Los Alamos National Laboratory
Lab Home  |  Phone
 
 
LANL: >> EES Home
EES Resources


Walkabout

Walkabout Version 1 (LA-CC-11-033) performs random walk particle tracking simulations of solute transport based on groundwater flow solutions that use fully unstructured control volume grids. Walkabout 1.0 is designed to work within the FEHM (Zyvoloski, 2007) code system, and accepts groundwater flow solutions from FEHM and computational mesh descriptions from LaGrit (Los Alamos Grid Toolbox,
A typical workflow for Walkabout within the FEHM system would use LaGrit to generate unstructured grids. FEHM then provides a discretized representation of the steady-state flow field to Walkabout. Given this discrete solution, Walkabout then reconstructs a groundwater flow field, and performs the random walk particle tracking calculation. Output is provided in a form compatible with the PLUMECALC software. PLUMECALC may be used to efficiently post-process the particle tracking results from Walkabout to add effects of retention/retardation and arbitrary source histories. An option exists to also record particle positions versus time, thus allowing other post-processing codes or visualization systems to be used.


Walkabout Features and Limitations


• Walkabout works on fully unstructured tetrahedral meshes in three spatial dimensions. Two-dimensional meshes and meshes other than tetrahedral meshes are not supported in Version 1.0.
• A control-volume solution for steady groundwater flow is required. Finite-element solutions are not supported. Transient flow is not supported in Version 1.0.
• All particles are launched at time zero. The PlumeCalc (plumecalc.lanl.gov) software maybe used to postprocess the resulting particle tracks to obtain concentration for an arbitrary source history.
• Particles are moved through the system without decay or retardation. The PlumeCalc (plumecalc.lanl.gov) system may be used to postprocess the particle tracks to obtain concentration with decay and matrix diffusion or other retardation/retention processes.
• The Burnett and Frind (1987) model for dispersion coefficient is presumed.
• Full heterogeneity in porosity, liquid density, liquid saturation index, and dispersivity is supported.


Walkabout Documentation

This User Manual summarizes the technical basis for the Walkabout code, describes the input and output formats, documents verification testing, and provides example test cases that exercise the full range of capabilities.

  "User Manual for Walkabout Version 1.0 (PDF) "


Walkabout Distribution


Walkabout V1 is now open source.
For latest versions and documentation go to https://github.com/lanl/walkabout


• Version 1.2 (November 2011)

"Walkabout Release Notice (PDF)"

Includes a slightly modified algorithm that eliminated a problem with numerical roundoff that caused the code to enter an infinite loop on rare occasions when searching for the computational cell containing the current particle.

Includes a new time step control algorithm that eliminates spurious steps in situations of a very large contrast in velocity.



Copyright 2016. Los Alamos National Security, LLC. This software was produced under U.S. Government contract DE-AC52-06NA25396 for 
Los Alamos National Laboratory (LANL), which is operated by Los Alamos National Security, LLC for the U.S. Department of Energy. 
The U.S. Government has rights to use, reproduce, and distribute this software.  NEITHER THE GOVERNMENT NOR LOS ALAMOS NATIONAL SECURITY, 
LLC MAKES ANY WARRANTY, EXPRESS OR IMPLIED, OR ASSUMES ANY LIABILITY FOR THE USE OF THIS SOFTWARE.  If software is modified to produce 
derivative works, such modified software should be clearly marked, so as not to confuse it with the version available from LANL.

Additionally, redistribution and use in source and binary forms, with or without modification, are permitted provided that the 
following conditions are met:
    - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 
    - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer 
      in the documentation and/or other materials provided with the distribution. 
    - Neither the name of Los Alamos National Security, LLC, Los Alamos National Laboratory, LANL, the U.S. Government, nor the names 
      of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. 

THIS SOFTWARE IS PROVIDED BY LOS ALAMOS NATIONAL SECURITY, LLC AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, 
BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 
LOS ALAMOS NATIONAL SECURITY, LLC OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.




Operated by Los Alamos National Security, LLC for the U.S. Department of Energy's NNSA

Inside | © Copyright 2010-11 Los Alamos National Security, LLC All rights reserved | Disclaimer/Privacy | Web Contact