about the application of drag coefficient

[nadir0707]

I want to study the impact of the drug coefficient on the flame and the fire spread within a semi confined environment.Using a pool fire as a fire source .However, I'm not sure how to apply the drag coefficient. What I did in the input file is applying the drag coefficient on part line.Should I also include the darg coefficient in the obstructions and other surfaces lines?
thank you in advence

&SURF ID='fire' , HRRPUA=1000 /

&SURF ID='the pan '
MATL_ID = 'pan'
GEOMETRY= 'SPHERICAL'
THICKNESS = 0.006 /

POOL FIRE-----------------------------------------

&VENT XB= 5.6, 6.9, 0.2, 0.7, 0, 0, SURF_ID = 'fire', /

---

&PART ID='smoke'
SURF_ID='the pan'
DRAG_COEFFICIENT=0.10
STATIC = .TRUE. /

&INIT N_PARTICLES_PER_CELL=10, CELL_CENTERED=.TRUE , PART_ID='smoke', XB=5.6, 6.9, 0.2, 0.7, 0, 0, /

[rmcdermo]

You have a confusing set of inputs. I cannot tell what you are trying to do (you are applying a drag coefficient to a pan?). Play with drag independent from the fire to start. Follow the examples in fds/Verification/Sprinklers_and_Sprays. For example, sphere_drag_1.fds

[nadir0707]

dear rmcdermo thank you for your reply this is the complete input file what i m trying to see is the impact of the drag coefficient on the fire spread within the semi confined environment, i applied it to the part line but do i need to apply it to the obst line and the surf line also ?

HEAD CHID='pool_fire_pan_test', TITLE='pool_fire_pan_test' /

&TIME T_END=300 /
&DUMP DT_RESTART=10 /
MISC RESTART=.TRUE. /

&MESH IJK=140,50,32, XB=0 ,7 ,0 ,2.5 ,0 ,1.6 /

---

&REAC FUEL = 'fuel'
SOOT_YIELD = 0.01
CO_YIELD = 0.27
C = 10
H = 22
/

&MATL ID = 'fire blocking layers'
SPECIFIC_HEAT = 1.42
CONDUCTIVITY = 0.04
DENSITY = 1000
N_REACTIONS = 1
NU_SPEC = 1.
SPEC_ID = 'fuel'
REFERENCE_TEMPERATURE = 280.
HEAT_OF_REACTION = 1000.
HEAT_OF_COMBUSTION = 15000. /

&MATL ID = 'FOAM'
SPECIFIC_HEAT = 1.4
CONDUCTIVITY = 0.05
DENSITY = 40
N_REACTIONS = 1
NU_SPEC = 1.
SPEC_ID = 'fuel'
REFERENCE_TEMPERATURE = 300.
HEAT_OF_REACTION = 800.
HEAT_OF_COMBUSTION = 26000. /

&MATL ID = 'CARPET PILE'
CONDUCTIVITY = 0.05
SPECIFIC_HEAT = 1.3
DENSITY = 900.
N_REACTIONS = 1
NU_SPEC = 1.
SPEC_ID = 'fuel'
REFERENCE_TEMPERATURE = 290.
HEAT_OF_COMBUSTION = 22000.
HEAT_OF_REACTION = 2000. /

&MATL ID = 'epoxy-Fiberglas pnel'
DENSITY = 116.
EMISSIVITY = 0.8
CONDUCTIVITY = 0.05
SPEC_ID = 'fuel'
SPECIFIC_HEAT = 2.09 /

&MATL ID = 'ALUMINIUM'
CONDUCTIVITY = 0.237
SPECIFIC_HEAT = 0.897
DENSITY = 230. /

&MATL ID='pan'
CONDUCTIVITY = 1
SPECIFIC_HEAT = 1.5
DENSITY = 1200. /

&SURF ID = 'UPHOLSTERY'
COLOR = 'BLUE'

  BURN_AWAY      = .TRUE.
  MATL_ID(1:2,1) = 'fire blocking layers','FOAM'
  THICKNESS(1:2) = 0.007,0.1 /

&SURF ID = 'CARPET'
MATL_ID = 'CARPET PILE'
COLOR = 'SLATE GRAY'
BACKING = 'INSULATED'
THICKNESS = 0.006 /

&SURF ID = 'WALL'
MATL_ID = 'ALUMINIUM','epoxy-Fiberglas pnel'
COLOR = 'SILVER'
TRANSPARENCY=0.3
BACKING = 'EXPOSED'
THICKNESS = 0.04,0.06 /

&SURF ID = 'PANELS '
MATL_ID = 'epoxy-Fiberglas pnel'
IGNITION_TEMPERATURE = 505.
COLOR = 'INVISIBLE'
BACKING = 'INSULATED'
THICKNESS = 0.06 /

---

&SURF ID='fire' , HRRPUA=2000 /

&SURF ID='the pan '
MATL_ID = 'pan'
GEOMETRY= 'SPHERICAL'
THICKNESS = 0.006 /

POOL FIRE-----------------------------------------

&VENT XB= 5.6, 6.9, 0.2, 0.7, 0, 0, SURF_ID = 'fire', /

---

&PART ID='smoke'
SURF_ID='the pan'
DRAG_COEFFICIENT=0.10
STATIC = .TRUE. /

&INIT N_PARTICLES_PER_CELL=10, CELL_CENTERED=.TRUE , PART_ID='smoke', XB=5.6, 6.9, 0.2, 0.7, 0, 0, /
the airplane walls-------------------------------------------------------------------
&OBST XB= 6.8, 7, 0.7, 0.8, 0, 1.6, SURF_ID ='WALL'/
&OBST XB= 5.5, 6.8, 0.7, 0.8, 1.4, 1.6, SURF_ID ='WALL'/
&OBST XB= 1, 5.5, 0.7, 0.8, 0, 1.6, SURF_ID ='WALL'/
&OBST XB= 0, 1, 0.7, 0.8, 0, 0.4, SURF_ID ='WALL'/
&OBST XB= 0, 1, 0.7, 0.8, 1.2, 1.6, SURF_ID ='WALL'/
&OBST XB= 0, 0.4, 0.7, 0.8, 0.4, 1.2, SURF_ID ='WALL'/

&OBST XB= 0, 7, 2.2, 2.3, 0, 1.6, SURF_ID ='WALL'/
ceilling------------------------------------------------------------------------
&OBST XB= 0, 7, 0.8, 2.2, 1.55, 1.6, SURF_ID = 'PANELS '/

floor----------------------------------------------------------------------------
&OBST XB= 0, 7, 0.8, 2.2, 0, 0.05, SURF_ID='CARPET'/

seats --------------------------------------------------------------------------
1
&OBST XB= 6.9, 7, 0.8, 2.2, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 6.5, 7, 0.8, 2.2, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

2
&OBST XB= 6.1, 6.2, 1.2, 1.7, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 5.7, 6.2, 1.2, 1.7, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

&OBST XB= 6.1, 6.2, 1.7, 2.2, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 5.7, 6.2, 1.7, 2.2, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

3
&OBST XB= 5.4, 5.5, 0.8, 1.3, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 5, 5.5, 0.8, 1.3, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

&OBST XB= 5.4, 5.5, 1.7, 2.2, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 5, 5.5, 1.7, 2.2, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

4
&OBST XB= 4.7, 4.8, 0.8, 1.3, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 4.3, 4.8, 0.8, 1.3, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

&OBST XB= 4.7, 4.8, 1.7, 2.2, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 4.3, 4.8, 1.7, 2.2, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

5
&OBST XB= 4, 4.1, 0.8, 1.3, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 3.6, 4.1, 0.8, 1.3, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

&OBST XB= 4, 4.1, 1.7, 2.2, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 3.6, 4.1, 1.7, 2.2, 0.4, 0.5, SURF_ID='UPHOLSTERY' /

6
&OBST XB= 3.3, 3.4, 0.8, 1.3, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 2.9, 3.4, 0.8, 1.3, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

&OBST XB= 3.3, 3.4, 1.7, 2.2, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 2.9, 3.4, 1.7, 2.2, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

7
&OBST XB= 2.6, 2.7, 0.8, 1.3, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 2.2, 2.7, 0.8, 1.3, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

&OBST XB= 2.6, 2.7, 1.7, 2.2, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 2.2, 2.7, 1.7, 2.2, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

8
&OBST XB= 1.9, 2, 0.8, 1.3, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 1.5, 2, 0.8, 1.3, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

&OBST XB= 1.9, 2, 1.7, 2.2, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 1.5, 2, 1.7, 2.2, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

9
&OBST XB= 1.2, 1.3, 0.8, 1.3, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 0.8, 1.3, 0.8, 1.3, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

&OBST XB= 1.2, 1.3, 1.7, 2.2, 0.5, 1.1, SURF_ID='UPHOLSTERY'/
&OBST XB= 0.8, 1.3, 1.7, 2.2, 0.4, 0.5, SURF_ID='UPHOLSTERY'/

---

temperature at center seat row -------------------------------------

&DEVC XYZ=1.3,1.5,1.35, QUANTITY='TEMPERATURE',ID='TEMP_8row', IOR=3/
&DEVC XYZ=4.1,1.5,1.35, QUANTITY='TEMPERATURE',ID='TEMP_5row', IOR=3/
&DEVC XYZ=6.2,1.5,1.35, QUANTITY='TEMPERATURE',ID='TEMP_1row', IOR=3/

O2 fraction -------------------------------------------------------
&DEVC XYZ=0.8,0.8,0.45, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN', ID='EO2_0.45m' /
&DEVC XYZ=0.8,0.8,0.9, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN', ID='EO2_1.06m' /
&DEVC XYZ=0.8,0.8,1.35, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN', ID='EO2_1.67m' /

CO2 fraction----------------------------------------------------------------
&DEVC XYZ=0.8,0.8,0.45, QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON DIOXIDE', ID='ECO2_0.45m' /
&DEVC XYZ=0.8,0.8,0.9, QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON DIOXIDE', ID='ECO2_1.06m' /
&DEVC XYZ=0.8,0.8,1.35, QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON DIOXIDE', ID='ECO2_1.67m' /

CO fraction ----------------------------------------------------------------
&DEVC XYZ=0.8,1.5,0.45, QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON MONOXIDE ', ID='ECO_0.45m' /
&DEVC XYZ=0.8,1.5,0.9, QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON MONOXIDE ', ID='ECO_1.06m' /
&DEVC XYZ=0.8,1.5,1.35, QUANTITY='VOLUME FRACTION',SPEC_ID='CARBON MONOXIDE ', ID='ECO_1.67m' /

O2 fraction SP -------------------------------------------------------

&DEVC XYZ=0.8,1.5,0.45, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN', ID='SPEO2_0.45m' /
&DEVC XYZ=0.8,1.5,0.9, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN', ID='SPEO2_1.06m' /
&DEVC XYZ=0.8,1.5,1.35, QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN', ID='SPEO2_1.67m' /

CO2 fraction SP----------------------------------------------------------------

&DEVC XYZ=0.8,1.5,0.45, QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON DIOXIDE', ID='SPECO2_0.45m' /
&DEVC XYZ=0.8,1.5,0.9, QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON DIOXIDE', ID='SPECO2_1.06m' /
&DEVC XYZ=0.8,1.5,1.35, QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON DIOXIDE', ID='SPECO2_1.67m' /

CO fraction SP----------------------------------------------------------------

&DEVC XYZ=0.8,1.5,0.45, QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON MONOXIDE ', ID='SPECO_0.45m' /
&DEVC XYZ=0.8,1.5,0.9, QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON MONOXIDE ', ID='SPECO_1.06m' /
&DEVC XYZ=0.8,1.5,1.35, QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON MONOXIDE ', ID='SPECO_1.67m' /

temperature at the rear door-----------------------------------------------------------

&DEVC XYZ=0.8,0.85,0.4, QUANTITY='TEMPERATURE',ID='TEMP_aftdoor1', IOR=3/
&DEVC XYZ=0.8,0.85,0.4, QUANTITY='TEMPERATURE',ID='TEMP_aftdoor2', IOR=3/
&DEVC XYZ=0.8,0.85,0.4, QUANTITY='TEMPERATURE',ID='TEMP_aftdoor3', IOR=3/
&DEVC XYZ=0.8,0.85,0.4, QUANTITY='TEMPERATURE',ID='TEMP_aftdoor4', IOR=3/
&DEVC XYZ=0.8,0.85,0.4, QUANTITY='TEMPERATURE',ID='TEMP_aftdoor5', IOR=3/

&DEVC XYZ=0.8,1.5,0.4, QUANTITY='TEMPERATURE',ID='TEMP_aftdoorSP1', IOR=3/
&DEVC XYZ=0.8,1.5,0.4, QUANTITY='TEMPERATURE',ID='TEMP_aftdoorSP2', IOR=3/
&DEVC XYZ=0.8,1.5,0.4, QUANTITY='TEMPERATURE',ID='TEMP_aftdoorSP3', IOR=3/
&DEVC XYZ=0.8,1.5,0.4, QUANTITY='TEMPERATURE',ID='TEMP_aftdoorSP4', IOR=3/
&DEVC XYZ=0.8,1.5,0.4, QUANTITY='TEMPERATURE',ID='TEMP_aftdoorSP5', IOR=3/

HEAT FLUX---------------------------------------------------------------

&DEVC XYZ=6.4,1.5,0.0, QUANTITY='TOTAL HEAT FLUX',ID='TOTAL HF_1', IOR=3 /
&DEVC XYZ=4.1,1.5,0.0, QUANTITY='TOTAL HEAT FLUX',ID='TOTAL HF_2', IOR=3 /
&DEVC XYZ=1,1.5,0.0, QUANTITY='TOTAL HEAT FLUX',ID='TOTAL HF_3', IOR=3 /

&DEVC XYZ=6.4,1.5,0.0, QUANTITY='RADIATIVE HEAT FLUX',ID='RAD HF_1', IOR=3 /
&DEVC XYZ=4.1,1.5,0.0, QUANTITY='RADIATIVE HEAT FLUX',ID='RAD HF_2', IOR=3 /
&DEVC XYZ=1,1.5,0.0, QUANTITY='RADIATIVE HEAT FLUX',ID='RAD HF_3', IOR=3 /

---

slices --------------------------------------------------------------------------------------
TEMPERATURE
&SLCF PBZ=1.2, QUANTITY='TEMPERATURE',VECTOR=.TRUE. /
&SLCF PBZ=0.6, QUANTITY='TEMPERATURE' ,VECTOR=.TRUE. /
&SLCF PBX=0.8, QUANTITY='TEMPERATURE' ,VECTOR=.TRUE. /
&SLCF PBX=6.2, QUANTITY='TEMPERATURE',VECTOR=.TRUE. /
&SLCF PBY=0.8, QUANTITY='TEMPERATURE',VECTOR=.TRUE. /
&SLCF PBY=0.9, QUANTITY='TEMPERATURE',VECTOR=.TRUE. /
&SLCF PBY=1.5, QUANTITY='TEMPERATURE',VECTOR=.TRUE. /

HRRPUV
&SLCF PBX=6.2, QUANTITY='HRRPUV',VECTOR=.TRUE. / Heat Release Rate per Unit area
&SLCF PBZ=0.6, QUANTITY='HRRPUV' ,VECTOR=.TRUE./ Heat Release Rate per Unit area
&SLCF PBY=0.8, QUANTITY='HRRPUV' ,VECTOR=.TRUE./ Heat Release Rate per Unit area
&SLCF PBY=0.9, QUANTITY='HRRPUV' ,VECTOR=.TRUE./ Heat Release Rate per Unit area
&SLCF PBY=1.5, QUANTITY='HRRPUV' ,VECTOR=.TRUE./ Heat Release Rate per Unit area

OXYGEN
&SLCF PBZ=0.60, QUANTITY='VOLUME FRACTION',VECTOR=.TRUE., SPEC_ID='OXYGEN ' /
&SLCF PBY=0.8, QUANTITY='VOLUME FRACTION',VECTOR=.TRUE., SPEC_ID='OXYGEN ' /
&SLCF PBY=1.5, QUANTITY='VOLUME FRACTION',VECTOR=.TRUE., SPEC_ID='OXYGEN ' /

CARBON DIOXIDE
&SLCF PBZ=0.60, QUANTITY='VOLUME FRACTION',VECTOR=.TRUE., SPEC_ID='CARBON DIOXIDE ' /
&SLCF PBY=0.8, QUANTITY='VOLUME FRACTION',VECTOR=.TRUE., SPEC_ID='CARBON DIOXIDE ' /
&SLCF PBY=1.5, QUANTITY='VOLUME FRACTION',VECTOR=.TRUE., SPEC_ID='CARBON DIOXIDE ' /

CARBON MONOXIDE
&SLCF PBZ=0.60, QUANTITY='VOLUME FRACTION',VECTOR=.TRUE., SPEC_ID='CARBON MONOXIDE ' /
&SLCF PBY=0.8, QUANTITY='VOLUME FRACTION',VECTOR=.TRUE., SPEC_ID='CARBON MONOXIDE ' /
&SLCF PBY=1.5, QUANTITY='VOLUME FRACTION',VECTOR=.TRUE., SPEC_ID='CARBON MONOXIDE ' /

---

&VENT MB='ZMAX' , SURF_ID='OPEN' /
&VENT MB='YMIN' , SURF_ID='OPEN' /
&VENT MB='YMAX' , SURF_ID='OPEN' /

[rmcdermo]

You don't apply a drag coefficient to an OBST. You need to read the manuals and understand the code. I suggested the way to start this was to first study the simple drag cases with particles in the verification suite. Then you should study fire independently. And when you understand them both well, you can combine them if that is appropriate.

[nadir0707]

thank for your time, i will get on it.