Stream Lines

What is a stream line

These are lines that are everywhere tangent to the vector field in an instant in time

To find streamlines, we can use similar triangles…
Ex.
$\frac{dx}{u}=\frac{dy}{v}$ Where u and v are out x and y magnitudes respectively.

Facts:

• Fluids cannot cross a streamline (since it is tangent to the velocity)
• A bundle of stream lines is a stream tube
• The convergence or divergence of streamlines tell you where the flow is accelerating or decelerating (condense = fast)
• These give us an instantaneous look at our entire flow field
• Streamlines don’t let us follow a particle