Aileron buzzIn this section we present the numerical results of AeroFoam
solver for a 2D aeroservoelastic test problem, such as the
simulation of the inviscid buzz fluid structure interaction phenomenon on a NACA 65213 airfoil. Problem definition Domain:
 Internal NACA 65213 airfoil subdomain with chord c = 1.4722 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 = 0.839
 Angle of attack alpha = 0 deg
 Trailing edge control surface deflection delta = 0 deg
 Boundary conditions:
 Transpiration
boundary conditions on internal subdomain to simulate, without
actually deforming the mesh runtime, the trailing edge control surface free motion
 Riemann boundary conditions on external subdomain
 CAE2D toolbox:
 Body reference frame to compute the aerodynamic loads
 Aerodynamic reference length La = c/2 = 0.7361 m
 Elastic axis dimesional coordinates xEA = 0.248 m and yEA = 0 m
 Hinge axis dimensional coordinates xHinge = 0.368 m and yHinge = 0 m
 Moment of inertia around the hinge axis I_dd = 0.55363 kg*m^2
 Structural damping C_dd = 0 Nms
 Structural stiffness K_dd = 0 Nm
 Steadystate solution with the CAE2D toolbox option solutionType = 0
 Unsteady trailing edge control surface free motion with the CAE2D toolbox option solutionType = 1
Figure: Problem definition.
Space and time discretization Space discretization:
 Mesh created with Gmsh
 # of triangular cells Nv = 8712
 # of nodes Nn = 9054
 Time discretization:
 Total simulation time for steadystate solution endTime = 0.3 s
 Total simulation time for unsteady solution endTime = 1 s
 Timestep deltaT = 4e6 s
 Maximum Courant number maxCo = 1.95
Figure: Computational grid. Numerical results Comparison with FLUENT solver (many thanks to Edoardo Biganzoli) and NASA TP 3197 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: Trailing edge control surface free motion at Moo = 0.839. Figure: Pressure coefficient Cp contours. Download AileronBuzz.tar.gz test problem folder. Uncompress this archive in the OpenFOAM work folder and execute AeroFoam . NACA65213_9k_M0839 from terminal to start the simulation. Download.
