FreeCASE - Free(dom) Computational AeroServoElasticity
Last update:
January 15. 2016 14:05:15

Thin airfoil

In this section we present the numerical results of AeroFoam solver for a 2D aerodynamic test problem, such as the inviscid compressible unsteady flow around a thin airfoil.

Problem definition

  • Domain:
    • Internal very thin (t/c = 1/100) airfoil subdomain with chord c = 1 m
    • External circular subdomain with radius Roo = 25 m >>  c
  • 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 = 0.5 - 0.7 - 1.0 - 1.2
    • Angle of attack alpha = 1 deg
  • 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 = 6498
    • # of nodes Nn = 6740
  • Time discretization:
    • Total simulation time endTime = 0.05 s
    • Timestep deltaT = 5e-6 - 4e-6 - 2.5e-6 - 2e-6 s
    • Maximum Courant number maxCo =  1.95


Figure:
Computational grid.

Numerical results

  • Comparison with exact solution of small disturbances theory
  • Single iteration CPUtime = 0.045 s on AMD64 3500+ desktop PC with AMD Athlon 64 2.2 GHz CPU, 1 Gbyte RAM, 512 Kbyte L2 cache


Figure: Time history of the lift coefficient slope CL/alpha.

Download

  • ThinAirfoil.tar.gz test problem folder. Uncompress this archive in the OpenFOAM work folder and execute AeroFoam . ThinAirfoil_7k_M050_a1 from terminal to start the simulation. Download.


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