Cs382

This page documents the work of CS382 - Scientific Computing, Fall 2007

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Using the enVision Tabletop Groundwater Simulator

General Instructions

• Setup
• Teardown and cleaning
• Packing and travelling

Instructions for Demonstrations

• First one
• Second one
• etc.

Computational Groundwater Simulations

Fitz, Bryan and Mikio

Confined aquifier simulation

Parabolic contaminant flow model

Experiments

• Demonstrating porosity
  • model water flow unconfined aquifier
• Illustrating groundwater flow in a confined aquifer
  • We will use a cellular automata model where at the lowest level, a cell is either fresh water or contaminated. We see this problem split into two concepts - speed and direction.
    • Direction: The illustration to the right demonstrates our assumptions about how the water will move through the material. The simulation will calculate a new direction at each generation based on it's position relative to the known locations of water input and output.
    • Speed: Remains constant throughout generations for a given run. The "speed" value represents a combination of speed of water flow and material porosity, and in terms of the simulation is the possibility that a a neighboring cell in the flow direction becomes contaminated.
• Describing recharge, transition and discharge areas
  • modeling behavior of water recharge, discharge in wells, lake, etc

Computational Tools

• C
  • +Very fast
  • +Libraries are available
  • +Good distributed Libraries
  • -Potentially difficult to use
  • -no graphics libraries
• Netlogo
  • +Fancy Graphics
  • +Fun to use
  • +Available examples/code
  • -Slow
  • -Small problem size
  • -No Distributed processing

Peter and Mikio

Experiment

• Describing the model
  • Describing the various parts of the Groundwater Simulator by attaching tags: Key words -- wells, artesian wells, lake, underground storage tank, septic tank, springs, vegetative layer, river/ocean, recharge area, discharge area, aquifers, confining layer, clay layers
• Illustrating and Calculating Porasity of different types of earth materials
• Determining how it is easy for ground water to move in different earth materials.

Computetional Tool

• NetLogo for computatinal experiment

Brad and Nate

Our goal is an incremental approach towards illustrating groundwater contamination in a confined aquifer. The confined aquifer, viewed between wells 1 and 8, offers an environment within the groundwater simulator with the fewest variables. The first 4 experiments are an effort to illustrate the behavior and underlying science that must be understood and demonstrated in the final experiment.

Experiments

• Diffusion
  • Show diffusion without groundwater movement.
• Flow Rate
  • Show the leading edge of groundwater contamination as a indicator of flow rate (related to section 5 and 13 in manual)
• Contaminant Plume Length
  • Determine whether contaminant plume length is affected by flow rate for a given amount of dye
• Soil Density
  • Use displacement method and measurements of aquifer component to determine the density of the soil. We can use this value in silico.
• Illustrate laminar flow in a confined aquifer (Activity 7-1)
  • Show laminar flow between wells 1 and 8.

Computational Tools

• NetLogo
  • + Visualization built in
  • + Agent and cell based simulation structure built in
  • - Possible limitation on world size / agent count in RAM
  • - Possible run time slower than groundwater simulator at higher flow rates
  • - Not parallel
• Python and MYMPI
  • + Parallelizable
  • + Faster than NetLogo in serial code ?
  • + Visualization software exists
• TKInter - easy to install; seemingly easy to use
  • - Visualization software must be integrated
  • - MYMPI is untested
  • Need to compile stuff.

Plume Tracking - Bryan and Brad

Setup

• physical simulator setup approximately 16 inches away and perpendicular to the line of sight of a web enabled camera.
• A script was used to capture output of the output of the camera from the server at a rate of one every two seconds. A faster rate may be possible, but the current script did not have time to get the image and rename it within a 1 second interval.

Procedure

• set pump flow rate at maximum and allow water table to equalize
• start image capture script
• inject a full pipette bulb into well number 1
• remove pipette before allowing bulb to reinflate
• allow simulator to run for approximately 5 minutes or until the majority of the dye in the system has been discharged
• stop image capture script

We did three complete runs, each with a different dye colors. We used blue, purple and green because we thought they would give the most contrast for edge detection.

• run1.tgz (blue)
• run2.tgz (purple)
• run3.tgz (green)