# Ityp = 0

Block Format Keyword This law enables to model a gas inlet condition by providing data from stagnation point. Gas is supposed to be a perfect gas.

## Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/MAT/LAW11/mat_ID/unit_ID or /MAT/BOUND/mat_ID/unit_ID
mat_title
${\rho }_{i}^{\mathit{stagnation}}$ ${\rho }_{0}^{\mathit{stagnation}}$
Ityp   Psh FscaleT
Ityp = 0 - Gas Inlet (from stagnation point data)
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
node_IDV   C1     Cd
$\mathit{fct}_{\mathit{ID}}_{\rho }$
fct_IDp   ${P}_{0}^{\mathit{stagnation}}$
Blank Format
Blank Format
fct_IDT fct_IDQ

## Definitions

Field Contents SI Unit Example
mat_ID Material identifier.

(Integer, maximum 10 digits)

unit_ID Unit Identifier.

(Integer, maximum 10 digits)

mat_title Material title.

(Character, maximum 100 characters)

${\rho }_{i}^{\mathit{stagnation}}$ Initial stagnation density. 3

(Real)

$\left[\frac{\text{kg}}{{\text{m}}^{\text{3}}}\right]$
${\rho }_{0}^{\mathit{stagnation}}$ Reference density used in E.O.S (equation of state).

Default ${\rho }_{0}^{\mathit{stagnation}}={\rho }_{i}^{\mathit{stagnation}}$ (Real)

$\left[\frac{\text{kg}}{{\text{m}}^{\text{3}}}\right]$
Ityp Boundary condition type. 1
= 0
Gas inlet (from stagnation point data)
= 1
Liquid inlet (from stagnation point data)
= 2
General inlet/outlet
= 3
Non-reflecting boundary

(Integer)

Psh Pressure shift. 2

(Real)

$\left[\text{Pa}\right]$
FscaleT Time scale factor. 3

(Real)

$\left[\text{s}\right]$
node_IDV Node identifier for velocity computation. 4
= 0
${v}_{\mathit{in}}=\underset{\mathit{nod}e\text{\hspace{0.17em}}\epsilon \text{\hspace{0.17em}}\mathit{face}}{\mathit{min}}\text{\hspace{0.17em}}\text{\hspace{0.17em}}{\stackrel{\to }{v}}_{node}\cdot \stackrel{\to }{n}$
> 0
${v}_{\mathit{in}}=‖{v}_{\mathit{node}_\mathit{ID}}‖$

(Integer)

$\gamma$ Perfect gas constant.

(Real)

Cd Discharge coefficient. 5

(Real)

fct_ID $\rho$ Function ${f}_{\rho }\left(t\right)$ identifier for stagnation density. 3
= 0
${\rho }^{\mathit{stagnation}}\left(t\right)={\rho }_{i}^{\mathit{stagnation}}$
> 0
${\rho }^{\mathit{stagnation}}\left(t\right)={\rho }_{i}^{\mathit{stagnation}}\cdot {f}_{\rho }\left(t\right)$

(Integer)

fct_IDp Function ${f}_{P}\left(t\right)$ identifier for stagnation pressure. 3
= 0
${P}^{\mathit{stagnation}}\left(t\right)={P}_{0}^{\mathit{stagnation}}$
> 0
${P}^{\mathit{stagnation}}\left(t\right)={P}_{0}^{\mathit{stagnation}}\cdot {f}_{P}\left(t\right)$

(Integer)

${P}_{0}^{\mathit{stagnation}}$ Initial stagnation pressure. 3

(Real)

$\left[\text{Pa}\right]$
fct_IDT Function ${f}_{T}\left(t\right)$ identifier for inlet temperature. 3 6
= 0
$T={T}_{\mathit{adjacent}}$
= n
$T={T}_{0}\cdot {f}_{T}\left(t\right)$

(Integer)

fct_IDQ Function ${f}_{Q}\left(t\right)$ identifier for inlet heat flux. 3 6
= 0
No imposed flux
= n
$Q={f}_{Q}\left(t\right)$

(Integer)

1. Provided gas state from stagnation point $\left({\rho }_{\mathit{stagnation},\text{\hspace{0.17em}}}{P}_{\mathit{stagnation}}\right)$ is used to compute inlet gas state.
$\begin{array}{l}{\rho }_{\mathit{in}}={\rho }_{\mathit{stagnation}}\cdot {\left[1-\frac{\gamma -1}{2\gamma }\cdot \frac{{\rho }_{\mathit{stagnation}}}{{P}_{\mathit{stagnation}}}\cdot \left(1+{C}_{d}\right)\cdot {v}_{\mathit{in}}^{2}\right]}^{\frac{1}{\gamma -1}}\\ {P}_{\mathit{in}}={P}_{\mathit{stagnation}}{\left(\frac{{\rho }_{\mathit{in}}}{{\rho }_{\mathit{stagnation}}}\right)}^{\gamma }\\ {\left(\rho e\right)}_{\mathit{in}}=\frac{{P}_{\mathit{in}}}{\gamma -1}\end{array}$
2. The Psh parameter enables shifting the output pressure which also becomes P-Psh. If using Psh=P(t=0), the output pressure will be $\text{Δ}P$ , with an initial value of 0.0.
3. If no function is defined, then related quantity $\left({P}_{\mathit{stagnation}},\text{\hspace{0.17em}}{\rho }_{\mathit{stagnation}},\text{\hspace{0.17em}}T,\text{\hspace{0.17em}}\mathit{or}\text{\hspace{0.17em}}Q\right)$ remains constant and set to its initial value. However, all input quantities $\left({P}_{\mathit{stagnation}},\text{\hspace{0.17em}}{\rho }_{\mathit{stagnation}},\text{\hspace{0.17em}}T,\text{\hspace{0.17em}}\mathit{and}\text{\hspace{0.17em}}Q\right)$ can be defined as time dependent function using provided function identifiers. Abscissa functions can also be scaled using FscaleT parameter which leads to use f (Fscalet * t) instead of f(t).
4. Inlet velocity ${v}_{\mathit{in}}$ is used in Bernoulli theory.
6. With thermal modeling, all thermal data ( ${T}_{0},\text{\hspace{0.17em}}{\rho }_{0}{C}_{P}$ , ...) can be defined with /HEAT/MAT.