FreeCASE - Free(dom) Computational AeroServoElasticity

Last update:
January 15. 2016 14:05:15

Incompressible limit

In 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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