How can I get streamlines?

Hello everyone, I need your help to create streamlines. I have a matrix of 3276 rows and 4 columns, the first column represents the 'x' coordinates of the row, the second column represents the 'y' coordinates of the rows, the third column represents the 'x' component of the velocity vector (at that point) and the fourth column represents the 'y' components of the velocity vector (at that point). In particular, this matrix represents the instantaneous velocity field of a air flow exiting from a nozzle. Here below is an example of my matrix:

 ------ -------- ------- -------
 22.23 |   0    | -0.24 | 1.28  |
 22.21 |   0    | -0.13 | 1.30  |
  ...  |  ...   |  ...  |  ...  |
-23.15 |   0    |  0.08 | 1.27  |
------- -------- ------- -------
 22.23 |   0.67 | -0.22 | 1.26  |
 22.21 |   0.67 | -0.24 | 1.33  |
  ...  |  ...   |  ...  |  ...  |
-23.15 |   0.67 |  0.12 | 1.59  |
------- -------- ------- -------

...    ...      ...     ...

 ------ -------- ------- -------
 22.23 |  35.41 | 15.57 | 2.07  |
 22.21 |  35.41 | 16.94 | 2.01  |
  ...  |  ...   |  ...  |  ...  |
-23.15 |  35.41 |-20.14 | 1.04  |
------- -------- ------- -------

What I can not get are the streamlines of flow, which are directed from the bottom upwards, quite straight in the center of the reference system and then fraying upwards. What should I get is this:

             y axis
    ^
    \ \ \\|// / /
     \ \ \|/ / /
      \ \ | / /
       \ \|/ /  
        \  | /
        |  | |
        | | |  
        | | |
        | | |  
        | | |
           ----------> x axis

How can I get the streamlines? Thanks for your help, soon. Mario