LUCI - Stochastic Hydrodynamics

One of the more interesting applications of visualization and simulation is in figuring out where water will flow.  Water is the key to most problems - too much and erosion dominates, too little and there are environmental consequences.  Hydrology and keeping track of water is one of the least understood problems.  The deficiency is not for lack of trying, but in the limitations of simulations and the lack of concrete real information on factors like topography, soil friability, soil character, etc...

We are taking the approach that is suggested by DSM and using the topography as a starting point.  The simulations shown below are simple demonstrations of how topography directs flow over a natural surface.  Even the smallest bump or feature has an effect.  One of the main tenets of DSM is that crops will grow best along the sides of terrain features.  This is an idea that is supported by image analysis which suggests that organic matter and nutrients are taken from the top of local features and driven down the sides and into channels.  This description is true whether the features are meters taller than the surround area, or millimeters taller than the surround area.  This erosion process is the same that creates things like the Niagara Gorge over tens of thousands of years, but it is hard for people to imagine erosion being a factor in seconds or minutes and over scales of only a few meters.

This simulation was the first that we developed to show topography reorganizing flow.  'Raindrops' are introduced in a very regular pattern and are quickly concentrated and redirected by the surface topography.

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The following simulation shows the correspondence between the flow generated via the topolgy and a streamflow solution generated by SOLIM over the same terrain.  The streamflow solution makes and excellent map, but the moving spheres give a sense to the implied motion in the map.

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Because DSM research shows that plants grow best on the sides of terrain features the knowledge of how water flows over the surface is critical - and this knowledge is not supplied by typical streamflow solution maps.  The reason its important is because of the motion of the nutirents and the deposition of organic matter an nuturients in densities that are acceptable to plants.  At the top of features there is divergence of nutrients (and consequently low densities) and at the bottom of features there is concentration (and consequently high densities), what happens in the middle, on the slopes of features, where plants grow best, is clearly where the interst should be.  These are also the areas that are most active in erosion.  Consequently, visualizations of the motion of particles over a topography are critical to understanding the growth enhancements suggested by DSM and observed in the field.