Saturday, May 23, 2015

Streamlines and line of flow of fluid particles


I am very confused with this thing can someone clarify these problems given below-- 1 //Do or can the streamlines of a fluid particle show the position of the particle at a time( using the streamlines)?? 2// I know that streamlines cannot intersect because at a specific instant the particle reaching the intersection will have two different directions of motion (in the steady flow of particles), but can I say the same thing in turbulent flow for the LINE OF FLOW of the particles // why or why not?? 3//is it necessary that a streamLINE will be a perfect straight line(to a good approximation)?? If know why is it called a line then??



Answer




  • On a steady flow, streamlines correspond to the trajectory of "fluids particles" or parcels. (Not to be confused with the one of the real "particles" that are the molecules.)


  • But if it's not a steady flow, it's wrong. You might even see appearant source and sink in the lines that do not exist as a flow.

  • Steady flow streamlines cannot cross because of basic continuity and conservation laws: otherwise a particle should teleport itself on the other side of the obstacle that is the crossing flow ;-)

  • A streamline is a curve, not especially a straight line.

  • More on wikipedia.


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