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/MAT/LAW46 (LES_FLUID)

Block Format Keyword Describes the viscous fluid material with sub-grid scale viscosity.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/MAT/LAW46/mat_ID/unit_ID or /MAT/LES_FLUID/mat_ID/unit_ID
mat_title
ρi ρ0            
c ν            
Isgs Cs Csp          

Definition

Field Contents SI Unit Example
mat_ID Material identifier.

(Integer, maximum 10 digits)

 
mat_title Material title.

(Character, maximum 100 characters)

 
unit_ID Unit Identifier.

(Interger, maximum 10 digits)

 
ρi Initial density.

(Real)

[kgm3]
ρ0 Reference density used in E.O.S (equation of state).

Default ρ0=ρi (Real)

[kgm3]
c Speed of sound.

(Real)

[ms]
ν Molecular kinematic viscosity.

(Real)

[m2s]
Isgs Sub-grid scale model.
= 0
No sub-grid viscosity.
= 1 (Default)
Smagorinsky model.
= 2
Smagorinsky with acoustic damping.
= 3
Identical to Isgs =2 with modified Δ value.

(Integer)

 
Cs Smagorinsky constant.

Default = 0.1 (Real)

 
Csp Pressure damping coefficient.

Default = Cs (Real)

[1s]

Example (Fluid)

Comments

  1. For Isgs = 1 or 2, Δ=3Volume .
  2. For Isgs = 3, Δ is the smallest dimension of each element.
  3. νsgs is computed as:(1)
    νsgs=(CsΔ)2(eij)12
  4. This law is modified near wall boundaries:

    ν+νsgs=νky+2ln(Ey+2) if y+211.225

    νsgs=0 , otherwise.

    Where,
    νsgs
    Sub grid scale viscosity
    k
    von Kahrman constant