• Streamline • Pathline • Streakline • Timeline

Fluid Lines
• Streamline
– everywhere tangent to instantaneous velocity vector
• Pathline
– actual path traversed by a fluid packet
• Streakline
– locus of fluid packets that have all previously passed
through a specific point in the flow
• Timeline
– set of fluid packets that form a line at some instant in
time
JMS010402-1
AE3051
Hele-Shaw Flow
•Creeping flow: water with dye lines (streaklines)
JMS010402-2
AE3051
Particle Trajectories in Periodic Water Waves
•Wave moving from left hitting (partially) reflected wave from right (pathlines)
Reflection
0%
50%
100%
JMS010402-3
AE3051
Blausius Boundary Layer Profile
Wire
• Fine tellerurium wire +
few ms electrical
impulse produces
chemical reaction in
water
• Cloud of product drifts
with tangential velocity
• Time line,
Visualize displacement
(velocity)
Wall
JMS010402-4
AE3051
Planar Visualization of 2-D Mixing Layer
• 2-D flow in channel, higher velocity fluid on top
• Low speed fluid contains dye that fluoresces when hit by
vertical laser sheet (laser sheet visualization)
JMS010402-5
AE3051
Airfoil Wake
•6:1 elliptical cylinder at zero angle of attack (Rechord=4000)
•Drop of TiCl4 (liquid) on surface forms white smoke as it
interacts with water vapor in the air
•Laminar boundary layer separates, forms wake, sheds
vortices
JMS010402-6
AE3051
Delta Wing Vortices
•Thin wing, 15° semi-vertex at 20° angle of attack (Re=20,000)
•Lines of colored fluid injected from wing
JMS010402-7
AE3051
Tanker Wake
• Grounded tanker (Argo Merchant, 1976)
• Oil spilling with current at 45° to ship
JMS010402-8
AE3051
Turbulent Distortion of Material Lines
• Fine platinum wire in water tunnel behind turbulence grid
• Periodic pulsing produces double lines of H2 bubbles
JMS010402-9
AE3051
Smoke Tunnel
JMS010402-10
AE3051