Merge pull request #15712 from mcgratta/master

FDS Validation: Add puffing frequency

Author: mcgratta

Manuals/Bibliography/FDS_general.bib

@@ -7211,6 +7211,15 @@ @INPROCEEDINGS{Zukoski:IAFSS2
   publisher    = "Hemisphere Publishing Company",
 }
 
+@INBOOK{Zukoski:1995,
+  author       = {E.E. Zukoski},
+  editor       = {G. Cox},
+  title        = {{Combustion Fundamentals of Fire}},
+  chapter      = {{Properties of Fire Plumes}},
+  year         = {1995},
+  publisher    = {Academic Press, London}
+}
+
 @MISC{Colt:1,
   title        = {{Portsmouth Fire Test}},
   howpublished = {Colt Heating and Ventilation. Internal Report},

Manuals/FDS_Validation_Guide/Plume_Chapter.tex

@@ -984,6 +984,40 @@ \subsection{Flame Height Summary}
 \end{figure}
 
 
+\clearpage
+
+\section{Puffing Frequency}
+\label{Puffing Frequency}
+
+This section examines the ``puffing frequency'' of pool fires. Zukoski~\cite{Zukoski:1995} showed that the mean puffing frequency is inversely proportional to the square root of the burner diameter, $D$
+\be
+f = 0.50 \sqrt{g/D}
+\ee
+where $g$ is the gravitational acceleration. 
+
+\subsection{NIST Pool Fires}
+
+Figure~\ref{NIST_Pool_Fires_spectra} displays the predicted frequency spectra of the 30~cm and 37~cm NIST Pool Fires. The spectra are based on the simulated vertical velocity component, $w$, at a single point above the burner, recorded every time step. The vertical dashed line indicates the measured puffing frequency. The puffing frequency for the heptane was not measured.
+
+\begin{figure}[p]
+\begin{tabular*}{\textwidth}{l@{\extracolsep{\fill}}r}
+\includegraphics[height=2.15in]{SCRIPT_FIGURES/NIST_Pool_Fires/Acetone_frequency_spectrum} &
+\includegraphics[height=2.15in]{SCRIPT_FIGURES/NIST_Pool_Fires/Ethanol_frequency_spectrum} \\
+\includegraphics[height=2.15in]{SCRIPT_FIGURES/NIST_Pool_Fires/Heptane_frequency_spectrum} &
+\includegraphics[height=2.15in]{SCRIPT_FIGURES/NIST_Pool_Fires/Methane_frequency_spectrum} \\
+\includegraphics[height=2.15in]{SCRIPT_FIGURES/NIST_Pool_Fires/Methanol_frequency_spectrum} &
+\includegraphics[height=2.15in]{SCRIPT_FIGURES/NIST_Pool_Fires/Propane_20_frequency_spectrum} \\
+\includegraphics[height=2.15in]{SCRIPT_FIGURES/NIST_Pool_Fires/Propane_34_frequency_spectrum} &
+\includegraphics[height=2.15in]{SCRIPT_FIGURES/NIST_Pool_Fires/Propane_50_frequency_spectrum}
+\end{tabular*}
+\caption[Frequency spectra of the NIST Pool Fires]
+{Frequency spectra of the NIST Pool Fires with a vertical dashed line indicating the measured puffing frquency.}
+\label{NIST_Pool_Fires_spectra}
+\end{figure}
+
+
+
+
 
 \clearpage
 

Utilities/Python/FDS_validation_script.py

@@ -95,6 +95,7 @@ def safe_run(script_path):
 print("Memorial_Tunnel...");              safe_run("./scripts/Memorial_Tunnel.py")
 print("Memorial_Tunnel_2...");            safe_run("./scripts/Memorial_Tunnel_2.py")
 print("NIST_NRC_Parallel_Panels...");     safe_run("./scripts/NIST_NRC_Parallel_Panels.py")
+print("NIST_Pool_Fires...");              safe_run("./scripts/NIST_Pool_Fires.py")
 print("Sandia_Plumes...");                safe_run("./scripts/Sandia_Plumes.py")
 print("Sandia_Pools...");                 safe_run("./scripts/Sandia_Pools.py")
 print("Theobald_Hose_Stream...");         safe_run("./scripts/Theobald_Hose_Stream.py")

Utilities/Python/scripts/NIST_Pool_Fires.py

@@ -0,0 +1,62 @@
+
+import pandas as pd
+import numpy as np
+import matplotlib.pyplot as plt
+import fdsplotlib
+
+plot_style = fdsplotlib.get_plot_style('fds')
+
+outdir = '../../../out/NIST_Pool_Fires/'
+pltdir = '../../Manuals/FDS_Validation_Guide/SCRIPT_FIGURES/NIST_Pool_Fires/'
+
+chids = ['NIST_Acetone_Prescribed_0p5cm',
+         'NIST_Ethanol_Prescribed_0p5cm',
+         'NIST_Heptane_Prescribed_0p5cm',
+         'NIST_Methane_Prescribed_0p5cm',
+         'NIST_Methanol_Prescribed_0p5cm',
+         'NIST_Propane_20kW_Prescribed_0p5cm',
+         'NIST_Propane_34kW_Prescribed_0p5cm',
+         'NIST_Propane_50kW_Prescribed_0p5cm']
+
+fuel = ['Acetone','Ethanol','Heptane','Methane','Methanol','Propane 20 kW','Propane 34 kW','Propane 50 kW']
+label = ['Acetone','Ethanol','Heptane','Methane','Methanol','Propane_20','Propane_34','Propane_50']
+ideal = [2.45,2.41,-1,2.48,2.49,2.22,2.39,2.39]
+i = -1
+
+for chid in chids:
+
+    i = i + 1
+    git_file = outdir + chid + '_git.txt'
+    version_string = fdsplotlib.get_version_string(git_file)
+    
+    # Read CSV file, skipping the first two rows
+    df = pd.read_csv(outdir + chid + '_devc.csv', skiprows=20000, header=None)
+    
+    # Extract time and data columns
+    time = df.iloc[:, 0].values
+    data = df.iloc[:, 1].values
+    
+    # Calculate the sampling rate
+    dt = np.mean(np.diff(time))  # Average time step
+    sampling_rate = 1.0 / dt
+    
+    # Compute FFT
+    n = len(data)
+    fft_values = np.fft.fft(data)
+    fft_freq = np.fft.fftfreq(n, dt)
+    
+    # Get positive frequencies only
+    positive_freq_idx = fft_freq > 0
+    frequencies = fft_freq[positive_freq_idx]
+    magnitude = np.abs(fft_values[positive_freq_idx])
+    
+    # Create the frequency spectrum plot using plot_to_fig
+    fig = fdsplotlib.plot_to_fig(frequencies, magnitude, marker_style='k-',
+                                 x_label='Frequency (Hz)', y_label='Magnitude',
+                                 x_min=0, x_max=6, y_min=0,
+                                 revision_label=version_string,
+                                 plot_title=fuel[i])
+    fdsplotlib.plot_to_fig([ideal[i],ideal[i]],[0,100000], marker_style='k--', figure_handle=fig)
+    
+    fig.savefig(pltdir + label[i] + '_frequency_spectrum.pdf', format='pdf')
+