Assuming that you're using Fluent, there two ways of doing it:
1. From Fluent:
File > Export > Solution Data; File Type: ASCII, and select the appropriate contour plane with the specific contour variable of interest along with the plane coordinate axes. This will export the data into a csv file which can be imported in MATLAB.
2. From CFD-Post:
File > Export > Export...; Type: Generic, and select the required surface with the variable of interest. This will create a csv file which can be imported into MATLAB. If your mesh is too fine and if you don't need all the data, you can "Insert > Point Cloud" at the selected surface which the required point density and you can export this Point Cloud the same way as mentioned earlier.
You are navigating away from the AIS Discovery experience