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Wind 3.0 --> Wind 4.0 Changes
The following list summarizes the principal changes made between the
Wind Version 3.0 and 4.0 code releases.
The following changes have been made to the Wind code itself.
- The Spalart
Detached Eddy Simulation (DES) turbulence model
is now available for unsteady three-dimensional flows.
The DES model reduces to the standard Spalart-Allmaras model
near viscous walls, where the grid is refined and has a large
aspect ratio, but acts like a Large Eddy Simulation (LES) model
away from the boundary, where the grid is coarser and has an
aspect ratio of order one.
- A combined
SST and Large Eddy Simulation (LES) turbulence model
is now available for unsteady flows.
The combined model reduces to the standard SST model in high
mean shear regions (e.g., near viscous walls), where the grid is
refined and has a large aspect ratio unsuitable for LES models.
As the grid is traversed away from high mean shear regions, it
typically becomes coarser and more isotropic, and the combined
model smoothly transitions to an LES model.
- The coding for the Spalart
turbulence model has been rewritten, eliminating some additions
that are no longer recommended.
The current model is now the same as in Spalart's original 1992
In addition, the
turbulence level may be specified.
The previously-coded model may be recovered in Wind 4.0 by using
TEST 21 2.
- You can now specify the number of
sub-iterations for the
Navier-Stokes equation group for each "iteration per cycle".
This allows the turbulence model equations to be solved without
simultaneously solving the Navier-Stokes equations.
keyword for additional details and an example.
- Switching turbulence models during a restart has been improved.
- The empirical bleed model of
Mayer and Paynter has been added.
It computes the local bleed based on the local flow conditions,
bleed plenum pressure, porosity, and empirical data for the sonic
- Two new compressor
face boundary conditions have been added.
compressor face model computes unsteady acoustic
reflections from a compressor face subjected to acoustic and
compressor face model is basically the same, except with
a different expression for the acoustic response coefficient
in subsonic flow.
- A non-reflecting,
subsonic outflow boundary condition has been added.
- The default explicit operator now uses high-order Roe coupling at
zone boundaries by default.
High-order Roe coupling now applies for additional explicit
operators, as described with the
For standard Roe coupling, you must specify COUPLING MODE ROE
Note that when using Wind 4.0 and restarting from solutions
computed with Wind 3.0 that used
the default coupling (standard Roe), you may encounter transients
in the solution or convergence rate if the new default coupling
(high-order Roe) is used.
In these cases, you may want to either specify standard Roe coupling,
or switch to a lower CFL number or time step until the transients
- A double-fringe capability
has been added for overlapping grids, providing higher-order
overlapped boundary coupling.
- An actuator disk
may now be located at a boundary that couples to another
boundary in the same zone.
- The rotating reference
frame feature has been extended to allow different
rotation rates in different zones.
averaged zone interface coupling procedure allows the
coupling of adjacent zones with different rotation rates.
- Boundary conditions are now only applied when consistent with the
This only affects corners, where there are often multiple
boundary conditions specified.
As an example, if a wall boundary at j = 1 meets an
outflow boundary at i = imax, only the
wall boundary condition is applied.
The former behavior may be specified using
TEST 61 2.
- Wall function boundary
conditions may now be used for flows with equilibrium and
- The default crossflow CFL
factor is now 2.0 for three-dimensional flow, and 1.0 for
two-dimensional and axisymmetric flow.
- The reacting species in a finite-rate chemistry solution may
now be specified on a zonal basis, using the OMIT
keyword in the
- You can now control the frequency with which residuals and cycle
time information are written into the list output (.lis) file.
keywords for details.
- Wind now supports CGNS
files for grid and flow field data.
- Dependent variables are now double precision.
Last updated 4 Nov 2002