Large Eddy Simulation (LES) is a mathematical model for turbulence used in computational fluid dynamics that is growing and is currently applied for many engineering applications. LES applies a low-pass filter on the Navier-Stokes equations to reduce the range of length scales to solve and thus the computational cost. The large scales of the flow field are resolved, allowing better fidelity than traditional approaches such as Reynolds-averaged Navier-Stokes (RANS), whereas the smallest scales are modeled rather than solved as direct numerical simulation (DNS) does, which makes the computational cost for practical engineering applications attainable using supercomputers.
ARCHES is a LES tool resulting of a ten year partnership with the Department of Energy's ASC program through the University of Utah's Center for Simulation of Accidental Fires and Explosions (C-SAFE). It is a massively parallel code that solves conserved quantities (mass, momentum, energy, scalar) spatially and temporally in a turbulent flow field, allowing for detailed and accurate simulations of fires and flames. The ARCHES code includes particle phase representation through the use of a moment method, i.e. the direct quadrature method of moments (DQMOM). DQMOM combined with LES allows ARHCES to perform highly accurate simulations of oxy-coal and coal gasification applications.
The ARCHES code is integrated into a C++ framework called Uintah, whose purpose is to provide large-scale parallelization tools for physics components. The code is constantly under development by a number of people and is maintained in an svn code repository. Distribution through the repository is freely available. Periodically, release distributions of the framework along with the ARCHES component can be found on the distribution website of Uintah. Questions regarding the ARCHES code may be directed at Dr. Jeremy Thornock.