FreeCASE - Free(dom) Computational AeroServoElasticity |
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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 = 1e-5 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.
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