# Streamline Plot from velocity discrete values

I solved Navier Stokes equation in C for lid driven cavity flow and extracted converged values of u velocity and v velocities in .dat file.

Is there a way to generate streamlines from these discrete values of u and v in Mathematica?

u.dat & v.dat

I have attached link for u.dat and v.dat files, but even if someone can guide me with his own data set, I will be thankful.

• And what is the u and v? Have you looked in the ListStreamPlot documentation? – m0nhawk Apr 12 '15 at 6:45
• @m0nhawk : Hi, I looked in the documentation of ListStreamPlot but was not able to figure out my problem. u is the x direction velocity and v is the y component of velocity. I solved NS equations using FDM methods on a grid size of 401X401, so basically u and v represents velocity values at these grid points. u and v are 401X401 matrix – user11948 Apr 12 '15 at 17:05

The main thing with the ListStreamPlot is that it needs a data in a form of list of {{x, y}, {vx, vy}} pairs.

vx = Import["Re1000_c100_u.dat", "CSV"];
vy = Import["Re1000_c100_v.dat", "CSV"];

x = Table[j, {i, 0, Length[vx] - 1}, {j, 0, Length[vy] - 1}];
y = Table[i, {i, 0, Length[vx] - 1}, {j, 0, Length[vy] - 1}];

ListStreamPlot@MapThread[{{#1, #2}, {#3, #4}} &, {x, y, vx, vy}, 2]


I'm not sure if the MapThread is the most efficient way to create a necessary list.

• Transpose[{{x, y}, {vx, vy}}, {3, 4, 1, 2}] is another way to arrange the data for ListStreamPlot. (+1) – Michael E2 Apr 12 '15 at 17:48