LES Filtering & Vortical Structures

This program is used for two purpose.

First it is applied to filter the fully-developed channel DNS data ( Re_tau = 395 ). Gaussian filter is used to filter DNS data.

Second it is used to get vortical structures from three different identification schemes

• Q criteria ( Haller.1988 )
• Lambda_2 criteria ( Jeong.1995 )
• Lambda_ci criteria ( Zhou.1999 )

0. Related papers & data

• Related paper : https://www.dropbox.com/s/osqskke88qgzow7/Turbulence%20Modeling%20-%20Project2.pdf?dl=0
• Related report : https://www.dropbox.com/s/3b180nsfyvw7gkj/report.pdf?dl=0
• Example data : https://www.dropbox.com/s/241nuubybzb8tgg/instantaneous_velocity_field_re644.plt?dl=0

1. Setting for LES_Filtering code

• Make 'RESULT' folder
• Add 3D Velocity data (u,v,w in x,y,z direction) ( tecplot format ) to RESULT folder
• Change settings in LES_Filtering_setup.f90 code only
  • Set file name variable ( file_name )
  • Set the number of meshes ( Nx,Ny,Nz )
  • Set the filter width constant ( FW )
  • Set Y-slice point ( N,YP )
  • Set Statistic type ( VS_ONLY )
  • Set vortical structure identification scheme ( VS_CASE )
  • Set the number of filter ( FILTER_OX )
    • If you want to make only vortical structure, set Filter_OX = 0, VS_ONLY = 2
    • If you want to get eddy viscosity and Smargorinsky coefficient, set FILTER_OX =2, VS_ONLY = 0 or 1.
  • Set Y sorting order ( Y_ORDER)
    • Whether the Y is saved in ascending or descending order.

2. Output files

• Filtered mean velocities ( 3D field, Y slice contour, Y profile )
• Filtered residual stress ( Y slice contour, Y profile )
• Filtered strain rate ( Y slice contour, Y profile )
• Filtered rotation rate ( Y slice contour, Y profile )
• Filtered eddy viscosity ( Y slice contour, Y profile )
• Filtered Smargorinsky coefficient ( Y slice contour, Y profile )
• Vortical Structures

3. Code composition

• LES_filtering_main.f90
• LES_filtering_module.f90
• LES_filtering_setup.f90
• LES_filtering_read.f90
• LES_filtering_filter.f90
• LES_filtering_second_filter.f90
• LES_filtering_output.f90
• LES_filtering_eig33.f90
• Vortical_Structures.f90