Skip to content

FDS Manuals Verification: Make figure height 2.2in #15597

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
cxp484 merged 2 commits into from
Nov 19, 2025
Merged

FDS Manuals Verification: Make figure height 2.2in #15597

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
5f9e2d5
FDS Manuals Verification: Make figure height 2.2in
cxp484 Nov 19, 2025
a30a220
FDS Manuals Verification: Make figure height 2.2in
cxp484 Nov 19, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
32 changes: 20 additions & 12 deletions Manuals/FDS_Verification_Guide/FDS_Verification_Guide.tex
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3999,29 +3999,37 @@ \section{Mixing with detailed chemistry (\ct{edc\_mixing\_cvode})}

This implementation has been validated against results obtained using Cantera~\cite{cantera:2023}. Note that Cantera does not provide a direct method to solve the coupled mixing-chemistry ODE system as done here in FDS; therefore, in Cantera an operator splitting approach was employed, where mixing and chemistry are handled sequentially. Specifically, within each CFD timestep (0.1 s), substeps for chemistry calculations in Cantera are kept sufficiently small (0.0001 s) to resolve the fast dynamics. All comparisons are carried out using the GRI-Mech 3.0 chemical mechanism~\cite{gri3:1999}.

Figure~\ref{fig:edc_mixing_cvode_onecfdstep_vary_zeta0} presents comparisons of temperature and OH mass fraction between FDS and Cantera within a single CFD timestep for five constant-volume ignition delay cases, with varying initial unmixed fractions \(\zeta_0 = 1.0, 0.75, 0.5, 0.25, 0.0\).
Figures~\ref{fig:edc_mixing_cvode_onecfdstep_vary_zeta0_1} and~\ref{fig:edc_mixing_cvode_onecfdstep_vary_zeta0_2} presents comparisons of temperature and OH mass fraction between FDS and Cantera within a single CFD timestep for five constant-volume ignition delay cases, with varying initial unmixed fractions \(\zeta_0 = 1.0, 0.75, 0.5, 0.25, 0.0\).

Figure~\ref{fig:edc_mixing_cvode_multicfdstep_vary_zeta0} shows similar comparisons over multiple CFD timesteps for the same ignition delay cases and initial unmixed fractions. These results also verify that elemental mass is conserved throughout the entire process.

Finally, Figure~\ref{fig:edc_mixing_cvode_onecfdstep_vary_taumix} compares temperature and OH mass fraction for a single CFD timestep across five cases with varying mixing times \(\tau_{\text{mix}} = 0.1, 0.01, 0.001, 0.0001, 0.00001\) s. As the mixing time decreases, the solution becomes independent of \(\tau_{\text{mix}}\), approaching the well-stirred reactor limit corresponding to (\(\zeta_0 = 0.0\)).

\begin{figure}[p]
\begin{tabular*}{\textwidth}{lr}
\includegraphics[height=1.6in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta1p0_TMP} &
\includegraphics[height=1.6in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta1p0_OH} \\
\includegraphics[height=1.6in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p75_TMP} &
\includegraphics[height=1.6in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p75_OH} \\
\includegraphics[height=1.6in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p5_TMP} &
\includegraphics[height=1.6in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p5_OH} \\
\includegraphics[height=1.6in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p25_TMP} &
\includegraphics[height=1.6in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p25_OH} \\
\includegraphics[height=1.6in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p0_TMP} &
\includegraphics[height=1.6in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p0_OH}
\includegraphics[height=2.2in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta1p0_TMP} &
\includegraphics[height=2.2in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta1p0_OH} \\
\includegraphics[height=2.2in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p75_TMP} &
\includegraphics[height=2.2in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p75_OH} \\
\includegraphics[height=2.2in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p5_TMP} &
\includegraphics[height=2.2in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p5_OH} \\
\includegraphics[height=2.2in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p25_TMP} &
\includegraphics[height=2.2in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p25_OH}
\end{tabular*}
\caption[Results of the \ct{edc\_mixing\_cvode} test cases]{Comparison of CVODE substeps for a single CFD step of 0.1 s, showing the effect of varying the initial unmixed fraction between FDS and Cantera. The simulation uses the Methane GRI mechanism with an equivalence ratio of 0.6, a mixing time of 0.01 s, and an initial temperature of 1200 K.}
\label{fig:edc_mixing_cvode_onecfdstep_vary_zeta0}
\label{fig:edc_mixing_cvode_onecfdstep_vary_zeta0_1}
\end{figure}

\begin{figure}[p]
\begin{tabular*}{\textwidth}{lr}
\includegraphics[height=2.2in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p0_TMP} &
\includegraphics[height=2.2in]{SCRIPT_FIGURES/EDC_OneCFDStep_Methane_grimech30_Zeta0p0_OH}
\end{tabular*}
\caption[Results of the \ct{edc\_mixing\_cvode} test cases]{Continued from Figure~\ref{fig:edc_mixing_cvode_onecfdstep_vary_zeta0_1}.}
\label{fig:edc_mixing_cvode_onecfdstep_vary_zeta0_2}
\end{figure}


\begin{figure}[p]
\begin{tabular*}{\textwidth}{lcr}
\includegraphics[height=1.6in,width=0.32\textwidth]{SCRIPT_FIGURES/EDC_MultiCFDStep_Methane_grimech30_Zeta1p0_TMP} &
Expand Down