/INIGRAV

Block Format Keyword Defines initial state from hydrostatic pressure due to gravity loading.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/INIGRAV/inigrav_ID/unit_ID
inigrav_title
grpart_ID surf_ID grav_ID              
Pref Bx By Bz    

Definitions

Field Contents SI Unit Example
inigrav_ID Initial gravity loading identifier

(Integer, maximum 10 digits)

 
unit_ID Optional unit identifier

(Integer, maximum 10 digits)

 
inigrav_title Initial gravity loading title.

(Character, maximum 100 characters)

 
grpart_ID Group of part identified. If non defined (0), initial state is applied on all solid PARTs.

Default = 0 (Integer)

 
surf_ID (Optional) Free surface identifier.

If not defined, basis point is read.

(Integer)

 
grav_ID (Mandatory) Gravity card identifier used.

(Integer)

 
Pref Reference pressure on the reference surface.

(Real)

[ Pa ]
Bx Basis point X-coordinate (used only if surf_ID=0)

(Real)

[ m ]
By Basis point Y-coordinate (used only if surf_ID=0)

(Real)

[ m ]
Bz Basis point Z-coordinate (used only if surf_ID=0)

(Real)

[ m ]

Example (Water Hydrostatic Pressure)

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/1
unit for load
#              MUNIT               LUNIT               TUNIT
                   g                  mm                  ms
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/INIGRAV/1/1
hydrostatique pressure - “ sea level : {Z=0} where Pref=0.101325 MPa
#GRPART_ID   SURF_ID   GRAV_ID    
         0         0         1  
#               Pref                  Bx                  By                  Bz          
            0.101325                   0                   0                   0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/GRAV/1/1
Terrestrial gravity field
#funct_IDT       DIR   skew_ID sensor_ID  grnod_ID                      Ascale_x            Fscale_Y
         2         Z         0         0         5                             0            -0.00981
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/2
unity
#                  X                   Y
                   0                 1.0                                                            
             1000000                 1.0                                                            
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#enddata

Comments

  1. Gravity value and direction are read from /GRAV card, then grav_ID value is mandatory.
  2. Surface is defined by basis point B=(Bx, By, Bz) and normal vector gn MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqGqFfpeea0xe9vq=Jb9 vqpeea0xd9q8qiYRWxGi6xij=hbba9q8aq0=yq=He9q8qiLsFr0=vr 0=vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaWGNbGaey yXICTaaCOBaaaa@3B95@ unless a surface identifier surf_ID is provided. surf_ID is currently only compatible with /SURF/PLANE option in 2018.0 release.
  3. Pref is the reference pressure which is measured on reference surface. Usually it is pressure at sea level. Above the surface pressure is decreasing, below it is increasing using. The pressure change depends on the signed distance from the reference surface:
    (1)
    Δ P 0 = ρ 0 | g | d i s t MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqGqFfpeea0xe9vq=Jb9 vqpeea0xd9q8qiYRWxGi6xij=hbba9q8aq0=yq=He9q8qiLsFr0=vr 0=vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacqGHuoarca WGqbWaaSbaaSqaaiaaicdaaeqaaOGaeyypa0JaeqyWdi3aaSbaaSqa aiaaicdaaeqaaOWaaqWaaeaacaWGNbaacaGLhWUaayjcSdGaamizai aadMgacaWGZbGaamiDaaaa@4620@
    Where,
    d i s t = n d i s t MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqGqFfpeea0xe9vq=Jb9 vqpeea0xd9q8qiYRWxGi6xij=hbba9q8aq0=yq=He9q8qiLsFr0=vr 0=vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaWGKbGaam yAaiaadohacaWG0bGaeyypa0JaaCOBaiabgwSixlaahsgacaWHPbGa aC4Caiaahshaaaa@434F@
    Signed distance
    ρ 0
    Reference density of the element
    Signed distance is computed from element centroid to reference surface. Initial pressure in a given element is:(2)
    P = P r e f + ρ 0 ( d i s t ) | g | d i s t MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqGqFfpeea0xe9vq=Jb9 vqpeea0xd9q8qiYRWxGi6xij=hbba9q8aq0=yq=He9q8qiLsFr0=vr 0=vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaWGqbGaey ypa0JaamiuamaaBaaaleaacaWGYbGaamyzaiaadAgaaeqaaOGaey4k aSIaeqyWdi3aaSbaaSqaaiaaicdaaeqaaOWaaeWaaeaacaWGKbGaam yAaiaadohacaWG0baacaGLOaGaayzkaaWaaqWaaeaacaWGNbaacaGL hWUaayjcSdGaamizaiaadMgacaWGZbGaamiDaaaa@4DD3@
    Where, ρ 0 ( d i s t ) MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqGqFfpeea0xe9vq=Jb9 vqpeea0xd9q8qiYRWxGi6xij=hbba9q8aq0=yq=He9q8qiLsFr0=vr 0=vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacqaHbpGCda WgaaWcbaGaaGimaaqabaGcdaqadaqaaiaadsgacaWGPbGaam4Caiaa dshaaiaawIcacaGLPaaaaaa@3F69@ is the reference density of the given element.


    Figure 1.
  4. Same pressure value is applied on all integration point of the elements.
  5. If /INIVOL option is used to initialize volumetric fraction with LAW51 then reference density is automatically computed from initial volumetric fractions.
  6. Currently only compatible with hydrodynamic LAW3, 4, 6, 37, 49, 51 (ALE, EULER).
  7. The grav_ID card must reference a gravity /GRAV with a constant gravity function fct_IDT from t=0; or, the function can be left blank and the constant gravity value defined in /GRAV, FscaleY.


    Figure 2.