Explain streamline and streamline flow.

(N/A) The path taken by a fluid particle in a flowing fluid is called its line of flow.
In a moving fluid,the velocity and direction of particles generally change over time. Therefore,particles passing through a single point may not follow the same path.
However,in steady flow,the velocity of any particle passing through a specific point remains constant over time.
Suppose the velocity of a particle passing through point $P$ is $\overrightarrow{V}_{P}$,and the velocities of particles passing through points $Q, R$,and $S$ are $\overrightarrow{V}_{Q}, \overrightarrow{V}_{R}$,and $\overrightarrow{V}_{S}$ respectively.
In steady flow,the path of a particle passing through point $P$ is shown in the figure. This steady path is known as a streamline.
In steady flow,the line of flow and the streamline coincide.
Streamline: $A$ streamline is a curve such that the tangent at any point on it gives the direction of the velocity of the fluid particle passing through that point.
Streamline flow: $A$ flow in which streamlines can be defined is called streamline flow.
In unsteady flow,a line of flow can be defined for a specific particle,but a streamline cannot be defined because the velocity at a point changes with time.