/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
ρ i ρ 0            
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)

  
ρ i Initial density.

(Real)

 [ kg m 3 ]
ρ 0 Reference density used in E.O.S (equation of state).

Default ρ 0 = ρ i (Real)

 [ kg m 3 ]
c Speed of sound.

(Real)

 [ m s ] MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaamWaaeaada Wcaaqaaiaab2gaaeaacaqGZbaaaaGaay5waiaaw2faaaaa@39DE@
ν Molecular kinematic viscosity.

(Real)

 [ m 2 s ]
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)

 [ 1 s ]

Example (Fluid)

#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/MAT/LAW46/5
FLUID (unit: kg_m_s)
#              RHO_I
              1562.5
#                  c                  NU
               593.3              2.4e-6
#     Isgs                 C_s                 Csp
         2                   0                   0
/EULER/MAT/5
#     Modif. factor.
                   0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#ENDDATA
/END
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Comments

  1. For Isgs = 1 or 2, Δ = Volume 3 .
  2. For Isgs = 3, Δ is the smallest dimension of each element.
  3. ν sgs is computed as:(1)
    ν sgs = ( Cs Δ ) 2 ( e ij ) 1 2
  4. This law is modified near wall boundaries:

    ν + ν sgs = ν ⋅ k ⋅ y 2 + ln ⁡ ( E y 2 + ) if y 2 + ≥ 11.225

    ν sgs = 0 , otherwise.

    Where,
    ν sgs
    Sub grid scale viscosity
    k MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4Aaaaa@36E7@
    von Kahrman constant