Case Definition

Moving Reference Frame

GRESSIER Jérémie — 2011-02-17T21:30:00Z

Since r713, it is possible to define a Moving Reference Frame (MRF) attached to the mesh. Equations are solved with the MRF velocities. External forces are modeled according to the MRF definition.

The MRF definition is done with a specific BLOCK:MRF definition.

The current MRF type are

`ROTATION`

BLOCK:MRF
 NAME = my_rotation ! optional
 TYPE = ROTATION
 CENTER = ( 5., 2., 0.) ! default is ( 0., 0., 0.)
 AXIS = ( 0., 0., 1.) ! default
 OMEGA_RPM = 600. ! 600 round per minute ~ 62.8 rad/s
 ENDBLOCK

`OSCILLATING_ROTATION`

BLOCK:MRF
 NAME = my_rotation ! optional
 TYPE = OSCILLATING_ROTATION
 CENTER = ( 5., 2., 0.) ! default is ( 0., 0., 0.)
 AXIS = ( 0., 0., 1.) ! default
 OMEGA_RPM = 600. ! 600 round per minute ~ 62.8 rad/s (default is 0)
 OSC_ANGLE = 10. ! max angle deviation (degree)
 OSC_PERIOD = .01 ! oscillating period (second)
 ENDBLOCK

Boundary conditions : compressible flow

GRESSIER Jérémie — 2011-02-09T12:00:00Z

Some parameters denoted symbolic function can be defined as symbolic functions which can depend on x, y, z and sometimes t.

Wall conditions

For compressible flows, wall conditions can be applied according to the type

`ADIABATIC_WALL`

wall condition with adiabatic energy condition

`ISOTHERMAL_WALL`

An additional WALL_TEMP= is required as an uniform imposed temperature.

`FLUXSET_WALL`

An additional WALL_FLUX= is required as an uniform imposed flux (W/m2).

For each of them, a WALL_VELOCITY= can be defined.

Inflow conditions

There are currently two types of in-flow boundary conditions

Subsonic inflow

BLOCK:BOCO
 FAMILY = my_mesh_tag
 TYPE = SUBSONIC_INLET
 PI = 
 TI =  or S = 
 DIR_X= 
 DIR_Y= 
 DIR_Z= 
 ENDBLOCK

Supersonic inflow

BLOCK:BOCO
 FAMILY = my_mesh_tag
 TYPE = SUPERSONIC_INLET
 PI =  ! (total or stagnation pressure)
 TI =  ! (total or stagnation temperature)
 MACH= 
 DIR_X= 
 DIR_Y= 
 DIR_Z= 
 ENDBLOCK

Entropy S is defined by PS/RHO^gamma

Direction of velocity can also be defined directly with

DIRECTION = (nx, ny, nz) ! 3 components

but only as constant components instead of DIR_* symbolic functions.

Outflow conditions

Like inflow conditions, there are currently two types of out-flow boundary conditions

Subsonic outflow

BLOCK:BOCO
 FAMILY = my_mesh_tag
 TYPE = SUBSONIC_OUTLET
 P =  ! (static pressure)
 ENDBLOCK

Supersonic outflow

Although no user parameter is applied, the following definition must be specified.

BLOCK:BOCO
 FAMILY = my_mesh_tag
 TYPE = SUPERSONIC_OUTLET
 ENDBLOCK

Mesh import

GRESSIER Jérémie — 2010-05-28T15:00:00Z

Typhon can import

CGNS files (legacy mesh import, see CGNS import for further details).
TYPHON internal format from a mesh file (.tym) or a solution (.tys)

In main.rpm parameter file, one can specify

BLOCK:MESH
 FORMAT = CGNS or TYPHON
 FILE = "my_mesh.cgns"

ENDBLOCK

One can specify some options :

SCALE = in order to scale all coordinates of the mesh
coordinates can be modified through a set a symbolic function (see mesh deformation)
MORPH_X =
MORPH_Y =
MORPH_Z =
SPLIT = ISO-TRI | SVM* for isotropic refinement of triangles or SVM-like splitting (see SVM article). For ISO-TRI, one can apply the refinement recursively with NSPLIT = (default : 1)

Initialization : compressible flow

GRESSIER Jérémie — 2009-09-03T20:30:00Z

Initial conditions for compressible flow solver is defined in BLOCK:INIT section. One can use

the solution is the CGNS mesh file with TYPE=CGNS
the solution is TYPHON internal format with TYPE=TYPHON or TYPE=TYS
or user-defined fields (default) with TYPE=DEFINITION where symbolic functions of X,Y,Z can be used.

Example (Lamb vortex definition) :

BLOCK:INIT
 P = 1.E5 - 1.161*900/2*exp(1-(X*X+Y*Y)/4)
 TI = 300
 VX = 20-30*Y/2*exp(0.5*(1-(X*X+Y*Y)/4))
 VY = 30*X/2*exp(0.5*(1-(X*X+Y*Y)/4))
 VZ = 0.
 ENDBLOCK

Combinations of quantities could be

static or stagnation pressure P, PI
density, static or stagnation temperature DENSITY, T, TI
velocity as
- components VX, VY, VZ
- Velocity magnitude and direction VELOCITY, DIRECTION
- Mach magnitude and direction MACH, DIRECTION

Probes

GRESSIER Jérémie — 2009-06-19T09:00:00Z

Probes definitions are used to compute a scalar value from the solution. It only currently can compute a user-defined quantity from internal cells at each end of cycle.

Probes are defined in main.rpm with the following syntax [1] :

BLOCK:PROBE
 NAME = m_probe_name
 TYPE = VOL_MIN | VOL_MAX | VOL_AVERAGE
 QUANTITY = 
 ENDBLOCK

In the symbolic function, allowed variables are

X, Y, Z
RHO, PS, V (magnitude), V_X, V_Y, V_Z for Navier-Stokes solver
TS (temperature) for Heat transfer solver

Each output is written in m_probe_name.tmon file.

[1] available in r664

Boundary conditions : periodicity

GRESSIER Jérémie — 2009-05-13T07:00:00Z

In main.rpm file, one must define first the periodicity :

translation periodicity

BLOCK:PERIODICITY
 NAME = (name)
 TYPE = TRANSLATION
 TRANSLATION = (vector)
 ENDBLOCK

rotation periodicity

BLOCK:PERIODICITY
 NAME = (name)
 TYPE = ROTATION
 ROTATION_CENTER = (vector)
 ROTATION_AXIS = (vector)
 ROTATION_ANGLE = (degree) or ROTATION_NUMBER = (n) (angle = 360/n)
 ENDBLOCK

One can then define one or several periodic connections with :

BLOCK:CONNECTION
 FAMILY1 = (one side mark)
 FAMILY2 = (other side mark)
 TYPE = PERIODIC
 PERIODICITY = (name of block:periodicity)
 ENDBLOCK

Note that the periodicity defines a direction from FAMILY1 to FAMILY2.

Outputs

GRESSIER Jérémie — 2009-05-12T09:30:00Z

Outputs file are currently managed with main.rpm file. One can defined either

an output of the zone through BLOCK:OUTPUT definition
- output format FORMAT=TYPHON|CGNS|VTK|VTK-BIN
- output filename FILE="myfile" [1]
- output cycle frequency PERIOD=n
- for TYPHON format, one can choose MESH=SHARED (default) to save disk space or MESH=FULL to ensure mesh writing with the solution

a history of boundary condition with additional options in BLOCK:BOCO

Note that an automatic output is triggered at the end of computation in TYPHON internal format. This file name is restart.tys.

TYPHON internal format can be exported to other formats with some post-processing tools (see associated CFDTOOLS)

[1] the extension is automatically added, .nnnn suffix is added if multiple files are needed for periodic output