On Fan Boundary and Initial Conditions in General
- oundary conditions are extremely important. See also Chapter (), where the boundary conditions are described.
- The computational model can be either compressible, or incompressible.
- The typical criteria for using compressible model is the density is varying by , or the Mach number is larger than .
- Within this fan tutorial the fluid flow model is compressible.
- At the inlet the atmospheric total pressure and total temperature are prescribed
- At the outlet outletVent boundary condition is prescribed
- At the rigid walls velocity is zero.
- For rotational components the Multiple Reference Frame (MRF) is used.
- For steady-state computations the initial conditions have no influence to the results.
- For steady-state computations the initial conditions just help to make the case run.
The quantities to be set are following:
- static pressure p
- static temperature T
- velocity vector U
- turbulent kinetic energy k
- specific turbulence dissipation omega
The initial and boundary conditions for all variables are set in files located in directories named by numbers. Typically directory 0 is recommended to start a simulation from. Initial conditions are set in parameter internalField putting the values into the cell centers. At boundaries, initial conditions are set individually by parameter value.
# cp -r 0.org/* 0