Class on March 22 2019

Chris reviewed the location we are focusing on (the west passage) for the consulting work students were doing for the final project.

The area of study is a 20km passage (where warm surface water from north is above 23.5 C and cold bottom water from the south is much colder.

A factory to appear where Casey Farm currently exists, just north of the URI Bay Campus. The factory wants to release their waste chemical for a month in summer each year. Chemical stays inert under 23.5 degrees C (so we want to release only then — it sticks around for a month. We wan to keep it out of mixing with the colder bottom waters. The overall situation looks like this:



Students then took turns at the blackboard — writing out terms for the relevant advection-diffusion problem involved in the project scenario:



Students broke into teams to play out the advection-diffusion simulation while focusing on the relevant terms in the equation.



Students focused on recording data for the Eulerian (second row of parcels at head of flow) and LaGrangian (the blue highlighted parcel as it moved through the Eulerian area of study), and then they graphed the two on the blackboard (the LaGrangian plot on top of the Eulerian):



Chris then handed out homework set #6 and asked students to discuss the relationship of variables in teams:



Chris introduced the concept of upwind differencing which is critical for keeping advection models stable. To calculate dx1/dt, we always look towards the incoming flow to calculate. If the flow is coming at us from node i-1, we use i - (i-1) for the calculation, but if the flow is coming at us from node i+1, we use i - (i+i).

The computations will continue to become more cumbersome with the addition of more formula terms, but the light at end of the tunnel for the course is approaching such that only one more homework set (#7) will be necessary before the final analysis (homework set #7 will add chemical transport to the advection flow in homework #6)