Dear Sir, I am solving flow over a cylinder problem (time dependent)numerically. Could anyone help me how to plot streak lines? or Is there option in Tecplot to draw streak lines using u and v components like how we draw stream lines? Thank you

Tecplot Analyzer can do it. You can also add a module to your code to plot streak lines. Lemme try to give a brief idea of how u do it

1. Fix a point from which your numerical dye is getting injected.

2. Calculate the velocity at the point using Bilinear interpolation from Eulerian grid.

3. Update the position of the dye stream in time

dx/dt =u ; dy/dt =v

4. Repeat the calculation for all the dye streaks.

I am not sure if u r using fortran or c but what u need is a vector whose size u keep increasing with time to accomodate all the particles which keep getting injected into the flow.