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
 Steadystate 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 steadystate solution endTime = 0.3 s
 Total simulation time for unsteady solution endTime = 1 s
 Timestep deltaT = 2.5e6 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.
