RiverFLO-2D Translation

RiverFLO-2D Translation Routine

A conversion routine has been written to convert ASCII River-FLO2D datasets into EnSight Case Gold format. This solver (http://www.flo-2d.com/products/riverflo-2d/) generates both a “.FED” file, and a series of “.EXP” files. The .fed file contains the geometric mesh. There is one .EXP file for each timestep, with a fixed specification of U & V velocities, water surface elevation, depth, and elevation as a per node variable. The time value is actually written as part of the .EXP filename, so the python routine parses that out and converts it into a time that EnSight can handle. Now, the time unit for the velocity is in seconds, so naturally you would want to specify time in seconds for EnSight. However, the time range for simulations is on the order of days, so reporting it as seconds is awkward. The python routine has a toggle to specify how the time is actually represented in the .case file so that graphs and integrations with time make more sense. By converting to anything other than seconds does mess up the pathline operation, but as that is not used for these models, it is okay.

              The translation routine takes each of the incoming file and convert to EnSight Case Gold files. This ensures that the translation only occurs once. Each subsequent load of the model, the user can directly load in the .case file. In addition, items like changing timestep now happen very quickly, and provide the optimal operation of the model results in EnSight. To keep directories as neat and tidy as possible, I create an “ensight_files” directory, and place all of the .geo and variable files there.

              The inputs from the user are to specify the ".FED" file, one of the ".EXP" files, and specification of the Time option. The 'fed" file is used to generate the grid information, while the .EXP file is used to determine which directory the EXP files are, and then the python routine grabs all *.EXP files in that location to convert to variable information (per node vars). The Time option is used to determine how to best present the "Analysis_Time" in EnSight. Hours are much more useful and meaningful than other units of time, and is therefore the default.

              The datasets are all 2D elements. They typically lie in the XY plane, with the elevation given as the Z coordinate. Timesteps are typically a few hundred, and dataset sizes are typically 200k to 500k. All of the variables are nodal, and exist for the 2D parts only. The datasets are originally prescribed in “global” coordinates. There are too many significant digits for EnSight to handle this properly, and thus this routine converts the model into “local” coordinates. The offset between local and global coordinates is referenced in the Constant variables “Xref” and “Yref”.

Users will take advantage of the isosurface and isovolume tools in EnSight to restrict and create new parts. Calculator quantities including the EleSize * Water Depth will result in volume quantities like how much water volume is in each element. Querying variables over time, or creating clips and graphs on the clips over time are of significant help in analyzing the flow rates, distributions and temporal information. Use of the TempMean and TempMinMax functions allow the user to see an envelope of flood depth as a great indication of maximum depth reached over time.

              To facilitate the time reporting, there are constants per timestep written in the form of days, hours, minutes, seconds so that we can create the appropriate labels for time. As part of the River & Flood Simulation toolset, there is a "Time Annotation" tool, which is described here (Time Annotation for River/Flood Sim).

Kevin Colburn. May 2012. Tool Version 2.0