- SG Chumakov, A priori study of subgrid-scale flux of a passive scalar in turbulence, Phys. Rev. E, 78 15563 (2008)
- SG Chumakov, Scaling properties of subgrid-scale energy dissipation, Phys. Fluids, 19 058104 (2007)
- http://github.com/schumakov/hit3d
With any questions, contact the project owner or visit http://chumakov.info
HIT3D is a pseudo-spectral DNS code for simulation of homogeneous isotropic incompressible turbulence in three dimensional space. It is aspiring to be a standard code for DNS of isotropic homogeneous turbulence in triple-periodic box. The code
- is written in Fortran 90
- is parallelized using MPI
- uses FFTW3 is used for Fourier transform (http://www.fftw.org)
- can employ Lagrangian particles (tracers) to gather Lagrangian statistics
- is released under the GNU Public License.
The code is written in Fortran 90 and uses the two open libraries:
- Open-MPI (www.open-mpi.org) - suggested MPI implementation. Other MPI implementations such as MVAPICH and Intel MPI whould work as well. The code uses standard MPI communication calls.
- FFTW3 (www.fftw.org)
http://chumakov.info/codes-hit3d.php
- First, edit the Makefile:
- add a section that corresponds to the name of your machine. Ideally it should be a wrapper from your MPI implementation.
- define the name of the F90 compiler
- define FCFLAGS and LDFLAGS. They should include the include directories, the flags that link FFTW3 and MPI implementation.
- Run "gmake"
The directory scripts provides some examples of the batch job submission files.
00_example.ina sample input filesnapshot.gpa Gnuplot instruction file that creates two plots that can get attached to the notification emails
NX,NY,NZ Number of grid points in one dimension.
The grid will be NX x NY x NZ. The physical dimensions will be 2*pi x 2*pi x 2*pi
ITMIN The timestep number of the restart file. The restart files have names
such as "test__this.64.123456". Here, "test__this" is the run name,
"64" signifies that the file is written with double precision and
"123456" is the timestep number. If the ITMIN is set to 0, the
subroutine that defines the initial conditionis for the flow is called.
ITMAX The maximum number of timesteps in the simulation.
IPRNT1 How often to generate the statistics.
IPRNT2 How often to write restart files
IWRITE4 How often to write the real*4 files that are used for post-processing.
TMAX The runtime of the simulation (not the wallclocok time)
TRESCALE The time at which to rescale the velocity. This is used in decaying
simulations when we want to establish some correlations first and
then rescale the velocity field so it has higher kinetic energy.
TSCALAR When to start moving the passive scalars.
flow_type Parameter that switches the flow type
0 - decaying turbulence
1 - forced turbulence
RE The local Reynolds number (1/nu, where nu is dynamic viscosity)
DT The timestep.
If DT is negative, then the timestep is fixed to be (-DT)
If DT is positive, the timestep is found from the stability
criteria for the time-stepping scheme that is used.
ISPCV1 Initial spectrum type (see init_velocity.f90)
mv1 initial infrared exponent in the spectrum
wm0v1 initial peak wavenumber in the spectrum
force_type The type of the forcing that is applied for the case of
forced turbulence.
1 - forcing from Michaels PRL paper (PRL #79(18) p.3411)
So far no other forcing has been implemented
KFMAX The upper bound for the forcing band in the Fourier space.
FAMP The magnitude of the forcing (usually set to 0.5)
det_rand The parameter that switches the random generation for the
random seeds for the code.
DEFUNCTIONAL. In the current version of the code, the seeds for the
random number generator are fixed and are taken from the input file.
The fixed seeds have the effect of producing the initial data that
looks similar for different resolutions (the large features of
initial flow in 32^3 simulation will look similar to the large features
of a 1024^3 simulation if the seeds are the same).
RN1, RN2, RN3 - random number seeds
DEALIAS The parameter that switches between the dealiasing algorithms.
0 - the standard 3/2-rule (or 2/3 rule). Faster computations, but
fewer modes.
1 - the phase shift combined with truncation. This retains much more
modes than the 2/3-rule, while increasing the computations 60% or so.
The most economical mode for DNS in terms of flops per the number of
Fourier modes in the resulting data.
np The number of Lagrangian particles
* particle tracking mechanism:
0 - trilinear interpolations
1 - 4-point cubic interpolation
time_p time in the simulation when to release the particles in the flow
particle_filter_size
The particles can be advected by fully resolved field or by locally averaged
field. The filter size determines the size of the filter that is applied
to the velocity field before computing the particles' velocities.
(set to 0.0 to disable)
les_model The LES model. Currently not debugged and should not be used.
NUMS The number of passive scalars to carry around
The last section contains the parameters of the passive scalars. Each scalar
has four parameters: the type, Schmidt number, infrared exponent, peak wavenumber and
reaction rate.
The first parameter is the scalar type.
TYPE:
0 The scalar that is forced by the mean gradient.
1-9 The initial conditions for the scalar are generated using Fourier space.
1: Exponential spectrum
2: von Karman spectrum
3: double-delta PDF
>10 The initial conditions for the scalar are generated in the real space.
11: single slab of the scalar.
12: two slabs of the scalar
13: 1-D sinusoidal wave of the scalar
The second and third parameters are Schmidt number and peak wavenumber.
Peak wavenumber is used when initializing scalars in Fourier space.
The fourth parameter (reaction rate) is not used in this version of the code.
Copyright (C) 2006-2024 Sergei Chumakov, Natalia Vladimirova, Misha Stepanov
The code is distributed under the terms of GNU GPLv3 license.
You can read the full text of the license at http://www.gnu.org/licenses/gpl.html
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.