Incompressible limitIn this section we present the numerical results of AeroFoam
solver for a 2D aerodynamic test problem, such as the
inviscid unsteady flow around a fixed cylinder in the incompressible regime, since characteristic splitting methods suffer a little when the freestream Mach Moo number is very low.
Problem definition Domain:
 Internal circular subdomain with radius R = 0.5 m
 External circular subdomain with radius Roo = 25 m >> R
 Material:
 Polytropic Ideal Gas (PIG)
 Specific heat ratio gamma = 1.4
 Gas thermodynamic constant R = 287.05 J/kgK
 Initial conditions:
 Thermodynamic pressure Poo = 101325 Pa
 Temperature Too = 288.15 K
 Mach number Moo = 0.1
 Boundary conditions:
 Slip boundary conditions on internal subdomain
 Riemann boundary conditions on external subdomain
Figure: Problem definition.
Space and time discretization Space discretization:
 Mesh created with Gmsh
 # of triangular cells Nv = 15247
 # of nodes Nn = 15484
 Time discretization:
 Total simulation time endTime = 0.2 s
 Timestep deltaT = 1e5 s
 Maximum Courant number maxCo = 1.5
Figure: Computational grid. Numerical results Comparison with exact solution of potential theory
 Single iteration CPUtime = 0.09 s on AMD64 3500+ desktop PC with AMD Athlon 64 2.2 GHz CPU, 1 Gbyte RAM, 512 Kbyte L2 cache
Figure: Pressure coefficient Cp distribution.
Download IncompressibleLimit.tar.gz test problem folder. Uncompress this archive in the OpenFOAM work folder and execute AeroFoam . Cylinder_15k_M010 from terminal to start the simulation. Download.
