/MONVOL/LFLUID

Block Format Keyword Describes the pressure of a linear fluid using a monitored volume.

Format

(1)	(2)	(3)	(5)
/MONVOL/LFLUID/`monvol_ID`/`unit_ID`
`monvol_title`
`surf_ID`_ex
`Ascale`_t		`Ascale`_P
$ρ$
`fct_K`	`fct_Mt`_in	`Fscale_K`	`Fscale_Mt`_in
`fct_Mt`_out	`fct_Mp`_out	`Fscale_Mt`_out	`Fscale_Mp`_out
`fct_P`_add	`fct_P`_max	`Fscale_P`_add	`Fscale_P`_max

Definitions

Field	Contents	SI Unit Example
`monvol_ID`	Monitored volume identifier (Integer, maximum 10 digits)
`unit_ID`	Unit Identifier (Integer, maximum 10 digits)
`monvol_title`	Monitored volume title (Character, maximum 100 characters)
`surf_ID`_ex	External surface identifier. (Integer)
`Ascale`_t	Abscissa scale factor for time based functions. Default = 1.0 (Real)	$[s]$
`Ascale`_P	Abscissa scale factor for pressure based functions. Default = 1.0 (Real)	$[Pa]$
$ρ$	Fluid density. (Real)	$[\frac{kg}{m^{3}}]$
`fct_K`	Load curve identifier for bulk modulus $K (t)$ . (Integer)
`Fscale_K`	Load curve scale factor for bulk modulus or constant bulk modulus. 7	$[Pa]$
`fct_Mt`_in	Load curve identifier for input mass flow rate ${\dot{m}}_{i n} (t)$ . (Integer)
`Fscale_Mt`_in	Load curve scale factor for input mass flow rate or constant input mass flow rate. 7	$[\frac{kg}{s}]$
`fct_Mt`_out	Load curve identifier for mass flow rate ${\dot{m}}_{o u t} (t)$ . (Integer)
`Fscale_Mt`_out	Load curve scale factor for output mass flow rate or constant output mass flow rate. 7	$[\frac{kg}{s}]$
`fct_Mp`_out	Load curve identifier for output mass flow rate ${\dot{m}}_{o u t} (p)$ as a function of pressure. (Integer)
`Fscale_Mp`_out	Load curve scale factor for output mass flow rate or constant output mass flow rate. 7	$[\frac{kg}{s}]$
`fct_P`_add	Load curve identifier for additional pressure $P_{a d d} (t)$ . (Integer)
`Fscale_P`_add	Load curve scale factor for additional pressure or constant additional pressure. 7	$[\frac{kg}{s}]$
`fct_P`_max	Load curve identifier for maximum pressure $P_{\max} (t)$ . (Integer)
`Fscale_P`_max	Load curve scale factor for maximum pressure or constant maximum pressure. 7	$[Pa]$

Comments

The pressure inside the monitored volume is defined as:(1)
$P (t) = K (t) \cdot \ln (\frac{V_{0} (t)}{V (t)}) + P_{a d d} (t)$
surf_ID_ex must be defined using segments associated with 4- or 3-nodes shell elements (possibly void elements) and not with /SURF/SEG.
The shell elements that define the surface of the monitored volume should not be deleted or eroded.
The volume must be closed and the normals must be oriented outwards.
Abscissa scale factors are used to transform abscissa units in airbag functions, for example:(2)
$f (t) = f_{} (\frac{t}{A s c a l e_{t}})$

Where, $t$ is the time.(3)
$f (p) = f (\frac{p}{A s c a l e_{P}})$

Where, $p$ is the pressure.
Fluid mass is computed as:(4)
$m (t) = m (0) + \int_{0}^{t} {\dot{m}}_{i n} (t) d t - \int_{0}^{t} {\dot{m}}_{o u t}^{} (t) d t - \int_{0}^{t} {\dot{m}}_{o u t}^{} (p) d t$
If the load curve identifier fct_ is defined, then the Fscale_ is a scale factor for the load curve with a default value = 1.0:
$K (t) = F s c a l e_K \cdot f c t_K$

If the load curve identifier fct_ is not defined, then Fscale_ defines a constant input value:

$K (t) = F s c a l e_K$