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Streamlines can also be computed, by picking the Streamline option in the Add drop down menu near the Results category. Select the faces of the Ahmed body as the Seed location. Then, change Distribution to Based on mesh and At every Nth item to 10.
Press Evaluate. If desired, change the Wire thickness in the Appearance section to alter how big the streamlines are. Press the Play button in the model window to see how these streamlines develop over time.