Chris put the students into teams of two and asked them to locate a parcel of water in the classroom based on a dimensionless L of 2 in both the east-west and north-south directions. The teams then did a series of computations for their parcel in the context of the whole body of simulated water.

The situations built in complexity until a situation suggested a temporary paradox where L₁ became 10 meters in one dimension and T became the other dimension of interest. Students had to find the value of parcels of water as time marched forward from 0 to 1:



The paradox could be resolved with the introdution of advection.

Chris then presented an advection problem in an alternative, more typical, way of describing it:



Students then calculated an estimated advection term at different locations between Providence and Boston along the X₂ axis:

X₂ (km)             U₂ (km/h)

0        |       80
10       |       80
20       |       80
30       |       40
40       |       10
50       |       20
60       |       30
70       |       40
80       |       50
90       |       50
100      |       50

The surface flow could be used to estimate time for moving from Providence to Boston:

The first 30km would be covered in 22.5 minutes (60 min/h * 30/80)
The next 10km would be covered in 15 minutes (60 min/h * 10/40)
The next 10km would be covered in 60 minutes (60 min/h * 10/10)
The next 10km would be covered in 30 minutes (60 min/h * 10/20)
The next 10km would be covered in 20 minutes (60 min/h * 10/30)
The next 10km would be covered in 15 minutes (60 min/h * 10/40)
The last 20km would be covered in 24 minutes (60 min/h * 20/50)

so that the total estimated time in transit would be 186.5 minutes (3 hours and 6.5 minutes).

Students were then asked to work on homework set #5:



for the weekend and Spring Break. Homework set #6 would add advection mechanics to the 2-D molecular diffusion base coded in homework set #5.