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mcgratta merged 1 commit into from
Nov 4, 2025
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FDS Verification: Misc fixes #15536

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7 changes: 4 additions & 3 deletions Manuals/FDS_User_Guide/FDS_User_Guide.tex
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Original file line number Diff line number Diff line change
Expand Up @@ -9140,7 +9140,8 @@ \section{Flux Limiters}
Central differencing & \ct{'CENTRAL'} \\
Godunov & \ct{'GODUNOV'} \\
Superbee (VLES, SVLES default) & \ct{'SUPERBEE'} \\
CHARM (DNS, LES default) & \ct{'CHARM'} \\
CHARM (DNS, LES default) & \ct{'CHARM'} \\
\hline
\end{tabular}
\end{table}

Expand Down Expand Up @@ -9171,9 +9172,9 @@ \subsection{Density}

The density of the gas has a natural lower bound of zero, but if the density in a cell decreases to nearly zero, the temperature would then increase to an extremely high value due to the equation of state. Thus, by default, the density is kept within the following range:
\be
\min \left( 0.1 \, \rho_\infty , \frac{2 \, p_\infty \, W_{\min}}{\R \, T_{\max}} \right) < \rho < \frac{2 \, p_\infty \, W_{\max}}{\R \, T_{\min}}
0.01 \; \mbox{kg/m$^3$} < \rho < 100 \; \mbox{kg/m$^3$}
\ee
where $W_{\min}$ and $W_{\max}$ are the minimum and maximum values of the molecular weight of the tracked gas species in units of g/mol, and $\R$ is the universal gas constant, 8314.5~J/(kmol$\cdot$K). $T_{\min}$ and $T_{\max}$ are described above. To override the limits of density, specify \ct{MINIMUM_DENSITY} and/or \ct{MAXIMUM_DENSITY} on the \ct{CLIP} line in units of kg/m$^3$.
To override the limits of density, specify \ct{MINIMUM_DENSITY} and/or \ct{MAXIMUM_DENSITY} on the \ct{CLIP} line in units of kg/m$^3$.

Clipping of density and mass fractions violates mass conservation, so it is preferable to avoid clipping if possible. As discussed in Sec.~\ref{info:Stability_Constraints}, the time step is set to adhere to the CFL constraints of the flow field. The proper \ct{DT} combined with flux limiters generally avoids the need for clipping. Beyond this, FDS then employs a mass redistribution scheme, as discussed in FDS Technical Guide~\cite{FDS_Math_Guide}. If this fails, there is yet one more attempt to avoid clipping---the time step is decreased by 10~\% ($\dt_{\mathrm{new}} = 0.9 \,\dt$) and the scalar transport equations are reiterated. This process is carried out a maximum of \ct{CLIP_DT_RESTRICTIONS_MAX} times; the default is 5. In some very extreme circumstances, this loop can drive the time step into numerical instability range ($\dt/\dt_{\mathrm{init}} < \mbox{\ct{LIMITING_DT_RATIO}}$). You can control the max number of time step restrictions by setting the parameter \ct{CLIP_DT_RESTRICTIONS_MAX} on the \ct{CLIP} line (set to 0 to bypass the algorithm altogether). The number of restrictions (if any) is noted in the \ct{CHID.out} file for a given time step.

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10 changes: 5 additions & 5 deletions Utilities/Matlab/FDS_verification_dataplot_inputs.csv
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Expand Up @@ -469,17 +469,17 @@ d,mass_heat_wall_device_test,Flowfields/mass_heat_wall_device_test_git.txt,Flowf
d,mass_heat_wall_device_test,Flowfields/mass_heat_wall_device_test_git.txt,Flowfields/mass_heat_wall_device_test_data.csv,2,3,Time,HF vent|HF open,Ideal Heat Flow Out|Ideal Heat Flow In,ko|ro,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Flowfields/mass_heat_wall_device_test_devc.csv,2,3,Time,HF vent|HF open,FDS Heat Flow Out|FDS Heat Flow In,k-|r-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Heat Flow (mass\_heat\_wall\_device\_test),Time (s),Heat Flow (kW),0,60,1,-500,500,1,no,0.05 0.90,East,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/wall_device_test_heatflow,Relative Error,end,0.01,Flowfields,r>,r,TeX
d,mass_heat_wall_device_test_2,Flowfields/mass_heat_wall_device_test_2_git.txt,Flowfields/mass_heat_wall_device_test_data.csv,2,3,Time,MF vent|MF open,Ideal Mass Flow Out|Ideal Mass Flow In,ko|ro,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Flowfields/mass_heat_wall_device_test_2_devc.csv,2,3,Time,MF vent|MF open,FDS Mass Flow Out|FDS Mass Flow In,k-|r-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Mass Flow (mass\_heat\_wall\_device\_test\_2),Time (s),Mass Flow (kg/s),0,60,1,-6,6,1,no,0.05 0.90,East,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/wall_device_test_massflow_2,Relative Error,end,0.01,Flowfields,r>,r,TeX
d,mass_heat_wall_device_test_2,Flowfields/mass_heat_wall_device_test_2_git.txt,Flowfields/mass_heat_wall_device_test_data.csv,2,3,Time,HF vent|HF open,Ideal Heat Flow Out|Ideal Heat Flow In,ko|ro,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Flowfields/mass_heat_wall_device_test_2_devc.csv,2,3,Time,HF vent|HF open,FDS Heat Flow Out|FDS Heat Flow In,k-|r-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Heat Flow (mass\_heat\_wall\_device\_test\_2),Time (s),Heat Flow (kW),0,60,1,-500,500,1,no,0.05 0.90,East,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/wall_device_test_heatflow_2,Relative Error,end,0.01,Flowfields,r>,r,TeX
d,methane_flame,Species/methane_flame_primitive_git.txt,Species/methane_flame_simple_devc.csv,2,3,Time,CO2|H2O|CO,CO2 simple|H2O simple|CO simple * 30,k|r|b,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species/methane_flame_lumpedprimitive.csv,2,3,Time,pCO2|pH2O|pCO|lCO2|lH2O|lCO,CO2 primitive|H2O primitive|CO primitive * 30|CO2 lumped|H2O lumped|CO lumped * 30,ko|rs|bd|kx|r+|b*,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species mass (simple v. primitive v. lumped),Time (s),Mass (kg),0,10,1,0,0.05,1,no,0.03 0.90,EastOutside,,1.4,linear,FDS_Verification_Guide/SCRIPT_FIGURES/methane_flame_reac_comp,Relative Error,end_1_1,1.00E-02,Species,mx,m,TeX
d,methane_flame,Species/methane_flame_primitive_2_git.txt,Species/methane_flame_primitive_2_devc.csv,2,3,Time,pCO2|pH2O,CO2 primitive|H2O primitive,k|r,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species/methane_flame_multilumped.csv,2,3,Time,lfCO2|lfH2O|loCO2|loH2O,CO2 lumped fuel|H2O lumped fuel|CO2 lumped oxidizer|H2O lumped oxidizer,ko|rs|bd|kx,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species mass (primitive v. lumped fuel v. lumped oxidizer),Time (s),Mass (kg),0,10,1,0,0.15,1,no,0.03 0.90,EastOutside,,1.4,linear,FDS_Verification_Guide/SCRIPT_FIGURES/methane_flame_lumped_comp,Relative Error,end_1_1,0.01,Species,mx,m,TeX
d,methane_flame,Species/methane_flame_simple_git.txt,Species/methane_flame_simple_devc.csv,2,3,Time,CO2|H2O|CO,CO2 simple|H2O simple|CO simple * 30,k|r|b,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species/methane_flame_simple_2_devc.csv,2,3,Time,CO2|H2O|CO,CO2 simple 2| H2O lumped 2 | CO lumped 2 * 30,ko|rs|bd,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species mass (simple v. simple 2),Time (s),Mass (kg),0,10,1,0,0.05,1,no,0.03 0.90,SouthEast,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/methane_flame_simp_comp,Relative Error,end,0.01,Species,mx,m,TeX
d,methane_flame,Species/methane_flame_primitive_git.txt,Species/methane_flame_simple_devc.csv,2,3,Time,CO2|H2O|CO,CO2 simple|H2O simple|CO simple * 30,k-|r-|b-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species/methane_flame_lumpedprimitive.csv,2,3,Time,pCO2|pH2O|pCO|lCO2|lH2O|lCO,CO2 primitive|H2O primitive|CO primitive * 30|CO2 lumped|H2O lumped|CO lumped * 30,ko|rs|bd|kx|r+|b*,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species mass (simple v. primitive v. lumped),Time (s),Mass (kg),0,10,1,0,0.05,1,no,0.03 0.90,EastOutside,,1.4,linear,FDS_Verification_Guide/SCRIPT_FIGURES/methane_flame_reac_comp,Relative Error,end_1_1,1.00E-02,Species,mx,m,TeX
d,methane_flame,Species/methane_flame_primitive_2_git.txt,Species/methane_flame_primitive_2_devc.csv,2,3,Time,pCO2|pH2O,CO2 primitive|H2O primitive,k-|r-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species/methane_flame_multilumped.csv,2,3,Time,lfCO2|lfH2O|loCO2|loH2O,CO2 lumped fuel|H2O lumped fuel|CO2 lumped oxidizer|H2O lumped oxidizer,ko|rs|bd|kx,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species mass (primitive v. lumped fuel v. lumped oxidizer),Time (s),Mass (kg),0,10,1,0,0.15,1,no,0.03 0.90,EastOutside,,1.4,linear,FDS_Verification_Guide/SCRIPT_FIGURES/methane_flame_lumped_comp,Relative Error,end_1_1,0.01,Species,mx,m,TeX
d,methane_flame,Species/methane_flame_simple_git.txt,Species/methane_flame_simple_devc.csv,2,3,Time,CO2|H2O|CO,CO2 simple|H2O simple|CO simple * 30,k-|r-|b-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species/methane_flame_simple_2_devc.csv,2,3,Time,CO2|H2O|CO,CO2 simple 2| H2O lumped 2 | CO lumped 2 * 30,ko|rs|bd,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species mass (simple v. simple 2),Time (s),Mass (kg),0,10,1,0,0.05,1,no,0.03 0.90,SouthEast,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/methane_flame_simp_comp,Relative Error,end,0.01,Species,mx,m,TeX
d,multiple_reac_hrrpua,Species/multiple_reac_hrrpua_git.txt,Species/multiple_reac_hrrpua.csv,1,2,Time,CH4|C2H6|C3H8|CHO|H2plusC7H8,Ideal CH4|Ideal C2H6|Ideal C3H8|Ideal CHO|Ideal H2+C7H8,ko|ro|bo|mo|go,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species/multiple_reac_hrrpua_hrr.csv,2,3,Time,MLR_METHANE|MLR_ETHANE|MLR_PROPANE|MLR_MYFUEL|MLR_MYFUEL2,FDS CH4|FDS C2H6|FDS C3H8|FDS CHO|FDS H2+C7H8,k-|r-|b-|m-|g-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species Mass Flux,Time (s),Mass Flux (kg/m²/s),0,5,1,0,0.001,1,no,0.03 0.90,East,,1,linear,FDS_User_Guide/SCRIPT_FIGURES/multiple_reac_hrrpua,Relative Error,end,0.01,Species,yx,y,TeX
d,multiple_reac_n_simple,Species/multiple_reac_n_simple_git.txt,Species/multiple_reac_n_simple.csv,1,2,Time,CH4_CO|CH4_H2,Ideal CO|Ideal H2,ko|ro,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species/multiple_reac_n_simple_devc.csv,2,3,Time,CH4_CO|CH4_H2,FDS CO|FDS H2,k-|r-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,CH4 Species Mass,Time (s),Mass (kg),0,0.0001,1,0,0.006,1,no,0.03 0.90,East,,1,linear,FDS_User_Guide/SCRIPT_FIGURES/multiple_reac_n_simple_CH4,Relative Error,end,0.01,Species,yd,y,TeX
d,multiple_reac_n_simple,Species/multiple_reac_n_simple_git.txt,Species/multiple_reac_n_simple.csv,1,2,Time,C3H8_CO|C3H8_H2O,Ideal CO|Ideal H2O,ko|ro,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species/multiple_reac_n_simple_devc.csv,2,3,Time,C3H8_CO|C3H8_H2O,FDS CO|FDS H2O,k-|r-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,C3H8 Species Mass,Time (s),Mass (kg),0,0.0001,1,0,0.025,1,no,0.03 0.90,East,,1,linear,FDS_User_Guide/SCRIPT_FIGURES/multiple_reac_n_simple_C3H8,Relative Error,end,0.01,Species,ys,y,TeX
d,multiple_reac_n_simple,Species/multiple_reac_n_simple_git.txt,Species/multiple_reac_n_simple.csv,1,2,Time,C2H6_CO|C2H6_H2,Ideal CO|Ideal H2O,ko|ro,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Species/multiple_reac_n_simple_devc.csv,2,3,Time,C2H6_CO|C2H6_H2,FDS CO|FDS H2,k-|r-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,C2H6 Species Mass,Time (s),Mass (kg),0,0.0001,1,0,0.035,1,no,0.03 0.90,East,,1,linear,FDS_User_Guide/SCRIPT_FIGURES/multiple_reac_n_simple_C2H6,Relative Error,end,0.01,Species,yd,y,TeX
d,methanol_evaporation,Pyrolysis/methanol_evaporation_git.txt,Pyrolysis/methanol_evaporation_devc.csv,2,3,Time,mdot,Computed Evaporation Rate (mdot),k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Pyrolysis/methanol_evaporation_devc.csv,2,3,Time,mdot2,Ideal Evaporation Rate (mdot2),k--,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Liquid Evaporation (methanol\_evaporation),Time (min),Mass Loss Rate (kg/m²/s),0,6,60,0,0.025,1,no,0.05 0.90,SouthEast,,1,linear,FDS_User_Guide/SCRIPT_FIGURES/methanol_evaporation_mdot,Relative Error,end,0.02,Pyrolysis,mx,m,TeX
d,methanol_evaporation,Pyrolysis/methanol_evaporation_git.txt,Pyrolysis/methanol_evaporation.csv,1,2,Time,Tb,Measured Boiling Temperature (Tb),ko,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Pyrolysis/methanol_evaporation_devc.csv,2,3,Time,Tsurf,Surface Temperature (Tsurf),k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Liquid Evaporation (methanol\_evaporation),Time (min),Temperature (°C),0,6,60,0,100,1,no,0.05 0.90,SouthEast,,1,linear,FDS_User_Guide/SCRIPT_FIGURES/methanol_evaporation_temp,Relative Error,end,0.015,Pyrolysis,mx,m,TeX
d,MO_velocity_profile_stable,Atmospheric_Effects/MO_velocity_profile_stable_git.txt,Atmospheric_Effects/MO_velocity_profile_stable.csv,1,2,z (m),u (m/s),MO profile,k,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Atmospheric_Effects/MO_velocity_profile_stable_line.csv,2,3,z,u,FDS profile,k--,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Monin-Obukhov profile stable,z (m),u (m/s),0,32,1,0,10,1,no,0.03 0.90,SouthEast,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/MO_velocity_profile_stable,Relative Error,area,0.05,Flowfields,r>,r,TeX
d,MO_velocity_profile_unstable,Atmospheric_Effects/MO_velocity_profile_unstable_git.txt,Atmospheric_Effects/MO_velocity_profile_unstable.csv,1,2,z (m),u (m/s),MO profile,k,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Atmospheric_Effects/MO_velocity_profile_unstable_line.csv,2,3,z,u,FDS profile,k--,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Monin-Obukhov profile unstable,z (m),u (m/s),0,32,1,0,15,1,no,0.03 0.90,SouthEast,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/MO_velocity_profile_unstable,Relative Error,area,0.05,Flowfields,r>,r,TeX
d,MO_velocity_profile_stable,Atmospheric_Effects/MO_velocity_profile_stable_git.txt,Atmospheric_Effects/MO_velocity_profile_stable.csv,1,2,z (m),u (m/s),MO profile,k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Atmospheric_Effects/MO_velocity_profile_stable_line.csv,2,3,z,u,FDS profile,k--,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Monin-Obukhov profile stable,z (m),u (m/s),0,32,1,0,10,1,no,0.03 0.90,SouthEast,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/MO_velocity_profile_stable,Relative Error,area,0.05,Flowfields,r>,r,TeX
d,MO_velocity_profile_unstable,Atmospheric_Effects/MO_velocity_profile_unstable_git.txt,Atmospheric_Effects/MO_velocity_profile_unstable.csv,1,2,z (m),u (m/s),MO profile,k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Atmospheric_Effects/MO_velocity_profile_unstable_line.csv,2,3,z,u,FDS profile,k--,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Monin-Obukhov profile unstable,z (m),u (m/s),0,32,1,0,15,1,no,0.03 0.90,SouthEast,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/MO_velocity_profile_unstable,Relative Error,area,0.05,Flowfields,r>,r,TeX
d,Morvan_TGA,WUI/Morvan_TGA_git.txt,WUI/Morvan_Data_Mass.csv,1,2,T (C),Normalized Mass (M/M0),Exp (Morvan 2004),k^,0,100000,,0,100000,-1.00E+09,1.00E+09,0,WUI/Morvan_TGA_tga.csv,2,3,Temp,Total Mass,FDS TGA (Total Mass),k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Morvan TGA; 1.6 °C/min,Temperature (°C),Normalized Mass,0,700,1,0,1.2,1,no,0.05 0.90,East,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/Morvan_TGA_Total_Mass,N/A,mean,0,Needle TGA,kd,k,TeX
d,Morvan_TGA,WUI/Morvan_TGA_git.txt,WUI/Morvan_Data_SG_Deriv.csv,1,2,T (C),normalized Savitsky-Golay derivative,SG deriv (Morvan 2004),k--,0,100000,,0,100000,-1.00E+09,1.00E+09,0,WUI/Morvan_TGA_tga.csv,2,3,Temp,Total MLR,FDS TGA (Total MLR),k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Morvan TGA; 1.6 °C/min,Temperature (°C),Mass Loss Rate (1/s),0,700,1,0,1.50E-04,1,no,0.05 0.90,East,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/Morvan_TGA_Total_MLR,N/A,mean,0,Needle TGA,kd,k,TeX
d,Morvan_TGA,WUI/Morvan_TGA_2_git.txt,WUI/Morvan_Data_Mass.csv,1,2,T (C),Normalized Mass (M/M0),Exp (Morvan 2004),k^,0,100000,,0,100000,-1.00E+09,1.00E+09,0,WUI/Morvan_TGA_2_tga.csv,2,3,Temp,Total Mass,FDS TGA (Total Mass),k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Morvan TGA; 1.6 °C/min,Temperature (°C),Normalized Mass,0,700,1,0,1.2,1,no,0.05 0.90,East,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/Morvan_TGA_2_Total_Mass,N/A,mean,0,Needle TGA,kd,k,TeX
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