/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

Definition

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 the case of an inlet condition, the condition enters particles belonging to its related part, as long as inactive particles are available for this part. The behavior of the particles belonging to the part which is associated with the condition is set with respect to the condition characteristics for all particles located on the positive side of the surface, within the distance Dist from the inlet surface.
In the case of an outlet condition, the behavior of the particles belonging to the part associated with the condition is set with respect to the condition characteristics for all particles located 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 the case of an outlet, the initial mesh must be created at a distance of up to 2h from the outlet surface (where h is the smoothing length in the relative property).
In the 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 Conditions Organization Overview

Figure 2. Outlet Conditions Organization Overview
The domains defined by two inlet/outlet surfaces and distances must not overlap.
It is recommended to initially define and control the particles at both inlets and outlets to more than twice the particle smoothing length.
The inlet/outlet conditions option is allowed for the SPMD parallel version. However, parallel arithmetic (the same numerical results are obtained regardless of the number of processors) is not guaranteed for inlet conditions.
Each incoming particle belonging to the part related to the condition receives the same mass m_p (defined in the geometric property attached to the part).
A particle belonging to this part is entered in the center of a surface segment at 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 inactive particles belonging to this part are not 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 related to the condition is located on the positive side of the surface within the Dist, its velocity is set with respect to the data specified in Line 5.
If fct_ID_r = 0, the density of the incoming particles is set to: (2)
$ρ_{a} = F s c a l e_{r}$

otherwise,(3)
$ρ_{a} = F s c a l e_{_{r}} \cdot f_{r} (t)$
If fct_ID_E = 0, the energy per volume unit of the incoming particles is set to $E_{a} = F s c a l e_{E}$ ,
otherwise,(4)
$E_{a} = F s c a l e_{E} \cdot f_{E} (t)$
If a particle belonging to the part which is related to the condition is located on the negative side of the surface within the Dist, its internal pressure is set with respect to the data specified in Line 6.
If the particle does not interact with any non-outgoing particle, the particle is deactivated.
If fct_ID_P = 0, the internal pressure of the outgoing particles is set to the internal pressure of the closest particle is located above the outlet surface,
otherwise it is set to(5)
$F s c a l e_{P} \cdot f_{P} (t)$
If a particle belonging to the part related to the condition is located on the negative side of the surface within the Dist, its internal pressure is set with respect to the equation:
(6)
$\frac{\partial P}{\partial t} = ρ c \frac{\partial V_{n}}{\partial t} + c \frac{(P_{\infty} - P)}{2 l_{c}}$
If fct_ID_P = 0, the pressure in the far field $P_{\infty}$ is set to Fscale_P,
otherwise it is set to Fscale_P f_P(t).
$l_{c}$ is the characteristic length, which allows to compute cutoff frequency $f_{c}$ as:
(7)
$f_{c} = \frac{c}{4 \cdot π \cdot l_{c}}$
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 3.
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.