Cs382/Flow Rate Experiment
From Earlham Cluster Department
This is a detailed description of one experiment listed on the CS382 course page
The goal of this experiment is to observe the flow rate of a dye plume in the groundwater simulator and note the plume's properties as it the dye travels through sand or gravel. The data gathered here will be used to verify a computer simulation of groundwater contamination.
- enVision sand and gravel groundwater simulator
- water soluble dye
- kitchen timer or some other time measurement device
- Fill the groundwater simulator with fresh water This yields the greatest contrast between the dye plume and surrounding clean water.
- Open the ocean valve and close the river valve.
- Make the pump's output approximately halfway between its maximum and minimum.
- Allow time for the water table to stabilize.
- Fill the pipette at least halfway full with dye.
- Insert the pipette completely into well number 1 (confined artesian aquifer)
- Inject enough dye into the well to create a quarter sized plume.
- Keep the pipette's bulb depressed until after it is removed from the well to avoid creating a vacuum and sucking dye from the plume back into the well. A little of this may occur as the water level in the well rises to fill the space formerly occupied by the pipette's barrel.
- Measure the distance from the bottom of the well and the plume's leftmost edge and start the timer in the horizontal plane.
- Continue to measure the plume's leading edge at regular intervals until the plume has reached well number 8.
- Repeat this experiment using well number 2.
- Graph your results.
- Determine the velocity of the plume's leading edge.
- <math>d(t)</math> = distance between source well and leading edge of plume at time interval <math>t</math>
- velocity = <math>(d(t2)-d(t1))/(t2-t1)</math>
- Does the plume's velocity change over time?
- Is there a direct correlation between the flow rate and the plume velocity?
- How did your two runs differ? What might account for this?
- Why might the flow rate differ in different parts of the simulator?
Considerations for a Computer Based Simulation
- If the flow rate is not constant within runs, how might we account for this in the simulation?