FreeCASE - Free(dom) Computational AeroServoElasticity
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### 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.