Answer (Wrong Statement):
C. Streamlines intersect at isolated point of zero velocity and infinite velocity