$(2)$ Streamlines, streaklines, pathlines.... are all the same if the flow is

; but if not, then they

can be pretty different.

A factory discharges some smoke into the air. The

smoke is neutrally$-$buoyant, and simply goes with the

prevailing horizontal winds. The wind shifts

according to the following:

$,0t10$ hrs: $10mph$ towards east

$5mph20mph10mpht=10,20,30,40t=0,10,20,30hrst=0,30hrs$: $10mph$ towards east

For each $of$ the times $t=10,20,30,40hrs.,$ sketch and label the following for the smoke and wind field $(looking$

from above, not from the side$)$:

Streamlines for that particular time

Pathlines $of$ particles previously released $at$ times $t=0,10,20,30hrs(only$ particles already released$)$

Streakline showing all smoke particles released since $t=020hrs$: $20mph$ towards northwest

$,30hrs$: $10mph$ towards east

For each $of$ the times $t=10,20,30,40hrs.,$ sketch and label the following for the smoke and wind field $(looking$

from above, not from the side$)$:

Streamlines for that particular time

Pathlines $of$ particles previously released $at$ times $t=0,10,20,30hrs(only$ particles already released$)$

Streakline showing all smoke particles released since $t=010hrs$: $5mph$ towards southwest

$20hrs$: $20mph$ towards northwest

$,30hrs$: $10mph$ towards east

For each $of$ the times $t=10,20,30,40hrs.,$ sketch and label the following for the smoke and wind field $(looking$

from above, not from the side$)$:

Streamlines for that particular time

Pathlines $of$ particles previously released $at$ times $t=0,10,20,30hrs(only$ particles already released$)$

Streakline showing all smoke particles released since $t=0$