FDS Verification Guide: update sphere_drag_1 to include Cd=50 and 100; tighten time accuracy

Author: rmcdermo

Manuals/FDS_Verification_Guide/FDS_Verification_Guide.tex

@@ -5896,9 +5896,9 @@ \subsection{Stationary Spherical Particles in a Duct (\texorpdfstring{\ct{sphere
 \label{sphere_drag_1}
 \label{sphere_drag_2}
 
-Consider a 2~m long duct with a 1~m square cross section, fixed air velocity of $u_0=2$~m/s, and free-slip walls. Three ducts are stacked vertically, each with its own mesh and a plane of particles spanning the duct at its center point. The particles are 1~cm in diameter and 10~particles are specified in each grid cell. The expected pressure drop is given by the formula:
+Consider a 2~m long duct with a 1~m square cross section, fixed air velocity of $u_0=2$~m/s, and free-slip walls. Five ducts are stacked vertically, each with its own mesh and a plane of particles spanning the duct at its center point. The particles are 1~cm in diameter and 10~particles are specified in each grid cell. The expected pressure drop is given by the formula:
 \be \Delta p=\frac{1}{2} \rho \frac{\sum \, C_{\rm d} \, \pi \, r_{\rm p}^{2} \, u_0^2} {A} \ee
-where $A$ is the 1~m$^2$ cross-sectional area, $\rho=1.2$~kg/m$^3$ is the density of air, and the summation is over 4000 particles. For specified drag coefficients of 5, 10, and 20 in the three ducts, the pressure drops are expected to be 3.77~Pa, 7.54~Pa, and 15.1~Pa.  Comparisons of computed and analytical results are shown in the left hand plot of Fig.~\ref{sphere_drag_fig}.
+where $A$ is the 1~m$^2$ cross-sectional area, $\rho=1.2$~kg/m$^3$ is the density of air, and the summation is over 4000 particles. For specified drag coefficients of [5, 10, 20, 50, 100] in the five ducts, the pressure drops are expected to be [3.77, 7.54, 15.08, 37.70, 75.40] Pa.  Comparisons of computed and analytical results are shown in the left hand plot of Fig.~\ref{sphere_drag_fig}.  Note that accurate steady state pressure drop for high drag forces may require small time steps because FDS explicitly time marches to the steady solution.  In such cases, \ct{PARTICLE\_CFL\_MAX=0.1} may be required to achieve stable and accurate results.
 
 In a second test case, consider a single 10~m long, 1~m square duct. Spherical particles 2~mm in diameter with a density of 514~kg/m$^3$ are randomly distributed in the section of the duct between 4~m and 5~m from the upstream end. The particle mass per unit volume is set to 1.66~kg/m$^3$. The number of particles included in the simulation is 10000, which means that each particle actually represents 77.1 real particles. The drag coefficient is approximately 1.6, based on the local Reynolds number, which is about 40. The free stream velocity in the duct is 0.3~m/s, but the speed varies slightly within the cloud of particles. The pressure is expected to drop linearly from approximately 0.21~Pa to 0~Pa over the 1~m of duct filled by particles, as shown in the right hand plot of Fig.~\ref{sphere_drag_fig}.
 

Utilities/Matlab/FDS_verification_dataplot_inputs.csv

@@ -587,7 +587,7 @@ d,species_conservation_1,Flowfields/species_conservation_1_git.txt,Flowfields/sp
 d,species_conservation_2,Flowfields/species_conservation_2_git.txt,Flowfields/species_conservation_2.csv,2,3,Time,M1|M2,Exact Zone 1 Mass|Exact Zone 2 Mass,ko|ro,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Flowfields/species_conservation_2_devc.csv,2,3,Time,M1|M2,FDS Zone 1 Mass|FDS Zone 2 Mass,k-|r-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Mass (species\_conservation\_2),Time (s),Mass (kg),0,25,1,-0.1,1.1,1,no,0.05 0.90,West,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/species_conservation_2,Absolute Error,end,1.00E-02,Flowfields,r*,r,TeX
 d,species_conservation_3,Flowfields/species_conservation_3_git.txt,Flowfields/species_conservation_3.csv,2,3,Time,Mass N2|Total,Excess N2|Total Evaporated Mass,ko|ro,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Flowfields/species_conservation_3_devc.csv,2,3,Time,Mass N2|Total,FDS (Mass N2)|FDS (Total),k-|r-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Mass (species\_conservation\_3),Time (s),Mass (kg),0,100,1,0,1,1,no,0.05 0.90,West,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/species_conservation_3,Relative Error,end,1.00E-01,Flowfields,r*,r,TeX
 d,species_conservation_4,Flowfields/species_conservation_4_git.txt,Flowfields/species_conservation_4.csv,2,3,Time,Mass Ar|Total,Excess Ar|Total Evaporated Mass,ko|ro,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Flowfields/species_conservation_4_devc.csv,2,3,Time,Mass Ar|Total,FDS (Mass Ar)|FDS (Total),k-|r-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Mass (species\_conservation\_4),Time (s),Mass (kg),0,100,1,-0.1,0.5,1,no,0.05 0.90,West,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/species_conservation_4,Absolute Error,end,5.00E-03,Flowfields,r*,r,TeX
-d,sphere_drag_1,Sprinklers_and_Sprays/sphere_drag_1_git.txt,Sprinklers_and_Sprays/sphere_drag_1.csv,1,2,Time,Exact 5|Exact 10|Exact 20,Exact 5|Exact 10|Exact 20,ko|ro|bo,0,100000,,7,10,-1.00E+09,1.00E+09,0,Sprinklers_and_Sprays/sphere_drag_1_devc.csv,2,3,Time,FDS 5|FDS 10|FDS 20,FDS 5|FDS 10|FDS 20,k-|r-|b-,0,100000,,7,10,-1.00E+09,1.00E+09,0,Pressure Drop (sphere\_drag\_1),Time (s),Pressure Drop (Pa),0,10,1,0,18,1,no,0.05 0.90,West,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/sphere_drag_1,Relative Error,mean,0.05,Sprinklers and Sprays,bs,b,TeX
+d,sphere_drag_1,Sprinklers_and_Sprays/sphere_drag_1_git.txt,Sprinklers_and_Sprays/sphere_drag_1.csv,1,2,Time,Exact 5|Exact 10|Exact 20|Exact 50|Exact 100,Exact 5|Exact 10|Exact 20|Exact 50|Exact 100,ko|ro|bo|mo|co,0,100000,,7,10,-1.00E+09,1.00E+09,0,Sprinklers_and_Sprays/sphere_drag_1_devc.csv,2,3,Time,FDS 5|FDS 10|FDS 20|FDS 50|FDS 100,FDS 5|FDS 10|FDS 20|FDS 50|FDS 100,k-|r-|b-|m-|c-,0,100000,,7,10,-1.00E+09,1.00E+09,0,Pressure Drop (sphere\_drag\_1),Time (s),Pressure (Pa),0,10,1,0,100,1,no,0.05 0.90,West,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/sphere_drag_1,Relative Error,end,0.01,Sprinklers and Sprays,bs,b,TeX
 d,sphere_drag_2,Sprinklers_and_Sprays/sphere_drag_2_git.txt,Sprinklers_and_Sprays/sphere_drag_2.csv,1,2,Length,Pres,Exact,ko,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Sprinklers_and_Sprays/sphere_drag_2_line.csv,2,3,pres-x,pres,FDS,k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Pressure Drop (sphere\_drag\_2),Length (m),Pressure (Pa),0,10,1,0,0.3,1,no,0.05 0.90,East,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/sphere_drag_2,Relative Error,max,0.02,Sprinklers_and_Sprays,bs,b,TeX
 d,spray_burner,Fires/spray_burner_git.txt,Fires/spray_burner.csv,1,2,Time,HRR,Specified (HRR),k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Fires/spray_burner_hrr.csv,2,3,Time,HRR,FDS (HRR),k--,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Heat Release Rate (spray\_burner),Time (s),Heat Release Rate (kW),0,60,1,0,2500,1,no,0.05 0.90,SouthEast,,1,linear,FDS_User_Guide/SCRIPT_FIGURES/spray_burner_HRR,Relative Error,area,0.05,Fires,kd,k,TeX
 d,spreading_fire,Controls/spreading_fire_git.txt,Controls/spreading_fire.csv,1,2,Time,HRR,Specified (HRR),ko,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Controls/spreading_fire_hrr.csv,2,3,Time,HRR,FDS (HRR),k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Heat Release Rate (spreading\_fire),Time (s),Heat Release Rate (kW),0,200,1,0,14000,1,no,0.05 0.90,South,,1,linear,FDS_User_Guide/SCRIPT_FIGURES/spreading_fire_HRR,Relative Error,area,0.05,Fires,kd,k,TeX

Verification/Sprinklers_and_Sprays/sphere_drag_1.csv

@@ -1,5 +1,5 @@
-Time,Exact 5,Exact 10,Exact 20
-7,3.77,7.54,15.07
-8,3.77,7.54,15.07
-9,3.77,7.54,15.07
-10,3.77,7.54,15.07
+Time,Exact 5,Exact 10,Exact 20,Exact 50,Exact 100
+7,3.77,7.54,15.08,37.70,75.40
+8,3.77,7.54,15.08,37.70,75.40
+9,3.77,7.54,15.08,37.70,75.40
+10,3.77,7.54,15.08,37.70,75.40

Verification/Sprinklers_and_Sprays/sphere_drag_1.fds

@@ -3,10 +3,13 @@
 &MESH IJK=40,20,20,XB=0,2,0,1,0,1/
 &MESH IJK=40,20,20,XB=0,2,0,1,1.1,2.1/
 &MESH IJK=40,20,20,XB=0,2,0,1,2.2,3.2/
+&MESH IJK=40,20,20,XB=0,2,0,1,3.3,4.3/
+&MESH IJK=40,20,20,XB=0,2,0,1,4.4,5.4/
 
-&TIME T_END=10. /
+&TIME T_END=10./
+&DUMP DT_DEVC=0.1, DT_SLCF=1.E-6 /
 &RADI RADIATION=.FALSE./
-
+&MISC PARTICLE_CFL_MAX=0.1/
 &VENT MB='XMIN',SURF_ID='VELIN'/
 &VENT MB='XMAX',SURF_ID='OPEN'/
 &VENT MB='YMIN',SURF_ID='SLIP'/
@@ -25,15 +28,20 @@
 &PART ID='DRAG 5',  SURF_ID='PARTICLE', DRAG_COEFFICIENT=5,  STATIC=.TRUE.  /
 &PART ID='DRAG 10', SURF_ID='PARTICLE', DRAG_COEFFICIENT=10, STATIC=.TRUE.  /
 &PART ID='DRAG 20', SURF_ID='PARTICLE', DRAG_COEFFICIENT=20, STATIC=.TRUE.  /
+&PART ID='DRAG 50', SURF_ID='PARTICLE', DRAG_COEFFICIENT=50, STATIC=.TRUE.  /
+&PART ID='DRAG 100', SURF_ID='PARTICLE', DRAG_COEFFICIENT=100, STATIC=.TRUE.  /
 
 &INIT N_PARTICLES_PER_CELL=10, CELL_CENTERED=.TRUE., PART_ID='DRAG 5',  XB=1.01,1.02,0.0,1.0,0.0,1.0 /
-&INIT N_PARTICLES_PER_CELL=10, CELL_CENTERED=.TRUE., PART_ID='DRAG 10', XB=1.01,1.02,0.0,1.0,1.1,2.1 /
-&INIT N_PARTICLES_PER_CELL=10, CELL_CENTERED=.TRUE., PART_ID='DRAG 20', XB=1.01,1.02,0.0,1.0,2.2,3.2 /
-
-&DUMP FLUSH_FILE_BUFFERS=T, DT_DEVC=0.1 /
+&INIT N_PARTICLES_PER_CELL=10, CELL_CENTERED=.TRUE., PART_ID='DRAG 10', XB=1.01,1.02,0.0,1.0,1.1,2.1/
+&INIT N_PARTICLES_PER_CELL=10, CELL_CENTERED=.TRUE., PART_ID='DRAG 20', XB=1.01,1.02,0.0,1.0,2.2,3.2/
+&INIT N_PARTICLES_PER_CELL=10, CELL_CENTERED=.TRUE., PART_ID='DRAG 50', XB=1.01,1.02,0.0,1.0,3.3,4.3/
+&INIT N_PARTICLES_PER_CELL=10, CELL_CENTERED=.TRUE., PART_ID='DRAG 100', XB=1.01,1.02,0.0,1.0,4.4,5.4/
 
 &DEVC XYZ=0.50,0.5,0.50, QUANTITY='PRESSURE', ID='FDS 5'  /
-&DEVC XYZ=0.50,0.5,1.55, QUANTITY='PRESSURE', ID='FDS 10' /
-&DEVC XYZ=0.50,0.5,2.60, QUANTITY='PRESSURE', ID='FDS 20' /
+&DEVC XYZ=0.50,0.5,1.60, QUANTITY='PRESSURE', ID='FDS 10' /
+&DEVC XYZ=0.50,0.5,2.70, QUANTITY='PRESSURE', ID='FDS 20' /
+&DEVC XYZ=0.50,0.5,3.80, QUANTITY='PRESSURE', ID='FDS 50' /
+&DEVC XYZ=0.50,0.5,4.90, QUANTITY='PRESSURE', ID='FDS 100' /
 
 &TAIL /
+