/SPH/INOUT

Block Format Keyword Describes the SPH inlet/outlet conditions.

Format

(1)	(2)	(3)	(4)	(6)	(7)	(8)	(9)
/SPH/INOUT/`condition_ID`
`condition_name`
`Ityp`	`part_ID`	`surf_ID`	`Dist`	`node_ID`₁	`node_ID`₂	`node_ID`₃	`F`_cut

Input read only if surf_ID = 0, node_ID₁ = 0, node_ID₂ = 0 and node_ID₃ = 0 22, 23, 24

(1)	(3)	(5)
`X`_M	`Y`_M	`Z`_M
`X`_M1	`Y`_M1	`Z`_M1
`X`_M2	`Y`_M2	`Z`_M2

Ityp =1 - General Inlet 12 through 16

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
`fct_ID`_r	`Fscale`_r					`fct_ID`_E	`Fscale`_E
`fct_ID`_Vn

Ityp =2 - General Outlet 17, 18, 19

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
			`fct_ID`_P	`Fscale`_P
Blank Format

Ityp =3 - Non-Reflective Frontiers (NRF) 19, 20, 21

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
			`fct_ID`_P	`Fscale`_P		$l_{c}$
Blank Format

Definitions

Field	Contents	SI Unit Example
`condition_ID`	Inlet/Outlet condition identifier (Integer, maximum 10 digits)
`condition_name`	Inlet/Outlet condition name (Character, maximum 100 characters)
`Ityp`	Condition type 22 24 =1 General inlet. the surface must be meshed, only a surface Id can be input. =2 General outlet =3 Non-reflective frontiers (NRF) =4 Control section. Control tool, only used for mass flux measurement. (Integer)
`part_ID`	Part identifier is used in order to define the SPH particles concerned by the condition. (Integer)
`surf_ID`	Surface identifier (Integer)
`Dist`	Distance from the surface for particle control (Real)	$[m]$
`node_ID`₁	Optional ID of node 1 (`Itype` ≠ 1) (Integer)
`node_ID`₂	Optional ID of node 2 (`Itype` ≠ 1) (Integer)
`node_ID`₃	Optional ID of node 3 (`Itype` ≠ 1) (Integer)
`Fcut`	Optional Cutoff frequency (`Itype` ≠ 1) Default = 0 (Real)
`X`_M	Optional X coordinate of M (`Itype` ≠ 1) (Real)
`Y`_M	Optional Y coordinate of M (`Itype` ≠ 1) (Real)
`Z`_M	Optional Z coordinate of M (`Itype` ≠ 1) (Real)
`X`_M1	Optional X coordinate of M1 (`Itype` ≠ 1) (Real)
`Y`_M1	Optional Y coordinate of M1 (`Itype` ≠ 1) (Real)
`Z`_M1	Optional Z coordinate of M1 (`Itype` ≠ 1) (Real)
`X`_M2	Optional X coordinate of M2 (`Itype` ≠ 1) (Real)
`Y`_M2	Optional Y coordinate of M2 (`Itype` ≠ 1) (Real)
`Z`_M2	Optional Z coordinate of M2 (`Itype` ≠ 1) (Real)
`fct_ID`_r	Function `f`_r`(t)` identifier for density (Integer)
`Fscale`_r	Density scale factor Default = 0.0 (Real)	$[\frac{kg}{m^{3}}]$
`fct_ID`_E	Function `f`_E`(t)` identifier for energy (Integer)
`Fscale`_E	Energy per volume unit scale factor Default = 0.0 (Real)	$[\frac{J}{m^{3}}]$
`fct_ID`_Vn	Function `f`_Vn`(t)` identifier for velocity in normal direction (Integer)
`fct_ID`_P	Function `f`_P`(t)` identifier for pressure (Integer)
`Fscale`_P	Pressure scale factor Default = 1.0 (Real)	$[Pa]$
$l_{c}$	Characteristic length 21 (Real)	$[m]$

Comments

The surface segments must be orientated so that their normal vectors point towards the interior of the domain.
The surface must be fixed.
In case of an inlet condition, the condition enters particles belonging to its related part, so long as inactive particles are available for this part. The behavior of the particles belonging to the part which is related to the condition is set with respect to the condition characteristics for all particles lying on the positive side of the surface, within the distance Dist from the inlet surface.
In case of an outlet condition, the behavior of the particles belonging to the part which is related to the condition is set with respect to the condition characteristics for all particles lying on the negative side of the surface, within the distance Dist from the outlet surface. Such a particle is deactivated if it does not interact with any non-outgoing particle.
A particle deactivated by an outlet condition can be re-used by an inlet condition acting on the same part for incoming.
If using outlets, order = -1 is recommended in the relative SPH property.
In case of an outlet, the initial net must be provided up to the distance of 2h down to the outlet surface (where h is the smoothing length into the relative property).
In case of inlet or outlet, the distance must be large enough, in order to control incoming or outgoing particles within at least a distance of 2h.

Figure 1. Inlet/Outlet Conditions Organization Overview
The domains defined by two inlet/outlet surfaces and distances must not overlap.
It is recommended for both, inlets and outlets, particles to be initially defined and controlled within more than twice the smoothing length of the particles.
Inlet/outlet conditions option is allowed for SPMD parallel version. Parallel Arithmetic (same numerical results obtained whatever the number of processors) is not guaranteed for inlet conditions.
Each incoming particle belonging to the part which is related to the condition gets the same mass m_p (defined into the geometrical property which is attached to the part).
A particle belonging to this part is entered at the center of a surface segment each time t such that:(1)
$m_{p} \geq \int_{t_{l a s t}}^{t} ρ (t) \cdot S_{i} \cdot v (t) d t$

Where,

S_i

Area of the segment

$ρ (t)$ and $v (t)$

The density and velocity of the incoming matier (Lines 2 and 3)

t_last

Time at last incoming through this segment

It is recommended to use a regular surface mesh.
If no inactive particle belonging to this part is available for incoming, the program stops and you should provide a larger set of inactive particles for this part.
If a particle belonging to the part which is related to the condition lies on the positive side of the surface within the Dist, its velocity is set with respect to the data given at Line 5.
If fct_ID_r = 0, density of the incoming particles is set to: (2)
$ρ_{a} = F s c a l e_{r}$

else(3)
$ρ_{a} = F s c a l e_{_{r}} \cdot f_{r} (t)$
If fct_ID_E = 0, energy per volume unit of the incoming particles is set to $E_{a} = F s c a l e_{E}$ , else $E_{a} = F s c a l e_{E} \cdot f_{E} (t)$ .
If a particle belonging to the part which is related to the condition lies on the negative side of the surface within the Dist, its internal pressure is set with respect to the data given at Line 6.
If the particle does not interact with any non-outgoing particle, the particle is deactivated.
If fct_ID_P = 0, internal pressure of the outgoing particles is set to the internal pressure of the closest particle lying above the outlet surface, else it is set to $F s c a l e_{P} \cdot f_{P} (t)$ .
If a particle belonging to the part which is related to the condition lies on the negative side of the surface within the Dist, its internal pressure is set with respect to the equation:
(4)
$\frac{\partial P}{\partial t} = ρ c \frac{\partial V_{n}}{\partial t} + c \frac{(P_{\infty} - P)}{2 l_{c}}$
If fct_ID_P = 0, pressure in the far field $P_{\infty}$ is set to Fscale_P, else it is set to Fscale_P f_P(t).
$l_{c}$ is the characteristic length, it allows to compute cutoff frequency $f_{c}$ as:
(5)
$f_{c} = \frac{c}{4 \cdot π \cdot l_{c}}$
If Itype = 2, 3 or 4, the surface can be defined by a meshed surface (surf_ID > 0), by 3 nodes (node_ID₁ > 0, node_ID₂ > 0 and node_ID₃ > 0) or by the coordinates of 3 nodes (M, M1 and M2).

Figure 2.
If Itype = 2, 3 or 4 and if the surface is defined by 3 coordinates, then the surface will be fixed. If the surface is defined by a surface ID or by 3 nodes, the surface will move according to the displacement of the shell elements or nodes.
If Itype = 2, 3 or 4, a computation of the total mass crossing the surface is automatically performed and can be plotted using /TH/SPH_FLOW.