Name 
Type 
Default 
Description 








Flow parameters 




Tfin 
double [s] 
1.0 
defines the (physical) timespan of the simulation 
reynolds 
double 
10.0 
is the dimensionless Reynoldsnumber which describes the ratio
between inertia and viscous forces in the flow 
nuC 
int 
0 
the paramter nuC sets the number of species to be transported with the flow. For each species, a
diffusion constant has to be specified in a commaseparated list after nuC, i.e. the line has to look like
nuC
where is an integer specifying the number of species and
is a double value which stands for the diffusion parameter of the ith species. You have to make sure that you also specify
initial conditions using the keyword cheminit. Details on how to specify initial and boundary conditions are given in
section 
gx 
double [m/s] 
0.0 
component of external volume force in () (or
in () if the temperature is calculated). In the latter case
is computed from by means of () 
gy 
double [m/s] 
0.0 
Same as gx for the component 
gz 
double [m/s] 
0.0 
Same as gx for the component 
froude 
double 
1.0 
the Froudenumber is a dimensionless number describing the ratio between
inertial and gravitational forces 
beta 
double [1/K] 
1e4 
volume expansion coefficient in equation () 
TempRef 
double [K] 
273.0 
reference temperature in () 
prandtl 
double 
1.0 
the Prandtlnumber is a dimensionless number describing the ratio between momentum and
heat transfer in the fluid 
Timestep control 




deltmax 
double [s] 
1.0 
upper bound for 
tfconv 
double 
0.1 
security factor for the timestep restriction arising from the convective terms.
In every step, will be set less or equal than
where denotes the set of cells
in 
tfdiff 
double 
0.2 
security factor for the timesteprestriction arising from the diffusive terms.
In every step, will be set less or equal than
and

Data output 




prstep 
int 
20 
defines when to write the computed values to the binary file. Each prstepth
timestep the current solution is written to the binary file(the file is overwritten) 
TimePrintStep 
string 
 
defines an interval (in physical time) after which the solution should be written to files
in a directory specified by TargetDirectory.
If TimePrintStep is not specified, no output will be generated. 
TargetDirectory 
string 
 
specifies the directory(absolut pathname) where the files
generated by TimePrintStep should be stored 
Parameters controlling numerical methods 




TimeDis 
string 
EU1 
defines the time discretization to be used. Possible values are
EU1 for first order explicit EulerMethod, AB2 for second order explicit AdamsBashforthMethod,
RK2 for second order RungeKuttamethod and RK3 for third order RungeKuttamethod.
Remark: The RungeKuttamethod of third order is only available for the time derivatives in
equations () and (),
setting TimeDis to RK3 results in application of the RungeKuttamethod of second order to
the other time derivatives 
ConvectiveTerms 
string 
VONOS 
defines the discretization scheme to be used for the convective terms.
Possible values are DC (DonorCell, 1st/2nd order), HLPA (Hybrid LinearParabolic Approximation, 1st/2nd order),
QUICK (Quadratic Upwind Interpolation for Convective Kinematics, 2nd order), SMART
(Sharp And Monotonic Algorithm for Realistic Transport, 2nd order) and VONOS
(VariableOrder NonOscillatory Scheme, 2nd order) 
PoissonSolver 
string 
BiCGStab 
set the method for solution of the linear system arising from
discretization of the pressure poisson equation. Possible values are SOR, SSOR, RedBlack, 8ColorSOR, 8ColorSSOR and
BiCGStab (preconditioned with JacobiMethod) 
alpha 
double 
1.0 
defines the blending parameter in the convex combination of
the central difference/upwind discretization of the convective terms of .
means pure upwind and
results in pure central difference discretization 
alphaTC 
double 
1.0 
same as alpha, but for convective terms in the transport
equation used for computation of temperature and scalars 
Parameters for the linear solver 




itermax 
int 
100 
defines the maximal number of iterations in the linear solver
(BiCGStab,SOR, SSOR etc.) 
eps 
double 
0.001 
defines the stopping criterion for the iterations in the linear solver.
The parameter eps is the upper bound for the residual of the poisson equation, i.e. the iterations
are stopped if
Here, is the set of all fluid cells in and
is the cardinality of .
and denote the discrete Laplacian and gradient operator. 
omega 
double 
1.7 
sets the relaxation parameter for the SORtype solvers 
Boundary conditions 




periodboundx 


sets periodic boundary conditions in direction of coordinate 
periodboundy 


same as periodboundx only for the coordinatedirection 
periodboundz 


same as periodboundx only for the coordinatedirection




