/MAT/LAW46 (LES_FLUID)
Block Format Keyword Describes the viscous fluid material with subgrid 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  
${\rho}_{i}$  ${\rho}_{0}$  
c  $\nu $  
I_{sgs}  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) 

${\rho}_{i}$  Initial
density. (Real) 
$\left[\frac{\text{kg}}{{\text{m}}^{\text{3}}}\right]$ 
${\rho}_{0}$  Reference density
used in E.O.S (equation of state). Default ${\rho}_{0}={\rho}_{i}$ (Real) 
$\left[\frac{\text{kg}}{{\text{m}}^{\text{3}}}\right]$ 
c  Speed of
sound. (Real) 
$\left[\frac{\text{m}}{\text{s}}\right]$ 
$\nu $  Molecular kinematic
viscosity. (Real) 
$\left[\frac{{\text{m}}^{\text{2}}}{\text{s}}\right]$ 
I_{sgs}  Subgrid scale model.
(Integer) 

Cs  Smagorinsky
constant. Default = 0.1 (Real) 

Csp  Pressure damping
coefficient. Default = Cs (Real) 
$\left[\frac{\text{1}}{\text{s}}\right]$ 
Example (Fluid)
#RADIOSS STARTER
#12345678910
/MAT/LAW46/5
FLUID (unit: kg_m_s)
# RHO_I
1562.5
# c NU
593.3 2.4e6
# Isgs C_s Csp
2 0 0
/EULER/MAT/5
# Modif. factor.
0
#12345678910
#ENDDATA
/END
#12345678910
Comments
 For I_{sgs} = 1 or 2, $\mathrm{\text{\Delta}}\text{=}\sqrt[\text{3}]{\mathit{Volume}}$ .
 For I_{sgs} = 3, $\mathrm{\text{\Delta}}$ is the smallest dimension of each element.

${\nu}_{\mathit{sgs}}$
is computed as:
(1) $${\nu}_{\mathit{sgs}}={(\mathit{Cs}\mathrm{\text{\Delta}})}^{2}{({e}_{\mathit{ij}})}^{\frac{1}{2}}$$  This law is modified
near wall boundaries:
$\nu +{\nu}_{\mathit{sgs}}=\frac{\nu \cdot k\cdot {y}_{2}^{+}}{\mathrm{ln}(E{y}_{2}^{+})}$ if ${y}_{2}^{+}\ge 11.225$
${\nu}_{\mathit{sgs}}=0$ , otherwise.
Where, ${\nu}_{\mathit{sgs}}$
 Sub grid scale viscosity
 $k$
 von Kahrman constant