Initiator: solution Initialization Module

Preamble

Initiator module works on arrays (as defined in Converter) or on CGNS/python trees (pyTrees) containing grid information (coordinates must be defined).

This module is part of Cassiopee, a free open-source pre- and post-processor for CFD simulations.

For use with the array interface, you have to import Initiator module:

import Initiator as I

For use with the pyTree interface:

import Initiator.PyTree as I

List of functions

– CFD field initialisations

initConst(a[, adim, MInf, alphaZ, alphaY, ReInf])

Init a by a constant field.

initLamb(a[, position, Gamma, MInf])

Init a with a Lamb vortex of intensity Gamma and position (x0,y0).

initVisbal(a[, position, Gamma, MInf])

Init a with a Visbal vortex of intensity Gamma and position (x0,y0).

initScully(a[, position, Gamma, coreRadius, ...])

Init a with a Scully vortex of intensity Gamma, core radius coreRadius and position (x0,y0).

initYee(a[, position, Gamma, MInf])

Init a with a Yee vortex of intensity Gamma and position (x0,y0).

initWissocq(a[, position, Gamma, MInf])

Init a with Wissocq's vortex of intensity Gamma and position (x0,y0).

overlayField(a1, a2[, MInf])

Overlay the field of a1 and a2.

– Adimensioning

Adim.adim1([MInf, alphaZ, alphaY, ReInf, ...])

Return a state corresponding to adimensioning by density, sound speed and temperature.

Adim.adim2([MInf, alphaZ, alphaY, ReInf, ...])

Return a state corresponding to adimensioning by density, velocity and temperature.

Adim.adim3([MInf, alphaZ, alphaY, ReInf, ...])

Return a state corresponding to adimensioning by density, sound speed and temperature.

Adim.dim1([UInf, TInf, PInf, LInf, alphaZ, ...])

Return a dimensioned state specifying velocity, temperature and pressure.

Adim.dim2([UInf, TInf, RoInf, LInf, alphaZ, ...])

Return a dimensioned state specifying velocity, temperature and density.

Adim.dim3([UInf, PInf, RoInf, LInf, alphaZ, ...])

Return a dimensioned state specifying velocity, pressure and density.

– Mesh size

MeshSize.meshSize(UInf, RoInf, ReInf, LInf)

Return the height of first wall cell to match a certain y+.

Contents

CFD field initialisations

The input data defines a grid or a set of grids on which the solution has to be initialized.

The created field variables are the variables defined in the input data. If the five conservative variables are not present, then the default output variables are the coordinates and the conservative variables.

Initiator.initConst(a, adim='adim1', MInf=None, alphaZ=0., alphaY=0., ReInf=1.e8, loc='nodes')

Initialization by a constant field, given Mach number, incident flow angles and Reynolds number.

Exists also as in place version (_initConst) that modifies a and returns None.

Parameters:

  • a ([array, list of arrays] or [pyTree, base, zone, list of zones]) – input data

  • adim (string) – Name of adim (‘adim1’, ‘adim2’, ‘dim1’, …) - see Adimensioning section

  • MInf (float) – freestream Mach number

  • alphaZ (float) – Angle with respect to (0,Z) axe (in degrees)

  • alphaY (float) – Angle with respect to (0,Y) axe (in degrees)

  • ReInf (float) – Reynolds Number

  • loc (string) – created field localisation (‘nodes’ or ‘centers’) - only for pyTree interface

Return type:

Identical to a

Example of use:

# - initConst (array) -
import Converter as C
import Generator as G
import Initiator as I

NI = 100; NJ = 100
HI = 50./(NI-1); HJ = 50./(NJ-1)
a = G.cart((0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
a = I.initConst(a, MInf=0.8)
C.convertArrays2File([a], 'out.plt')

# - initConst (pyTree) -
import Converter.PyTree as C
import Generator.PyTree as G
import Initiator.PyTree as I

NI = 100; NJ = 100
HI = 50./(NI-1); HJ = 50./(NJ-1)
a = G.cart((0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
a = I.initConst(a, MInf=0.8, loc='centers')
C.convertPyTree2File(a, 'out.cgns')
Initiator.initLamb(a, (x0, y0), Gamma=2., MInf=0.5, loc='nodes')

Initialization of conservative variables by a 2D Lamb vortex at position (x0,y0), intensity Gamma and infinite Mach number MInf.

Exists also as in place version (_initLamb) that modifies a and returns None.

Parameters:

  • a ([array, list of arrays] or [pyTree, base, zone, list of zones]) – Input data

  • Gamma (float) – Intensity of vortex

  • MInf (float) – Mach number

  • loc – created field localisation (‘nodes’ or ‘centers’) - only for pyTree interface

Return type:

Identical to a

Example of use:

# - initLamb (array) -
import Converter as C
import Generator as G
import Initiator as I

NI = 100; NJ = 100
HI = 50./(NI-1); HJ = 50./(NJ-1)
a = G.cart((0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
a = I.initLamb(a, position=(25.,25.), Gamma=2., MInf=0.8)
C.convertArrays2File(a, 'out.plt')

# - initLamb (pyTree) -
import Converter.PyTree as C
import Generator.PyTree as G
import Initiator.PyTree as I

NI = 100; NJ = 100
HI = 50./(NI-1); HJ = 50./(NJ-1)
a = G.cart((0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
a = I.initLamb(a, position=(7.,7.), Gamma=2., MInf=0.8, loc='centers')
C.convertPyTree2File(a, "out.cgns")
Initiator.initVisbal(a, (x0, y0), Gamma=2., MInf=0.5, loc='nodes')

Initialization of conservative variables by a 2D Visbal vortex at position (x0,y0), intensity Gamma and infinite Mach number MInf.

Exists also as in place version (_initVisbal) that modifies a and returns None.

Parameters:

  • a ([array, list of arrays] or [pyTree, base, zone, list of zones]) – Input data

  • Gamma (float) – Intensity of vortex

  • MInf (float) – Mach number

  • loc – field localisation (‘nodes’ or ‘centers’) - only for pyTree interface

Return type:

Identical to a

Example of use:

# - initVisbal (array) -
import Converter as C
import Generator as G
import Initiator as I

NI = 100; NJ = 100
HI = 50./(NI-1); HJ = 50./(NJ-1)
a = G.cart( (0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
a = I.initVisbal(a,position=(25.,25.), Gamma=2., MInf=0.8)
C.convertArrays2File([a], 'out.plt')

# - initVisbal (pyTree) -
import Converter.PyTree as C
import Generator.PyTree as G
import Initiator.PyTree as I

NI = 100; NJ = 100
HI = 50./(NI-1); HJ = 50./(NJ-1)
MachInf = 0.8

a = G.cart((0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
z = I.initVisbal(a, (3.,3.), 2., MachInf, loc='centers')
C.convertPyTree2File(z, 'out.cgns')
Initiator.initScully(a, (x0, y0), Gamma=2., coreRadius=1., MInf=0.5, loc='nodes')

Initialization of conservative variables by a 2D Scully vortex at position (x0,y0), intensity Gamma and infinite Mach number MInf.

Exists also as in place version (_initScully) that modifies a and returns None.

Parameters:

  • a ([array, list of arrays] or [pyTree, base, zone, list of zones]) – Input data

  • Gamma (float) – Intensity of vortex

  • coreRadius (float) – radius of vortex core

  • MInf (float) – Mach number

  • loc – field localisation (‘nodes’ or ‘centers’) - only for pyTree interface

Return type:

Identical to a

Example of use:

# - initScully (array) -
import Generator as G
import Converter as C
import Initiator as I

NI = 200; NJ = 200
HI = 1./(NI-1); HJ = 1./(NJ-1)
a = G.cart((0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
a = I.initScully(a, (0.5,0.5), -0.2, 0.05, 0.8, 0)
C.convertArrays2File([a], "out.plt")

# - initScully (pyTree) -
import Generator.PyTree as G
import Converter.PyTree as C
import Initiator.PyTree as I

NI = 200; NJ = 200
HI = 1./(NI-1); HJ = 1./(NJ-1)
a = G.cart((0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
a = I.initScully(a, (0.5,0.5), -0.2, 0.05, 0.8, 0, loc='centers')
C.convertPyTree2File(a, 'out.cgns')
Initiator.initYee(a, (x0, y0), Gamma=2., MInf=0.5, loc='nodes')

Initialization of conservative variables by a 2D Yee vortex at position (x0,y0), intensity Gamma and infinite Mach number MInf.

Exists also as in place version (_initYee) that modifies a and returns None.

Parameters:

  • a ([array, list of arrays] or [pyTree, base, zone, list of zones]) – Input data

  • Gamma (float) – Intensity of vortex

  • MInf (float) – Mach number

  • loc – field localisation (‘nodes’ or ‘centers’) - only for pyTree interface

Return type:

Identical to a

Example of use:

# - initYee (array) -
import Converter as C
import Generator as G
import Initiator as I

NI = 100; NJ = 100
HI = 50./(NI-1); HJ = 50./(NJ-1)
a = G.cart( (0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
a = I.initYee(a, position=(25.,25.), Gamma=2., MInf=0.8)
C.convertArrays2File([a], 'out.plt')

# - initYee (pyTree) -
import Converter.PyTree as C
import Generator.PyTree as G
import Initiator.PyTree as I

NI = 100; NJ = 100
HI = 50./(NI-1); HJ = 50./(NJ-1)
MachInf = 0.8

a = G.cart((0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
z = I.initYee(a, (3.,3.), 2., MachInf, loc='centers')
C.convertPyTree2File(z, 'out.cgns')
Initiator.initWissocq(a, (x0, y0), Gamma=0.07, MInf=0.5, loc='nodes')

Initialization of conservative variables by a 2D Wissocq vortex at position (x0,y0), intensity Gamma and infinite Mach number MInf.

Exists also as in place version (_initWissocq) that modifies a and returns None.

Parameters:

  • a ([array, list of arrays] or [pyTree, base, zone, list of zones]) – Input data

  • Gamma (float) – Intensity of vortex

  • MInf (float) – Mach number

  • loc – field localisation (‘nodes’ or ‘centers’) - only for pyTree interface

Return type:

Identical to a

Example of use:

# - initWissocq (array) -
import Generator as G
import Converter as C
import Initiator as I

NI = 200; NJ = 200
HI = 1./(NI-1); HJ = 1./(NJ-1)
a = G.cart((0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
a = I.initWissocq(a, (0.5,0.5), 0.07, 0.8)
C.convertArrays2File(a, "out.plt")

# - initWissocq (pyTree) -
import Generator.PyTree as G
import Converter.PyTree as C
import Initiator.PyTree as I

NI = 200; NJ = 200
HI = 1./(NI-1); HJ = 1./(NJ-1)
a = G.cart((0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
a = I.initWissocq(a, (0.5,0.5), 0.07, 0.8)
C.convertPyTree2File(a, "out.cgns")
Initiator.overlayField(a, b, MInf=0.5, loc='nodes')

Overlay the field of two solutions defined on the same grid (defined in a and b). Only density, velocity and energy stagnation density are overlaid. Both fields must use the same adimensioning, which corresponds to the same infinite Mach number MInf.

Exists also as in place version (_overlayField) that modifies a and returns None.

Parameters:

  • a ([array, list of arrays] or [pyTree, base, zone, list of zones]) – First input data

  • b ([array, list of arrays] or [pyTree, base, zone, list of zones]) – Second input data

  • MInf (float) – Mach number

  • loc – field localisation (‘nodes’ or ‘centers’) - only for pyTree interface

Return type:

Identical to a

Example of use:

# - overlayField (array) -
import Converter as C
import Generator as G
import Initiator as I

NI = 100; NJ = 100
HI = 50./(NI-1); HJ = 50./(NJ-1)
MachInf = 0.8

a = G.cart((0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
ac = I.initVisbal(a, (3.,3.), 2., MachInf)
ac2 = I.initVisbal(a, (20.,3.), 2., MachInf)
an = I.overlayField(ac, ac2, MachInf)
C.convertArrays2File([an], "out.plt")

# - overlayField (pyTree) -
import Converter.PyTree as C
import Generator.PyTree as G
import Initiator.PyTree as I

NI = 100; NJ = 100
HI = 50./(NI-1); HJ = 50./(NJ-1)
MachInf = 0.8
a = G.cart((0.,0.,0.), (HI,HJ,1.), (NI,NJ,2))
z1 = I.initVisbal(a, (3.,3.), 2., MachInf, loc='centers'); z1[0]='cart1'
z2 = I.initVisbal(a, (20.,3.), 2., MachInf, loc='centers'); z2[0]='cart2'
zn = I.overlayField(z1, z2, MachInf, loc='centers')
C.convertPyTree2File(zn, 'out.cgns')

Adimensioning

Initiator.Adim.adim1(MInf=0.5, alphaZ=0., alphaY=0., ReInf=1.e8, MutSMuInf=0.2, TurbLevelInf=1.e-4, Mtip=None)

Return a reference state corresponding to an adimensioning by density, sound speed and temperature. Returned state is adimensioned. When using this state, the mesh must also be adimensioned.

Parameters:

  • MInf (float) – Mach number

  • alphaZ (float) – Angle with respect to (0,Z) axe (in degrees)

  • alphaY (float) – Angle with respect to (0,Y) axe (in degrees)

  • ReInf (float) – Reynolds Number

  • MutSMuInf (float) – ratio of mut/mu (turbulence viscosity/molecular viscosity) at infinity

  • TurbLevelInf – turbulence level at infinity

  • Mtip (float or None) – if not None, used as speed definition for viscous and turbulent values

Returns:

[RoInf, RouInf, RovInf, RowInf, RoEInf, PInf, TInf, cvInf, MInf, ReInf, Cs, Gamma, RokInf, RoomegaInf, RonutildeInf, Mus, Cs, Ts, Pr]

Return type:

list

Example of use:

# - adim1 -
import Initiator.Adim as Adim
state = Adim.adim1(MInf=0.8, alphaZ=1., ReInf=1.e6); print(state)
#>> [1.0, 0.799878156125113, 0.01396192514982681, 0.0, 2.1057142857142863, 
#>> 0.7142857142857143, 1.0, 1.7857142857142863, 0.8, 1000000.0, 
#>> 0.3831337844872463, 1.4, 8e-09, 0.049999999999999996, 
#>> 1.6000000000000003e-07, 8.000000000000001e-07, 0.3831337844872463, 1.0, 0.70951]

Note

New in version 2.5

Initiator.Adim.adim2(MInf=0.5, alphaZ=0., alphaY=0., ReInf=1.e8, MutSMuInf=0.2, TurbLevelInf=1.e-4)

Return a reference state corresponding to an adimensioning by density, fluid velocity and temperature. Returned state is adimensioned. When using this state, the mesh must also be adimensioned.

Parameters:

  • MInf (float) – Mach number

  • alphaZ (float) – Angle with respect to (0,Z) axe (in degrees)

  • alphaY (float) – Angle with respect to (0,Y) axe (in degrees)

  • ReInf (float) – Reynolds Number

  • MutSMuInf (float) – ratio of mut/mu (turbulence viscosity/molecular viscosity) at infinity

  • TurbLevelInf – turbulence level at infinity

Return type:

[RoInf, RouInf, RovInf, RowInf, RoEInf, PInf, TInf, cvInf, MInf, ReInf, Cs, Gamma, RokInf, RoomegaInf, RonutildeInf, Mus, Cs, Ts, Pr]

Example of use:

# - adim2 -
import Initiator.Adim as Adim
state = Adim.adim2(MInf=0.8, alphaZ=1., ReInf=1.e6); print(state)
#>> [1.0, 0.9998476951563913, 0.01745240643728351, 0.0, 3.290178571428572, 
#>> 1.1160714285714286, 1.0, 2.790178571428572, 0.8, 1000000.0, 
#>> 0.3831337844872463, 1.4, 1e-08, 0.05, 2e-07, 1e-06, 0.3831337844872463, 
#>> 1.0, 0.70951]

Note

New in version 2.5

Initiator.Adim.adim3(MInf=0.5, alphaZ=0., alphaY=0., ReInf=1.e8, LInf=1., MutSMuInf=0.2, TurbLevelInf=1.e-4, Mtip=None)

Return a reference state corresponding to an adimensioning by density, sound speed and temperature. Returned state is adimensioned. When using this state, the mesh doesn’t need to be adimensioned and has a characteritic length of LInf.

Parameters:

  • MInf (float) – Mach number

  • alphaZ (float) – Angle with respect to (0,Z) axe (in degrees)

  • alphaY (float) – Angle with respect to (0,Y) axe (in degrees)

  • ReInf (float) – Reynolds Number

  • LInf (float) – Characteristic length of mesh (on which ReInf is based)

  • MutSMuInf (float) – ratio of mut/mu (turbulence viscosity/molecular viscosity) at infinity

  • TurbLevelInf – turbulence level at infinity

  • Mtip (float or None) – if not None, used as speed definition for viscous and turbulent values

Return type:

[RoInf, RouInf, RovInf, RowInf, RoEInf, PInf, TInf, cvInf, MInf, ReInf, Cs, Gamma, RokInf, RoomegaInf, RonutildeInf, Mus, Cs, Ts, Pr]

Example of use:

# - adim3 -
import Initiator.Adim as Adim
state = Adim.adim3(MInf=0.8, alphaZ=1., LInf=2.5, ReInf=1.e6); print(state)
#>> [1.0, 0.799878156125113, 0.01396192514982681, 0.0, 2.1057142857142863, 
#>> 0.7142857142857143, 1.0, 1.7857142857142863, 0.8, 1000000.0, 
#>> 0.3831337844872463, 1.4, 8e-09, 0.02, 4e-07, 2e-06, 0.3831337844872463, 
#>> 1.0, 0.70951]

Note

New in version 2.5

Initiator.Adim.dim1(UInf=2.7777, TInf=298.15, PInf=101325., LInf=1., alphaZ=0., alphaY=0., MutSMuInf=0.2, TurbLevelInf=1.e-4, Mtip=None)

Return a dimensioned reference state corresponding to dry air, considered as a perfect gaz. Returned a dimensioned state (USI).

Parameters:

  • UInf (float) – Fluid velocity in m/s

  • TInf (float) – Temperature in K (0 degree=273.15K)

  • PInf (float) – Pressure in Pa

  • LInf (float) – Reference length (m). Usefull to compute Reynolds.

  • MutSMuInf (float) – ratio of mut/mu (turbulence viscosity/molecular viscosity) at infinity

  • TurbLevelInf – turbulence level at infinity

  • Mtip (float or None) – if not None, used as speed definition for viscous and turbulent values

Return type:

[RoInf, RouInf, RovInf, RowInf, RoEInf, PInf, TInf, cvInf, MInf, ReInf, Cs, Gamma, RokInf, RoomegaInf, RonutildeInf, Mus, Cs, Ts, Pr]

Example of use:

# - dim1 -
import Initiator.Adim as Adim
state = Adim.dim1(UInf=2.8, TInf=298., PInf=101325, LInf=12., alphaZ=1.); print(state)
#>> [1.1845087092749074, 3.3161192480113266, 0.05788307678374978, 0.0, 
#>> 253317.14327414043, 101325, 298.0, 717.6325, 0.00809104909572454, 
#>> 2167112.2969719185, 110.4, 1.4, 3.316624385969741e-08, 0.009029634570716328, 
#>> 3.673043864616362e-06, 1.78938e-05, 110.4, 288.15, 0.7084595175093612]

Note

New in version 2.5

Initiator.Adim.dim2(UInf=2.7777, TInf=298.15, RoInf=1.225, LInf=1., alphaZ=0., alphaY=0., MutSMuInf=0.2, TurbLevelInf=1.e-4, Mtip=None)

Return a dimensioned reference state corresponding to dry air, considered as a perfect gaz. Only the input is different from dim1. Returned a dimensioned state (USI).

Parameters:

  • UInf (float) – Fluid velocity in m/s

  • TInf (float) – Temperature in K (0 degree=273.15K)

  • RoInf (float) – Input density (kg/m3)

  • LInf (float) – Reference length (m). Usefull to compute Reynolds.

  • MutSMuInf (float) – ratio of mut/mu (turbulence viscosity/molecular viscosity) at infinity

  • TurbLevelInf – turbulence level at infinity

  • Mtip (float or None) – if not None, used as speed definition for viscous and turbulent values

Return type:

[RoInf, RouInf, RovInf, RowInf, RoEInf, PInf, TInf, cvInf, MInf, ReInf, Cs, Gamma, RokInf, RoomegaInf, RonutildeInf, Mus, Cs, Ts, Pr]

Example of use:

# - dim2 -
import Initiator.Adim as Adim
state = Adim.dim2(UInf=2.8, TInf=298., RoInf=1.2, LInf=12., alphaZ=1.); print(state)
#>> [1.2, 3.3594882557254744, 0.058640085629272594, 0.0, 256630.08600000004, 
#>> 102650.1528, 298.0, 717.6325000000002, 0.00809104909572454, 
#>> 2195454.314521849, 110.4, 1.4, 3.3599999999999996e-08, 0.009147726310507706, 
#>> 3.673043864616362e-06, 1.78938e-05, 110.4, 288.15, 0.7084595175093613]

Note

New in version 2.5

Initiator.Adim.dim3(UInf=2.7777, PInf=101325., RoInf=1.225, LInf=1., alphaZ=0., alphaY=0., MutSMuInf=0.2, TurbLevelInf=1.e-4, Mtip=None)

Return a dimensioned reference state corresponding to dry air, considered as a perfect gaz. Only the input is different from dim1. Returned a dimensioned state (USI).

Parameters:

  • UInf (float) – Fluid velocity in m/s

  • PInf (float) – Pressure in Pa

  • RoInf (float) – Input density (kg/m3)

  • LInf (float) – Reference length (m). Usefull to compute Reynolds.

  • MutSMuInf (float) – ratio of mut/mu (turbulence viscosity/molecular viscosity) at infinity

  • TurbLevelInf – turbulence level at infinity

  • Mtip (float or None) – if not None, used as speed definition for viscous and turbulent values

Return type:

[RoInf, RouInf, RovInf, RowInf, RoEInf, PInf, TInf, cvInf, MInf, ReInf, Cs, Gamma, RokInf, RoomegaInf, RonutildeInf, Mus, Cs, Ts, Pr]

Example of use:

# - dim3 -
import Initiator.Adim as Adim
state = Adim.dim3(UInf=2.8, PInf=101325., RoInf=1.2, LInf=12., alphaZ=1.); print(state)
#>> [1.1999999999999997, 3.3594882557254735, 0.05864008562927258, 0.0, 
#>> 253317.20400000006, 101325.0, 294.152996136602, 717.6325000000002, 
#>> 0.0081437855769486, 2217576.314799729, 110.4, 1.4, 3.359999999999999e-08, 
#>> 0.009239901311665535, 3.6364024751627385e-06, 1.78938e-05, 110.4, 
#>> 288.15, 0.7094696135544664]

Note

New in version 2.5

Mesh size

Initiator.MeshSize.meshSize(UInf, RoInf, ReInf, LInf, esurc=0.012, yplus=1., algo='Turbulent'):

Return the height of the first wall mesh cell that must be set to match a certain y+.

Parameters:

  • UInf (float) – Inflow reference speed

  • RoInf (float) – Inflow reference density

  • ReInf (float) – Inflow reference Reynolds

  • LInf (float) – Reference length for Reynolds

  • esurc – profile thickness over chord (used only in Corr algorithms)

  • yplus (float) – target y+ to match

  • algo (string) – type of algorithm in ‘Turbulent’, ‘TurbulentCorr’, ‘LaminarCorr’

Example of use:

# - meshSize (pyTree) -
import Initiator.PyTree as I

hp = I.meshSize(UInf=1., RoInf=1.223, ReInf=6000, LInf=1., yplus=1, algo='Turbulent')
print(hp)

Note

New in version 3.4

Index