3.3 Path line

Fig 7.3 Path Lines

• Path line refers to a path followed by a fluid particle over a period of time and show direction of velocity

•  Two path lines can intersect each other as or a single path line can form a loop as different particles or even same particle can arrive at the same point at different instants of time.

• While stream lines shows an imaginary curve in a flow field for a fixed instant of time, tangent to which gives the instantaneous velocity at that point.

• Two stream lines can never intersect each other, as the instantaneous velocity vector at any given point is unique.

Next flow rate and mean velocity http://fluidbloggroup3.blogspot.com/2014/05/fluid-34-35.html