real abux:
This optional information parameter can be specified with
real abux f=E15.8 b=4 n='hydrogen abundance (number fraction)' u=1 &
c0='standard solar mixture'
0.90851003E+00
It has no practical consequences because the actually used
chemical composition is determined by the files for equation of state and opacity.
real abuy:
This optional information parameter can be specified with
real abuy f=E15.8 b=4 n='helium abundance (number fraction)' u=1 &
c0='standard solar mixture'
0.90850003E-01
It has no practical consequences because the actually used
chemical composition is determined by the files for equation of state and opacity.
real qmol:
This optional information parameter can be specified with
real qmol f=E15.8 b=4 n='mean molecular weight' u=u &
c0='standard solar mixture'
0.13018000E+01
It has no practical consequences because the actually used
chemical composition is determined by the files for equation of state and opacity.
real gamma:
This optional information parameter can be specified with
real gamma f=E15.8 b=4 n='Adiabatic coefficient' u=1 &
c0='0.0/1.6666666666666/1.4'
0.0
It has no practical consequences because the actually used
chemical composition is determined by the files for equation of state and opacity.
real c_visneu1:
real c_visneu1 f=E15.8 b=4 &
n='Linear viscosity parameter (von Neumann-Richtmyer type)' u=1
0.0
real c_visneu2:
real c_visneu2 f=E15.8 b=4 &
n='Quadratic viscosity parameter (von Neumann-Richtmyer type)' u=1
0.0
real c_radkappasmooth:
In the LHDrad module the opacity along each ray can be smoothed.
The amount of smoothing can be set e.g. with
real c_radkappasmooth f=E15.8 b=4 n='Opacity smoothing parameter' u=1 &
c0='0.0: no smoothing, 0.25: light smoothing, 0.666: strong smoothing'
0.0
The smoothing can perhaps reduce the noise in the intensity images somewhat but
has no general beneficial effect and should usually not be used.
real c_radtsmooth:
In the LHDrad module the 3D temperature array can be smoothed.
The amount of smoothing can be set e.g. with
real c_radtsmooth f=E15.8 b=4 n='Temperature smoothing parameter' u=1 &
c0='0.0: no smoothing, 0.5: reasonable smoothing, 1.0: max. smoothing'
0.0
The smoothing can sometimes reduce the noise in the intensity images
but causes/amplifies some anomalies of the radiative Greens function:
Some cool cell just above the sharp sub-photospheric temperature drop are not heated but cool
further down. Negative temperature spikes may result.
This smoothing should not be used anymore.
character radpressure:
In the LHDrad module
there exists a simple prescription for the radiative pressure
(reasonable in the optically thin)
which can be activated with
character radpressure f=A80 b=80 n='Radiation pressure mode' &
c0='on/off'
on
Allowed values are
on: Radiation pressure on.
off: Radiation pressure off.
The scheme is pretty slow and wrong in the optically thick. Do not use!
However, the SHORTrad version is much more advance and can be used,
even if it might require some more testing.
real c_radtintminfac:
In the LHDrad module:
The fraction the interpolated temperature (at a point on the ray)
may exceed the minimum temperature at its four neighbors on the HD grid
can be set e.g. with
real c_radtintminfac f=E15.8 b=4 &
n='Temperature interpolation parameter' u=1 &
c0='<1.0: only bilinear, 1.1: reasonable weighting between min. und bil.'
0.0
The introduction of this parameter was an attempt to reduce the negative (cooling)
effect of a single hot cell on its cool neighbors.
It should be switched off e.g. by setting it to 0.0.
integer dtimestep_out_fine:
This parameter can be specified but there is no corresponding output file in CO5BOLD yet.
integer dtimestep_out_fine f=I4 b=4 n='Output time step number' u=1 &
c0='dtimestep_out_fine<0 => no output'
-1
character outfile_fine:
The name of the file for the output of additional information
at regular (small) intervals
can be specified with e.g.
character outfile_fine f=A80 b=80 n='Output file name'
rhd.fine
Leaving it empty means that no file of this type is written.
Specifying it means the same (yet).
character outform_fine:
The format (see Sect. 4.3.1) of the files with frequent output
can be chosen e.g. with
character outform_fine f=A80 b=80 n='Output file format' &
c0='formatted/unformatted'
unformatted
Allowed values are
unformatted: (default) fast compact (possibly machine-dependent) output:
strongly recommended
formatted: slow (machine-independent) output, big files
This parameter can be specified but there is no corresponding output file in CO5BOLD yet.
character outconv_fine:
The conversion type (see Sect. 4.3.1) of the files with frequent output
can be specified e.g. with
character outconv_fine f=A80 b=80 n='Output file conversion' &
c0='ieee_4/ieee_8/crayxmp_8/native'
ieee_4
The allowed values depend on the machine.
Leaving this field empty means that the default is chosen that is build into the local UIO module.
If the type ieee_4 is supported (which is always the case, so far) it should be chosen.
This parameter can be specified but there is no corresponding output file in CO5BOLD yet.
real c_visdrag:
This viscosity parameter controls the drag force which is (if requested)
applied inside the hydrodynamics routines themselves.
It does not act on velocity gradients as usual viscosity but applies a force proportional to the
velocity itself (but with the opposite sign).
The amount can be specified e.g. with
real c_visdrag f=E15.8 b=4 &
n='Drag viscosity parameter' u=1
0.001
The value gives the fraction the velocity is reduced per time step.
Therefore, reasonable values lie between 0.0 and 1.0.
In almost every case the drag forces will be switched off (c_visdrag=0.0).
If e.g. strong pulsation have to be damped in the initial phase of a simulation
a value around 0.001-0.01 seems appropriate.
rhd_roe1d_slope_l01:
in rhd_hyd_module.F90,
(``rhd roe 1 dimension slope loop 01'').
Category: feature activation.
When this compiler switch is set,
a new extra stabilization mechanism can be activated:
If one of the reconstruction methods VanLeer, Superbee, or PP
(see Sect. 5.4.7) is activated, the slope can be reduced
(by averaging with the results from a MinMod reconstruction) by setting
c_slopered (see Sect. 5.4.7) to a positive non-zero value.
This can improve the stability without significantly
reducing the effective numerical resolution.
Switch values:
0: (default) no slope reduction.
1: slope reduction in case of expansion wave.
2: slope reduction in case of strong density contrast.
IDF:
in rhd_hyd_module.F90,
(``Integer Delta Flux'').
Category: performance enhancement.
Number of padding cells for flux-like variables. This number was introduced to check
whether the increase of the size of vectors for flux-like quantities (defined at
cell boundaries) can improve the performance (especially on a CRAY machine).
The gain is marginal (if present at all). The parameter is usually set to zero
or left undefined.
Values:
0: (default) no padding cells
1,2,3,...: extra padding cells
rhd_hyd_roe1d_l01:
in rhd_hyd_module.F90,
(``rhd hydrodynamics roe 1 dimension loop 01'').
Category: performance enhancement.
The computation of the Roe fluxes can be done by either of two sets of routines
to find the set which gives optimum performance (with essentially the same results).
Values:
0: (default) lots of small routines acting on scalars, inlining needed,
cache reuse is optimized
1: routines acting on arrays, more temporary arrays necessary,
vectorization is easier
