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

Pitching NACA 64A010

In this section we present the numerical results of AeroFoam solver for a very simple 2D aeroservoelastic test problem, such as the inviscid compressible unsteady flow around a pitching NACA 64A010 airfoil.

Problem definition

  • Domain:
    • Internal NACA 64A010 airfoil subdomain with chord c = 1 m
    • External circular subdomain with radius Roo = 20 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 = 0.796
    • Angle of attack alpha = 0 deg
  • Boundary conditions:
    • Transpiration boundary conditions on internal subdomain to simulate, without actually deforming the mesh runtime, the airfoil forced sinusoidal pitching motion
    • Riemann boundary conditions on external subdomain
  • CAE2D toolbox:
    • Body reference frame to compute the aerodynamic loads
    • Aerodynamic reference length La = c/2 = 0.5 m
    • Elastic axis dimesional coordinates xEA = 0.248 m and yEA = 0 m
    • Steady-state solution with the CAE2D toolbox option solutionType = 0
    • Unsteady sinusoidal pitching forced motion of amplitude deltaAlpha = 1.010 deg and a reduced frequency k = w*La/Uoo = 0.202 with the CAE2D toolbox option solutionType = 1


Figure: Problem definition.

Space and time discretization

  • Space discretization:
    • Mesh created with Gmsh
    • # of triangular cells Nv = 2920
    • # of nodes Nn = 3144
  • Time discretization:
    • Total simulation time for steady-state solution endTime = 0.3 s
    • Total simulation time for unsteady solution endTime = 1 s
    • Timestep deltaT = 2.5e-6 s
    • Maximum Courant number maxCo = 1.95


Figure:
Computational grid.

Numerical results

  • Comparison with Flo3xx solver and AGARD 702 report experimental results
  • Single iteration CPUtime = 0.02 s on AMD64 3500+ desktop PC with AMD Athlon 64 2.2 GHz CPU, 1 Gbyte RAM, 512 Kbyte L2 cache


Figure:
Cycling to limit cycle.



Figure: Pressure coefficient Cp contours.

Download

  • PitchingAirfoil.tar.gz test problem folder. Uncompress this archive in the OpenFOAM work folder and execute AeroFoam . NACA64A010_3k_M0796 from terminal to start the simulation. Download.


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