Block Format Keyword Describes the ideal gas equation of state
.
Format
(1) |
(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
/EOS/IDEAL-GAS/mat_ID/unit_ID or /EOS/IDEAL-GAS-VE/mat_ID/unit_ID |
eos_title |
|
P0 |
Psh |
T0 |
|
Definition
Field |
Contents |
SI Unit
Example |
mat_ID |
Material
identifier. (Integer, maximum 10 digits)
|
|
unit_ID |
Unit Identifier. (Integer, maximum 10 digits)
|
|
eos_title |
EOS
title. (Character, maximum 100 characters)
|
|
|
Heat capacity ratio
. (Real)
|
|
P0 |
Initial
pressure. (Real)
|
|
Psh |
Pressure
shift. (Real)
|
|
T0 |
Initial
temperature. (Real)
|
|
Example (Air)
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/1
unit for mat
g mm ms
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/MAT/HYDRO/7/1
AIR
# RHO_I RHO_0
1.22e-6 0
# Knu Pmin
1.5E-2 0
/EOS/IDEAL-GAS/7/1
EoS for Air at atmospheric pressure
# GAMMA P0 PSH T0
1.4 0.10 0 300.0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#enddata
Comments
- Ideal-gas thermal EOS is:(1)
Where,
-
- Specific volume
-
- Specific gas constant
-
- Temperature
Previous form of
can be written in the
form.
Where,
(2)
(3)
(4)
with
(5)
Where,
and
are constant parameters.
Consequently,
the same equation of state can be built using
/EOS/IDEAL-GAS-VT (Volume Temperature) defining the
special case of a constant function:
(6)
- Some characteristics of this equation of state:
- Ideal Gas
-
-
-
-
- Sounce speed
-
-
-
- For this equation of state,
,
and
are constant parameters.
In other cases,
/EOS/IDEAL-GAS-VT (Volume Temperature) must be
used.
The heat capacity
is computed from the initial
data:
(7)
This parameter enables the calculation of the gas
temperature since
(8)
Where,
-
- Specific energy by mass
- Equations of state are used by
Radioss to compute the hydrodynamic pressure and are
compatible with the material laws:
- /MAT/LAW3 (HYDPLA)
- /MAT/LAW4 (HYD_JCOOK)
- /MAT/LAW6 (HYDRO or HYD_VISC)
- /MAT/LAW10 (DPRAG1)
- /MAT/LAW12 (3D_COMP)
- /MAT/LAW49 (STEINB)
- /MAT/LAW102 (DPRAG2)
- /MAT/LAW103 (HENSEL-SPITTEL)