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

Aileron buzz

In 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
    • Steady-state 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 steady-state solution endTime = 0.3 s
    • Total simulation time for unsteady solution endTime = 1 s
    • Timestep deltaT = 4e-6 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.


Powered by cmsimple.dk