Airfoil

LSB-s7003

It is one of the most complex and intersting case. The user has to create a proper mesh in gmsh setting the following physical boundaries:

inlet for the inlet
outlet for the outlet
airfoil for the airfoil walls
limits for the top and bottom boundaries

.geo file

In the folder models/ is possible to find some .msh file created using gmsh both for 3D and 2D simulations. In the folder models/geo are available some .geo that can be open in gmsh. Different parameters can be modified: angle of attack, domain dimension, mesh divisions.

The velocity at the inlet is incresed from 0.0 arriving to the target value u_in at :t_endramp. This increase the numeric stability. If :t_endramp = :t0 the velocity at the inlet will be immediately :u_in. For numeric stability is better to keep u_in = [1.0,0.0,0.0], then fix the Reynolds and so the viscosity will be automatically computed as: ν = 1/Reynolds

The pressure is set 0.0 at the outlet section. The velocity on the limits is set equal to the one at inlet.

Suggested workflow

3D LES are heavy and it is possible to experience divergence issues. It is suggested to use one of the two initilization tecniques: Velocity ramping or Boundary layer initialization. For visualize the results, please refer to

Velocity ramping

By setting t_endramp > t0 automatically the code will create an inlet velocity which will increase linearly in time up to the u_in target value.

using PartitionedArrays
using MPI
using SegregatedVMSSolver
using SegregatedVMSSolver.ParametersDef
using SegregatedVMSSolver.SolverOptions

Calling the dependencies

t0 =0.0
dt = 1e-3
tF = 5e-3

Re = 10
D = 2
rank_partition = (2,2)
airfoil_mesh_file = joinpath(@__DIR__,"..", "assets", "sd7003s_2D_test.msh")

timep = TimeParameters(t0,dt,tF)

physicalp = PhysicalParameters(Re=Re)
solverp = SolverParameters(M=2)
exportp = ExportParameters(printinitial=false,printmodel=false,name_tags=["airfoil"], fieldexport=[["uh"]])

meshp= MeshParameters(rank_partition,D,airfoil_mesh_file)
simparams = SimulationParameters(timep,physicalp,solverp,exportp)

Setting the parameters. This simulation will not converge, we are not using a suitable solver which needs hypre.

Defining the stabilizatin problem and the simualtion case

sprob = StabilizedProblem(VMS(1))
simcase = Airfoil(meshp,simparams,sprob)

Solve in Sequential - on 1 processor not using MPI, useful for debug.

 SegregatedVMSSolver.solve(simcase,with_debug)

Solve in MPI - for HPC computing

 SegregatedVMSSolver.solve(simcase,with_mpi)

Then in bash give the command. Check the MPI section for more details

 mpiexecjl -n 4 julia --project=. run_mysimulation.jl

Boundary Layer initialization

Details are provided in the dedicated section.