/INIVOL

Block Format Keyword For multi-material ALE modeling, this initial condition defines the initial volumetric fractions on a side of a defined surface.

By using this option, the fluid mesh does not need to follow the contour of the Lagrangian structure which allows a Cartesian mesh to be used. A surface is used to define the fluids in each volume.


Figure 1.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/INIVOL/part_ID/inivol_ID
inivol_title
surf_ID ALE_PHASE FILL_OPT ICUMU FILL_RATIO        
surf_ID ALE_PHASE FILL_OPT ICUMU FILL_RATIO        
etc etc etc etc etc        
surf_IDn ALE_PHASE FILL_OPT ICUMU FILL_RATIO        

Definitions

Field Contents SI Unit Example
part_ID Part of multi-material ALE elements to be filled. 1

(Integer, maximum 10 digits)

  
inivol_ID Initial volume fraction identifier.

(Integer, maximum 10 digits)

  
inivol_title Initial volume fraction title.

(Character, maximum 100 characters)

  
surf_IDn Surface identifier. 5

(Integer)

  
ALE_PHASE Phase of the multi-material ALE to fill elements. 3

(Integer)

  
FILL_OPT Reverse normal vectors. 1
= 0 (Default)
Filling the side along the normal direction of surface.
= 1
Filling the reverse side (opposite of the normal direction of surface).

(Integer)

  
ICUMU Cumulative filling. 4
= 0 (Default)
Erase existing filling.
= 1
Cumulative filling.

(Integer)

  
FILL_RATIO Volumetric Fraction to add in related elements. 4

0.0 ≤ FILL_RATIO ≤ 1.0

Default = 1.0 (Real)

  

Comments

  1. During Starter execution, the elements belonging to the PART defined by part_ID are filled with a given volumetric fraction depending on ALE_PHASE value. The only requirement is that the element is on the correct side of the given oriented surface. To fill the elements on the opposite side of the surface normal, use the FILL_OPT =1. In Figure 2 the green color indicates the side of the surface which is filled by the /INIVOL option.


    Figure 2. Surface side to fill can be reversed using flag FILL_OPT
  2. If an element is crossed by the surface, then it is not fully on one side. Then a volume estimation is made to fill only the relevant sub-volume on the related side of the surface.


    Figure 3. Element crossed by the surface has 2 sides. INIVOL option considers only relevant portion
  3. ALE_PHASE is the multimaterial ALE phase ID which is used to fill the given side of the surface. Since /MAT/LAW51 has 4 sub-materials, a value from 1 to 4 must be entered.
  4. ICUMU flag can be used to add another material to a volume. For this purpose a FILL_RATIO must be provided. By default, ICUMU=0, which means that the existing volumetric fraction initialized with a previous /INIVOL process will be erased.


    Figure 4. Filling with ICUMU = 0, erase existing filled volumes (default behavior)
    During the 2nd step, the volume outside the disc is filled with the phase 3 material.


    Figure 5. Filling with ICUMU = 1, volumetric fraction is added into existing filled volumes

    During the 3rd step, the phase 1 material is added to the existing phase 3 material resulting in a 50% mixture of phase 1 and phase 3 material.

  5. A well-defined initial condition for volumetric fraction is such that the volume fraction.(1)
    α = ( α 1 , α 2 , α 3 , α 4 ) MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqySdeMaey ypa0Jaaiikaiabeg7aHnaaBaaaleaacaaIXaaabeaakiaacYcacqaH XoqydaWgaaWcbaGaaGOmaaqabaGccaGGSaGaeqySde2aaSbaaSqaai aaiodaaeqaaOGaaiilaiabeg7aHnaaBaaaleaacaaI0aaabeaakiaa cMcaaaa@464B@
    Satisfies:(2)
    α i = v i V ∈ [ 0 , 1 ] MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqySde2aaS baaSqaaiaadMgaaeqaaOGaeyypa0ZaaSaaaeaacaWG2bWaaSbaaSqa aiaadMgaaeqaaaGcbaGaamOvaaaacqGHiiIZcaGGBbGaaGimaiaacY cacaaIXaGaaiyxaaaa@4233@
    and(3)
    ∑ i = 1 4 α i = 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaabCaeaacq aHXoqydaWgaaWcbaGaamyAaaqabaGccqGH9aqpcaaIXaaaleaacaWG PbGaeyypa0JaaGymaaqaaiaaisdaa0GaeyyeIuoaaaa@402A@
    If this condition is not met after all /INIVOL processes, then:
    • If ∑ i = 1 4 α i > 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaabCaeaacq aHXoqydaWgaaWcbaGaamyAaaqabaGccqGH+aGpcaaIXaaaleaacaWG PbGaeyypa0JaaGymaaqaaiaaisdaa0GaeyyeIuoaaaa@402C@ error message will be displayed.
    • If ∑ i = 1 4 α i < 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaabCaeaacq aHXoqydaWgaaWcbaGaamyAaaqabaGccqGH8aapcaaIXaaaleaacaWG PbGaeyypa0JaaGymaaqaaiaaisdaa0GaeyyeIuoaaaa@4028@ phase 1 is used to fill the remaining unoccupied volume.
    Unoccupied sub-volume are automatically filled with phase 1 after all execution of /INIVOL options to ensure that element volume is correctly partitioned.


    Figure 6. Unoccupied sub-volume are automatically filled with phase 1
  6. Supported surfaces are:
    • 3-node and 4-node shells. Shell surface (as container) should be fully-closed.
    • Infinite plane (/SURF/PLANE)

    Surface can be based on VOID property (/PROP/VOID) and on VOID material law (/MAT/VOID). This is recommended to avoid any constraining time step calculation for the INIVOL surface because it is only used during the initialization. Otherwise, a rigid body can also be defined for the surface.