/EBCS
Block Format Keyword Describes the elementary boundary condition sets.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
/EBCS/type/ebcs_ID/unit_ID | |||||||||
ebcs_title |
Type: GRADP0, PRES, VALVIN or VALVOUT
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
surf_ID | |||||||||
C | |||||||||
fct_IDpr | Fscalepr | ||||||||
fct_IDrho | Fscalerho | ||||||||
fct_IDen | Fscaleen | ||||||||
lc | r1 | r2 |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
surf_ID | |||||||||
C | |||||||||
fct_IDvx | Fscalevx | ||||||||
fct_IDvy | Fscalevy | ||||||||
fct_IDvz | Fscalevz | ||||||||
fct_IDpr | Fscalepr | ||||||||
fct_IDrho | Fscalerho | ||||||||
fct_IDen | Fscaleen | ||||||||
lc | r1 | r2 |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
surf_ID | |||||||||
C | |||||||||
fct_IDvim | Fscalevim | ||||||||
fct_IDrho | Fscalerho | ||||||||
fct_IDen | Fscaleen | ||||||||
lc | r1 | r2 |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
surf_ID | |||||||||
Rho | C |
Definitions
Field | Contents | SI Unit Example |
---|---|---|
type | Elementary boundary
condition keyword. (see EBCS Type for available keywords) |
|
ebcs_ID | Elementary boundary
condition identifier. (Integer, maximum 10 digits) |
|
unit_ID | Unit Identifier (Integer, maximum 10 digits) |
|
ebcs_title | Elementary boundary
condition title. (Character, maximum 100 characters) |
|
surf_ID | Surface
identifier. (Integer) |
|
C | Speed of sound. Default = 0 (Real) |
|
fct_IDpr | Function
identifier for pressure.
(Integer) |
|
Fscalepr | Pressure scale
factor. Default = 0 (Real) |
|
fct_IDrho | Function
identifier for density.
(Integer) |
|
Fscalerho | Density scale
factor. Default = 0 (Real) |
|
fct_IDen | Function
identifier for energy.
(Integer) |
|
Fscaleen | Energy scale
factor. Default = 0 (Real) |
|
Characteristic
length. Default = 0 (Real) |
||
r1 | Linear resistance. 6 Default = 0 (Real) |
|
r2 | Quadratic resistance.
6 Default = 0 (Real) |
|
fct_IDvx | Function
identifier for X velocity.
(Integer) |
|
Fscalevx | X velocity scale
factor. Default = 0 (Real) |
|
fct_IDvy | Function
identifier for Y velocity.
(Integer) |
|
Fscalevy | Y velocity scale
factor. Default = 0 (Real) |
|
fct_IDvz | Function
identifier for Z velocity.
(Integer) |
|
Fscalevz | Z velocity scale
factor. Default = 0 (Real) |
|
fct_IDvim | Function
identifier for imposed velocity.
(Integer) |
|
Fscalevim | Imposed
velocity. Default = 0 (Real) |
|
Rho | Initial density. Default = 0 (Real) |
EBCS Type
Type | Keyword | Description |
---|---|---|
0 | GRADP0 | Zero pressure gradient. Is not allowed for SPMD parallel version. |
1 | PRES | Imposed density and pressure |
2 | VALVIN | Inlet valve (Imposed density and pressure) |
3 | VALVOUT | Outlet valve (Imposed density and pressure) |
4 | VEL | Imposed velocity |
5 | NORMV | Imposed normal velocity |
6 | INIP | Initial pressure |
7 | INIV | Initial velocity |
Comments
- Input is general, no prior assumptions are enforced! You must verify that the elementary boundaries are consistent with general assumptions of ALE (equation closure).
- It is not advised to use the Hydrodynamic Bi-material Liquid Gas Law (/MAT/LAW37 (BIPHAS)) with the elementary boundary conditions.
- Density, pressure, energy are imposed according to a scale factor and a time function. If the function number is 0, the imposed density, pressure and energy are used.
- All EBCS which type is less tha four or
equal to six are non-reflective frontiers (NRF), using:
(1) Pressure in the far field is imposed with a function of time. The transient pressure is derived from , the local velocity field V and the normal of the outlet facet.
Where, is the characteristic length, to compute cutoff frequency as:(2) - In order to impose a positive velocity fct_IDvim (for instance 15 m/s), you must input -fct_IDvim (for instance -15 m/s).
- A resistance pressure is computed and
added to the current pressure.
(3) It aims at modeling the friction loss due to the valves.