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

Laminar boundary layer

In this section we present the numerical results of AeroFoam solver for a 2D aerodynamic test problem, such as the viscous laminar flow over a flat plate.

Problem definition

  • Domain:
    • Rectangular channel of length L = 1 m and height h = 0.06 m 
  • Material:
    • Polytropic Ideal Gas (PIG)
    • Specific heat ratio gamma = 1.4
    • Gas thermodynamic constant R = 287.05 J/kgK
    • Sutherland's law to model dynamic viscosity - temperature law mu = mu(T)
    • Constant Prandtl number Pr = 0.72
  • Initial conditions: 
    • Thermodynamic pressure Poo = 101325 Pa
    • Temperature Too = 288.15 K
    • Velocity Uoo = 100 m/s
  • Boundary conditions:
    • SupersonicInlet boundary conditions on the inlet section (front and top walls)
    • ExtrapolatedOutlet boundary conditions on the outlet section
    • AdiabaticViscousWall boundary conditions on the bottom wall


Figure: Problem definition.

Space and time discretization

  • Space discretization:
    • Boundary layer mesh created with blockMesh
    • # of rectangular cells Nv = 2500
    • # of nodes Nn = 2601
  • Time discretization:
    • Total simulation time endTime = 0.025 s
    • Timestep deltaT = 5e-8 s
    • Maximum Courant number maxCo =  1.5


Figure:
Detail of the computational grid.

Numerical results

  • Comparison with Blasius numerical solution of thin boundary layer equations
  • Single iteration CPUtime = 0.03 s on AMD64 3500+ desktop PC with AMD Athlon 64 2.2 GHz CPU, 1 Gbyte RAM, 512 Kbyte L2 cache


Figure:
Velocity profiles.

Download

  • Blasius.tar.gz test problem folder. Uncompress this archive in the OpenFOAM work folder and execute AeroFoam . Blasius_3k_M030 from terminal to start the simulation. Download.



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