This module was developed by ATA Engineering as an add-on to the Loci/CHEM computational fluid dynamics (CFD) solver. The module is useful to reduce reflections emanating from boundary conditions during unsteady simulations. This can be critical in analyses where accurately resolving pressure fluctuations is important. Such analyses include large eddy simulations, aeroacoustic simulations, and combustion instability simulations.
This module depends on both Loci and CHEM being installed. Loci is an open source framework developed at Mississippi State University (MSU) by Dr. Ed Luke. The framework provides a rule-based programming model and can take advantage of massively parallel high performance computing systems. CHEM is a full featured open source CFD code with finite-rate chemistry built on the Loci framework. CHEM is export controlled under the International Traffic In Arms Regulations (ITAR). Both Loci and CHEM can be obtained from the SimSys Software Forum hosted by MSU.
First Loci and CHEM should be installed. The LOCI_BASE environment variable should be set to point to the Loci installation directory. The CHEM_BASE environment variable should be set to point to the CHEM installation directory. The installation process follows the standard make, make install procedure.
make
make installFirst the module must be loaded at the top of the vars file. The user can then specify nonreflecting inflow and/or outflow boundary conditions. The nonreflecting versions of inflow and outflow accept the same input as their reflecting counterparts, but can also take additional input regarding the simulation domain length scale and a boundary condition constant. The moudle should only be used for time accurate simulations.
loadModule: nonreflecting
boundary_conditions:<BC_1=inflowNRBC(p=101300 Pa, T=300K, M=0.5, sigma=0.25, length=0.1 m),
BC_2=outflowNRBC(p=101300 Pa, sigma=0.25, length=0.1 m)>