/PROP/TYPE15 (POROUS)

Block Format Keyword Describes the porous solid element property set (extended Darcy's law).

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/PROP/TYPE15/prop_ID or /PROP/POROUS/prop_ID
prop_title
Blank Format
qa qb h        
Por                
R1 R2 R3        
skew_IDr Ihon                
Itu α lmix          
node_ID                  

Definitions

Field Contents SI Unit Example
prop_ID Property identifier

(Integer, maximum 10 digits)

  
prop_title Property title

(Character, maximum 100 characters)

  
qa Quadratic bulk viscosity

Default = 10-20 (Real)

  
qb Linear bulk viscosity

Default = 10-20 (Real)

  
h Hourglass viscosity coefficient

Default = 0.10 (Real)

  
Por Porosity

Default = 1.0 (Real)

  
R1 Specific resistance factor in direction 1

Default = 0.0 (Real)

  
R2 Specific resistance factor in direction 2

Default = 0.0 (Real)

  
R3 Specific resistance factor in direction 3

Default = 0.0 (Real)

  
skew_IDr Skew identifier for resistance orthotropy

(Integer)

  
Ihon Honeycomb substrate flag.
=1
Resistance applies only in direction 1 of skew_IDr and velocities are constrained in directions 2 and 3.

Default = 0.0 (Integer)

  
Itu Turbulence imposed by medium flag. 7
= 0
Turbulence is done according to k − ε MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaWGRbGaey OeI0IaeqyTdugaaa@39E3@ model.
= 1
Turbulence is imposed by porous model.

Default = 0.0 (Integer)

  
α Turbulence coefficient for honeycomb substrate.

Default = 0.1 (Real)

  
lmix Turbulence mixing length.

(Real)

 [m]
node_ID Main node identifier of rigid body modeling rigid substrate.

Default = 0 (Integer)

  

Example (Air)

#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/PROP/POROUS/4
AIR (unit kg_m_s)

#                q_a                 q_b                   h
               1E-20               1E-20                   0
#                Por
                   1
#                 R1                  R2                  R3
                 400                 400                 400
# skew_IDr      Ihon
         0         0
#      Itu               alpha               I_mix
         0                   0                   0
#rbody_IDs
         0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#enddata
/END
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Example (Gas)

#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/PROP/POROUS/13
GAS (unit kg_m_s)

#                q_a                 q_b                   h
                 1.1                 .05                   0
#                Por
                   0
#                 R1                  R2                  R3
                3500                   0                   0
# skew_IDr      Ihon
         3         1
#      Itu               alpha               I_mix
         1                 .05                .003
#rbody_IDs
     43218
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#enddata
/END
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Comments

  1. The qa and qb default values are equal to 1.10 and 0.05 in non-CFD versions.
  2. Porosity (relative volume of pores) is taken into account for 3D Euler materials only. Porosity is otherwise set to 1.
  3. F i = − m R i j V j MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaWGgbWaaS baaSqaaiaadMgaaeqaaOGaeyypa0JaeyOeI0IaamyBaiaadkfadaWg aaWcbaGaamyAaiaadQgaaeqaaOGaamOvamaaBaaaleaacaWGQbaabe aaaaa@4013@ is added to nodal force vector, R i j MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaWGsbWaaS baaSqaaiaadMgacaWGQbaabeaaaaa@393F@ being the tension representation of the specific resistance factor in the global skew system.
  4. If all resistance factors are set to 0, no computation is performed but the grid velocity can be tied to rigid body node_ID (Line 9).
  5. Specific resistances along orthotropic axis are defined in Line 7 with respect to skew_IDr (by default global system).
  6. Relevant only if material is material law 6 with k − ε turbulence.
  7. If Itu =1, turbulence is imposed by porous model.(1)
    k= ( αV ) 2 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaWGRbGaey ypa0ZaaeWaaeaacqaHXoqycaWGwbaacaGLOaGaayzkaaWaaWbaaSqa beaacaaIYaaaaaaa@3D41@
    and(2)
    ε= k 1.5 l mix MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaacqaH1oqzcq GH9aqpdaWcaaqaaiaadUgadaahaaWcbeqaaiaaigdacaGGUaGaaGyn aaaaaOqaaiaadYgadaWgaaWcbaGaamyBaiaadMgacaWG4baabeaaaa aaaa@4069@
  8. Fluid reaction force vector and moment are transmitted to specified rigid body; this option is available in 3D only.
  9. Grid velocity is computed according to node_ID rigid body movement. This option is useful to impose such a movement to a grid, even for non-porous material.