Stream lines and streak lines

this topic is from fluid mechanics and is about stream lines and streak lines along with diagrams....

1. A  streamline  is a path traced out by a massless particle as it moves with the flow . OR A streamline is one that is drawn tangential to the velocity vector at every point in the flow at a given instant and forms a powerful tool in understanding flows.

2. Stream lines

3. Explanation A moving body causes the air to flow around it in definite patterns, the components of which are called streamlines . Smooth, regular airflow patterns around an object are called laminar flow  they denote a minimum of disturbance of the air by the object’s motion through it.  Turbulent flow occurs when air is disturbed and separates from the surface of the moving body, with the consequent formation of a zone of swirling eddies in the body’s wake .

4. Streak line The locus of all the points that have gone through a given point in a flow is called streak line. It concentrates on fluid particles that have gone through a fixed station or point. At some instant of time the position of all these particles are marked and a line is drawn through them. Such a line is called a streak line  

5. Streak line