firemodels · drjfloyd · Jun 2, 2025 · Jun 2, 2025
diff --git a/Manuals/FDS_User_Guide/FDS_User_Guide.tex b/Manuals/FDS_User_Guide/FDS_User_Guide.tex
@@ -3998,6 +3998,46 @@ \subsection{Specified Flow vs. Unspecified Flow}
 
 In the second approach, one or more ducts have flows that are not specified, in this case FDS must solve for the pressures at either end of the duct to determine the flow through the duct. As one example, if a tee has three ducts and only one of the ducts has a specified flow, then FDS will use the relative pressure drops along the two other ducts to determine the flow. If no \ct{LOSS} inputs are given, then FDS may not correctly solve for the flow. As another example, losses in the HVAC network limit how quickly flow in the ducts can change over time. If there is a single duct connecting two rooms with no \ct{LOSS} inputs given, then small pressure changes can lead to large changes in duct velocity and increase the risk of a numerical instability. If you specify an HVAC network where flow is being solved for by FDS, then you must provided \ct{LOSS} inputs for each possible flow path. FDS will perform a check at startup and return an error message if it finds insufficient losses have been specified; however, this check may not discover all cases.
 
+\subsection{HVAC and Unstructured Geometry}
+\label{info:hvac_geom}
+
+Assigning either a normal HVAC node or a localized leakage HVAC to a GEOM is done using \ct{SURF}. Using the simple example from Section~\ref{info:GEOM_Basics}, an HVAC node named \ct{'MY NODE'} is assigned to the first face by defining a \ct{SURF} with \ct{NODE_ID='MY NODE'}. No other boundary conditions should be set on the \ct{SURF} other than a color or texture. On the node \ct{HVAC} input set \ct{GEOM=T} to indicate FDS needs to look for a \ct{GEOM} and not a \ct{VENT} for the node:
+
+\begin{lstlisting}
+	&SURF ID='NODE SURF',NODE_ID='MY NODE'/
+	&GEOM ID='My Solid'
+	SURF_ID='NODE SURF','INERT'
+	VERTS= -1.0, -1.0,  0.0,
+	1.0, -1.0,  0.0,
+	0.0,  1.0,  0.0,
+	0.0,  0.0,  1.0,
+	FACES= 1,3,2, 2,
+	1,4,3, 1,
+	3,4,2, 1,
+	2,4,1, 0 /
+	&HVAC ID='MY NODE',TYPE_ID='NODE',GEOM=T,..../
+\end{lstlisting}
+
+The \ct{SURF} input \ct{NODE_ID} can only be applied to complex geometry. It cannot be used for \ct{OBST} or \ct{VENT}. While more than one \ct{GEOM} and more than one face of a \ct{GEOM} can use the same node, the same node cannot be shared by both a \ct{VENT} and a \ct{GEOM}. 
+
+To apply localized leakage to \ct{GEOM}, the process is similar. \ct{NODE_ID} on \ct{SURF} is still used to link faces of \ct{GEOM} to the localized leakage. The input for the localized leakage changes slightly. The inputs \ct{VENT_ID} and \ct{VENT2_ID} use \ct{GEOM} and \ct{GEOM2} to determine if the respective \ct{ID} is attached to a \ct{VENT} or a \ct{GEOM}.  For example, to attach the second vent for a localized leakage path:
+
+\begin{lstlisting}
+	&SURF ID='LEAK SURF',NODE_ID='LEAK OUT'/
+	&GEOM ID='My Solid'
+	SURF_ID='LEAK SURF','INERT'
+	VERTS= -1.0, -1.0,  0.0,
+	1.0, -1.0,  0.0,
+	0.0,  1.0,  0.0,
+	0.0,  0.0,  1.0,
+	FACES= 1,3,2, 2,
+	1,4,3, 1,
+	3,4,2, 1,
+	2,4,1, 0 /
+	&HVAC ID='MY LEAK',TYPE_ID='LEAK',VENT_ID='LEAK IN',VENT2_ID='LEAK OUT',GEOM2=T,AREA=0.01/
+\end{lstlisting}
+
+Here the use of \ct{GEOM2=T} indicates that \ct{VENT2_ID} is a \ct{NODE_ID} on \ct{SURF}.
 
 \newpage
 
@@ -12413,6 +12453,8 @@ \section{\texorpdfstring{{\tt HVAC}}{HVAC} (HVAC System Definition)}
 \ct{FAN_ID}                 & Character     & Section~\ref{info:HVACduct}                                              &               &                \\ \hline
 \ct{FILTER_ID}              & Character     & Section~\ref{info:HVACnode}                                              &               &                \\ \hline
 \ct{FIXED_Q}                & Real          & Section~\ref{info:HVACaircoil}                                           & kW            &                \\ \hline
+\ct{GEOM}                   & Logical       & Section~\ref{info:hvac_geom}                                             &               & \ct{F}        \\ \hline
+\ct{GEOM2}                  & Logical       & Section~\ref{info:hvac_geom}                                             &               & \ct{F}        \\ \hline
 \ct{ID}                      & Character     & Section~\ref{info:HVAC}                                                  &               &                \\ \hline
 \ct{LEAK_ENTHALPY}          & Logical       & Section~\ref{info:local_leakage}                                         &               & \ct{F}        \\ \hline
 \ct{LEAK_PRESSURE_EXPONENT}& Real          & Section~\ref{info:Leaks}                                                 &               & 0.5            \\ \hline
@@ -13546,6 +13588,7 @@ \section{\texorpdfstring{{\tt SURF}}{SURF} (Surface Properties)}
 \ct{NEAR_WALL_TURBULENCE_MODEL}                       & Character       & Section~\ref{info:LES}                    &                     &                         \\ \hline
 \ct{NET_HEAT_FLUX}                                     & Real            & Section~\ref{info:convection}             & \unit{kW/m^2}            &                         \\ \hline
 \ct{NO_SLIP}                                            & Logical         & Section~\ref{info:WALL_MODEL}             &                     & \ct{F}                 \\ \hline
+\ct{NODE_ID}                                          & Character          & Section~\ref{info:hvac_geom}              &                     &                       \\ \hline
 \ct{NPPC}                                                & Integer         & Section~\ref{info:particle_flux}          &                     & 1                       \\ \hline
 \ct{NUSSELT_C0}                                         & Real            & Section~\ref{info:convection}             &                     &                         \\ \hline
 \ct{NUSSELT_C1}                                         & Real            & Section~\ref{info:convection}             &                     &                         \\ \hline

diff --git a/Manuals/FDS_Verification_Guide/FDS_Verification_Guide.tex b/Manuals/FDS_Verification_Guide/FDS_Verification_Guide.tex
@@ -6903,7 +6903,7 @@ \subsection{Leak Pressure Exponent (\texorpdfstring{\ct{HVAC\_leak\_exponent}}{H
 
 The first verification case involves three 1000~m$^3$ compartments that have 0.01~m$^2$ of leakage to the ambient. Each compartment is supplied with 0.16~m$^3$/s of inlet flow. The first compartment has the default values for the exponent and reference pressure, the second changes the exponent to 0.6, and the third third changes exponent and the reference pressure respectively to 0.6 and 10~Pa. The expected leakage velocities for these conditions are 160~m/s, 11.8~m/s, and 12.8~m/s. Note in the left plot of Fig.~\ref{leak_exponent_fig} that the velocities are negative because the FDS output for the leakage velocity is from the lower numbered pressure zone (in this case ambient) to the higher number (inside the compartment). Negative velocity indicates flow from inside to outside as expected.
 
-The second case involves a steel enclosure with four localized leaks, two near the bottom and two near the top. The air flow into the compartment is ramped up slowly, and the right hand plot of Fig.~\ref{leak_exponent_fig} shows the ideal and predicted relationship between the volume flow and compartment pressure. In this case, $C_{\rm d}=0.61$, $n=0.6$, $\Delta p_{\rm ref}=1$~Pa, and $A_{\rm L,ref}=0.18$ at each of the four ``cracks.''
+The second case involves a steel e	nclosure with four localized leaks, two near the bottom and two near the top. The air flow into the compartment is ramped up slowly, and the right hand plot of Fig.~\ref{leak_exponent_fig} shows the ideal and predicted relationship between the volume flow and compartment pressure. In this case, $C_{\rm d}=0.61$, $n=0.6$, $\Delta p_{\rm ref}=1$~Pa, and $A_{\rm L,ref}=0.18$ at each of the four ``cracks.''
 
 \begin{figure}[ht]
 \includegraphics[height=2.2in]{SCRIPT_FIGURES/HVAC_leak_exponent}
@@ -6914,6 +6914,23 @@ \subsection{Leak Pressure Exponent (\texorpdfstring{\ct{HVAC\_leak\_exponent}}{H
 
 \FloatBarrier
 
+\section{Complex Geometry (\texorpdfstring{\ct{HVAC\_geom} and \ct{leak\_geom}} {HVAC\_geom and leak\_geom})}
+Two verification cases demonstrate the usage of HVAC for complex geometry.
+
+\label{HVAC_geom}
+In the first verification case (\ct{HVAC\_geom}), two, sealed, 1~m$^3$ compartments are separated by a common wall. An HVAC duct defined with \ct{GEOM} connects the two compartments and is given a duct velocity of 2~m/s. Two meshes are defined that divide the compartments along their centerline such that the \ct{GEOM} duct lies in each mesh. HVAC ducts are added to connect the other two ends of the compartments to ambient. The ducts have the same area as the \ct{GEOM} duct. At steady-state, all duct velocities should be the same.
+
+\label{leak_geom}
+In the second verification case (\ct{leak\_geom}), three, sealed, 1~m$^3$ compartments are defined in a row, separated by common walls. The left domain boundary is \ct{OPEN} with one grid cell before the start of the left compartment. The left side of the left compartment has a leak path that is a \ct{VENT} on the \ct{OPEN} side and a \ct{GEOM} inside the compartment. It is defined as four grid cells and given the leak area of a single grid cell. The right side of the left compartment has two leak paths connecting to the left side of the middle compartment. One path is defined with two \ct{VENT} inputs and the other with two \ct{GEOM} inputs. These are each defined with two grid cells and given half of the area of the first leak path. The right side of the middle compartment is connected to the left side of the right compartment with a leak path that is a \ct{GEOM} in the middle compartment and a \ct{VENT} in the right. It has the size and leak area as the first leak path. Combined these leak paths represent all combinations of \ct{VENT} and \ct{GEOM}. The right side of the right compartment has a single grid cell exhaust \ct{VENT}. At steady-state all four leak paths should have the same velocity.
+
+\begin{figure}[ht]
+	\includegraphics[height=2.2in]{SCRIPT_FIGURES/HVAC_geom}
+	\includegraphics[height=2.2in]{SCRIPT_FIGURES/leak_geom}
+	\caption[The HVAC + complex geometry cases]{(Left) Results of the \ct{HVAC\_geom} case. (Right) Results of the \ct{leak\_geom} case.}
+	\label{leak_exponent_fig}
+\end{figure}
+
+\FloatBarrier
 
 \section{ASHRAE Sample Problem 7\\(\texorpdfstring{\ct{ashrae\_7\_fixed\_flow}}{ashrae\_7\_fixed\_flow}, \texorpdfstring{\ct{ashrae\_7\_quadratic}}{ashrae\_7\_quadratic}, \texorpdfstring{\ct{ashrae\_7\_table}}{ashrae\_7\_table})}
 \label{ashrae7}

diff --git a/Utilities/Matlab/FDS_verification_dataplot_inputs.csv b/Utilities/Matlab/FDS_verification_dataplot_inputs.csv
@@ -377,6 +377,8 @@ d,HVAC_mass_transport_energy,HVAC/HVAC_mass_transport_energy_git.txt,HVAC/HVAC_m
 d,HVAC_mass_transport_energy,HVAC/HVAC_mass_transport_energy_git.txt,HVAC/HVAC_mass_transport_energy_ideal.csv,1,2,Time,Ideal Delta P,Ideal \Delta p,ko,0,100000,,0,100000,-1.00E+09,1.00E+09,0,HVAC/HVAC_mass_transport_energy_devc.csv,2,3,Time,FDS Delta P,FDS \Delta p,k-,0,100000,,20,40,-1.00E+09,1.00E+09,0,Pressure difference (HVAC\_mass\_transport\_energy),Time (s),Pressure (Pa),0,40,1,0.6,1.2,1,no,0.05 0.90,SouthEast,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/HVAC_mass_transport_energy_p,Relative Error,mean,0.01,HVAC,kd,k,TeX
 d,HVAC_tee_loss_1,HVAC/HVAC_tee_loss_1_git.txt,HVAC/HVAC_flow_loss_ideal.csv,1,2,Time,Ideal 1 m/s|Ideal 2 m/s|Ideal 3 m/s,Ideal 1 m/s|Ideal 2 m/s|Ideal 3 m/s,ro|bo|ko,0,100000,,0,100000,-1.00E+09,1.00E+09,0,HVAC/HVAC_tee_loss_1_devc.csv,2,3,Time,FDS 1 m/s duct|FDS 2 m/s duct|FDS 3 m/s duct,FDS 1 m/s|FDS 2 m/s|FDS 3 m/s,r-|b-|k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Velocities (HVAC\_tee\_loss\_1),Time (s),Velocity (m/s),0,10,1,0,5,1,no,0.40 0.90,NorthWest,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/HVAC_tee_loss_1,Relative Error,end,0.01,HVAC,kd,k,TeX
 d,HVAC_tee_loss_2,HVAC/HVAC_tee_loss_2_git.txt,HVAC/HVAC_tee_loss_2_ideal.csv,1,2,Time,Ideal 1.5 m/s A|Ideal 1.5 m/s B|Ideal 3 m/s,Ideal 1.5 m/s A|Ideal 1.5 m/s B|Ideal 3 m/s,ro|bo|ko,0,100000,,0,100000,-1.00E+09,1.00E+09,0,HVAC/HVAC_tee_loss_2_devc.csv,2,3,Time,E 1|E 2|S 1,FDS 1.5 m/s A|FDS 1.5 m/s B|FDS 3 m/s,r-|b-|k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Velocities (HVAC\_tee\_loss\_2),Time (s),Velocity (m/s),0,10,1,0,5,1,no,0.40 0.90,NorthWest,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/HVAC_tee_loss_2,Relative Error,end,0.01,HVAC,kd,k,TeX
+d,leak_geom,HVAC/leak_geom_git.txt,HVAC/leak_geom.csv,1,2,Time,V,Ideal,ro,0,100000,,0,100000,-1.00E+09,1.00E+09,0,HVAC/leak_geom_devc.csv,2,3,Time,L|C|C V|R,FDS Left|FDS Geom Center|FDS Vent Center|FDS Right,r-|b-|k-|g-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Velocities (HVAC\_tee\_loss\_2),Time (s),Velocity (m/s),0,5,1,0,0.2,1,no,0.40 0.90,NorthWest,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/leak_geom,Relative Error,end,0.01,HVAC,kd,k,TeX
+d,HVAC_geom,HVAC/HVAC_geom_git.txt,HVAC/HVAC_geom.csv,1,2,Time,V,Ideal,ro,0,100000,,0,100000,-1.00E+09,1.00E+09,0,HVAC/HVAC_geom_devc.csv,2,3,Time,L|LR|R,FDS Left In|FDS Left to Right |FDS Right Out,r-|b-|k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Velocities (HVAC\_tee\_loss\_2),Time (s),Velocity (m/s),0,5,1,0,3,1,no,0.40 0.90,NorthWest,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/HVAC_geom,Relative Error,end,0.01,HVAC,kd,k,TeX
 d,ignition_delay,Chemistry/ign_delay_Methane_grimech30_T900K_Phi0p6_cat_git.txt,Chemistry/cantera_ignition_delay.csv,1,2,Time1,TMP1,Cantera,ko,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Chemistry/ign_delay_Methane_grimech30_T900K_Phi0p6_cat_devc.csv,2,3,Time,TMP,FDS,b-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,ignition\_delay; T=626.85 °C,Time (s),Temperature (°C),0,10,1,550,3000,1,no,0.05 0.90,NorthEast,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/ign_delay_Methane_grimech30_900_0p6_TMP,Relative Error,area,0.02,Chemistry,b*,b,TeX
 d,ignition_delay,Chemistry/ign_delay_Methane_grimech30_T900K_Phi0p6_cat_git.txt,Chemistry/cantera_ignition_delay.csv,1,2,Time1,OH1,Cantera,ko,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Chemistry/ign_delay_Methane_grimech30_T900K_Phi0p6_cat_devc.csv,2,3,Time,OH,FDS,b-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,ignition\_delay; T=626.85 °C,Time (s),OH Mass Fraction,0,10,1,0,0.02,1,no,0.05 0.90,NorthEast,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/ign_delay_Methane_grimech30_900_0p6_OH,Relative Error,area,0.02,Chemistry,b*,b,TeX
 d,ignition_delay,Chemistry/ign_delay_Methane_grimech30_T1000K_Phi0p6_cat_git.txt,Chemistry/cantera_ignition_delay.csv,1,2,Time2,TMP2,Cantera,ko,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Chemistry/ign_delay_Methane_grimech30_T1000K_Phi0p6_cat_devc.csv,2,3,Time,TMP,FDS,b-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,ignition\_delay; T=726.85 °C,Time (s),Temperature (°C),0,2,1,550,3000,1,no,0.05 0.90,NorthEast,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/ign_delay_Methane_grimech30_1000_0p6_TMP,Relative Error,area,0.02,Chemistry,b*,b,TeX
@@ -817,4 +819,4 @@ f,anca-couce,Pyrolysis/anca-couce-fig2_2p5K_git.txt,Pyrolysis/Anca-Couce-fig1.cs
 f,anca-couce,Pyrolysis/anca-couce-fig2_2p5K_git.txt,Pyrolysis/Anca-Couce-fig1.csv,1,2,2.5K/min TMP,2.5K/min MLR,blank,blank,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Pyrolysis/anca-couce-fig2_2p5K_cat_tga.csv,2,3,Temp,LIGNIN MLR,LIGNIN,k:,0,100000,,0,100000,-1.00E+09,1.00E+09,0,0% O_2 (3C Wood Pyrolysis),Temperature (°C),Normalized Mass Loss Rate (1/s),200,550,1,0,3.20E-03,1,no,0.05 0.90,East,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/anca_couce_fig2_2p5K,N/A,max,0.1,pine wood TGA,kd,k,TeX
 s,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
 g,sphere_leak,Complex_Geometry/sphere_leak_git.txt,Complex_Geometry/sphere_leak.csv,1,2,Time,Pressure,Exact,ko,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Complex_Geometry/sphere_leak_devc.csv,2,3,Time,Pressure,FDS,k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Pressure Rise (sphere\_leak),Time (s),Pressure (Pa),0,100,1,0,5000,1,no,0.05 0.90,SouthEast,,1,linear,FDS_User_Guide/SCRIPT_FIGURES/sphere_leak,Relative Error,max,0.05,Pressure Effects,k+,k,TeX
-d,sphere_radiate,Complex_Geometry/sphere_radiate_git.txt,Complex_Geometry/sphere_radiate.csv,1,2,Time,HF,Exact,ko,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Complex_Geometry/sphere_radiate_devc.csv,2,3,Time,HF1,FDS,k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Heat Flux (sphere\_radiate),Time (s),Heat Flux (kW/m²),0,0.01,1,0,8,1,no,0.05 0.90,SouthEast,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/sphere_radiate,Relative Error,max,0.07,Radiation,bs,b,TeX
+d,sphere_radiate,Complex_Geometry/sphere_radiate_git.txt,Complex_Geometry/sphere_radiate.csv,1,2,Time,HF,Exact,ko,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Complex_Geometry/sphere_radiate_devc.csv,2,3,Time,HF1,FDS,k-,0,100000,,0,100000,-1.00E+09,1.00E+09,0,Heat Flux (sphere\_radiate),Time (s),Heat Flux (kW/m²),0,0.01,1,0,8,1,no,0.05 0.90,SouthEast,,1,linear,FDS_Verification_Guide/SCRIPT_FIGURES/sphere_radiate,Relative Error,max,0.07,Radiation,bs,b,TeX
diff --git a/Verification/HVAC/HVAC_geom.csv b/Verification/HVAC/HVAC_geom.csv
@@ -0,0 +1,3 @@
+Time,V
+4.00E+00,2.00E+00
+5.00E+00,2.00E+00
diff --git a/Verification/HVAC/HVAC_geom.fds b/Verification/HVAC/HVAC_geom.fds
@@ -0,0 +1,37 @@
+&HEAD CHID='HVAC_geom'/
+
+&MESH XB=0,2,0,0.5,0,1,IJK=40,10,20/
+&MESH XB=0,2,0.5,1.0,0,1,IJK=40,10,20/
+
+&TIME T_END=5/
+
+&VENT XB=0.0,0.0,0.4,0.6,0.4,0.6,SURF_ID='HVAC',COLOR='YELLOW',ID='M1 IN'/
+&VENT XB=2.0,2.0,0.4,0.6,0.4,0.6,SURF_ID='HVAC',COLOR='PURPLE',ID='M2 OUT'/
+
+&OBST XB=0.95,1.05,0,1,0,1/
+
+&SURF ID='M1 OUT',COLOR='GREEN',NODE_ID='M1 OUT'/
+&SURF ID='M2 IN',COLOR='BLUE',NODE_ID='M2 IN'/
+&SURF ID='DUCT',COLOR='GRAY 50'/
+
+&GEOM ID='DUCT',XB=0.5,1.5,0.4,0.6,0.4,0.6,SURF_ID6='M1 OUT','M2 IN','DUCT','DUCT','DUCT','DUCT',MOVE_ID='M1'/
+&MOVE ID='M1',X0=1,Y0=0.5,Z0=0.5,AXIS=1,1,1,ROTATION_ANGLE=15/
+
+&HVAC ID='M1 IN AMB',TYPE_ID='NODE',AMBIENT=T,DUCT_ID='M1L',XYZ=-0.2,0.5,0.5/
+&HVAC ID='M1 IN',TYPE_ID='NODE',VENT_ID='M1 IN',DUCT_ID='M1L'/
+&HVAC ID='M1L',TYPE_ID='DUCT',NODE_ID='M1 IN AMB','M1 IN',AREA=0.04,LOSS=1,1/
+
+&HVAC ID='M2 OUT',TYPE_ID='NODE',VENT_ID='M2 OUT',DUCT_ID='M2R'/
+&HVAC ID='M2 OUT AMB',TYPE_ID='NODE',AMBIENT=T,DUCT_ID='M2R',XYZ=2.2,0.5,0.5/
+&HVAC ID='M2R',TYPE_ID='DUCT',NODE_ID='M2 OUT','M2 OUT AMB',AREA=0.04,LOSS=1,1/
+
+&HVAC ID='M1 OUT',TYPE_ID='NODE',DUCT_ID='M1M2',GEOM=T/
+&HVAC ID='M2 IN',TYPE_ID='NODE',DUCT_ID='M1M2',GEOM=T/
+&HVAC ID='M1M2',TYPE_ID='DUCT',NODE_ID='M1 OUT','M2 IN',AREA=0.04,VOLUME_FLOW=0.08/
+
+&SLCF QUANTITY='VELOCITY',PBZ=0.500/
+&SLCF QUANTITY='VELOCITY',PBY=0.495/
+
+&DEVC ID='L',QUANTITY='DUCT VELOCITY',DUCT_ID='M1L'/
+&DEVC ID='LR',QUANTITY='DUCT VELOCITY',DUCT_ID='M1M2'/
+&DEVC ID='R',QUANTITY='DUCT VELOCITY',DUCT_ID='M2R'/
diff --git a/Verification/HVAC/leak_geom.csv b/Verification/HVAC/leak_geom.csv
@@ -0,0 +1,3 @@
+Time,V
+4.00E+00,1.00E-01
+5.00E+00,1.00E-01
diff --git a/Verification/HVAC/leak_geom.fds b/Verification/HVAC/leak_geom.fds
@@ -0,0 +1,41 @@
+&HEAD CHID='leak_geom'/
+
+&MESH XB=0,3,0,1,0,1,IJK=60,20,20/
+
+&MISC STRATIFICATION=F/
+
+&TIME T_END=5/
+
+&OBST XB=0.05,0.10,0,1,0,1/
+&OBST XB=0.95,1.05,0,1,0,1/
+&OBST XB=1.95,2.05,0,1,0,1/
+
+&VENT PBX=0,SURF_ID='OPEN'/
+
+&GEOM ID='L',XB=0.10,0.15,0.4,0.6,0.4,0.6,SURF_ID6='INERT','LEAK L OUT','INERT','INERT','INERT','INERT'/
+&GEOM ID='C',XB=0.90,1.10,0.4,0.6,0.3,0.4,SURF_ID6='LEAK C IN','LEAK C OUT','INERT','INERT','INERT','INERT'/
+&GEOM ID='R',XB=1.90,1.95,0.4,0.6,0.4,0.6,SURF_ID6='LEAK R IN','INERT','INERT','INERT','INERT','INERT'/
+
+&VENT XB=0.05,0.05,0.4,0.6,0.4,0.6,ID='LEAK L IN',COLOR='RED',SURF_ID='INERT'/
+
+&SURF ID='LEAK L OUT',NODE_ID='LEAK L OUT',COLOR='ORANGE'/
+&SURF ID='LEAK C IN',NODE_ID='LEAK C IN',COLOR='YELLOW'/
+&SURF ID='LEAK C OUT',NODE_ID='LEAK C OUT',COLOR='GREEN'/
+&SURF ID='LEAK R IN',NODE_ID='LEAK R IN',COLOR='BLUE'/
+&VENT ID='LEAK R OUT',XB=2.05,2.05,0.4,0.6,0.4,0.6,COLOR='PURPLE',SURF_ID='INERT'/
+&SURF ID='OUTFLOW',VEL=0.1/
+&VENT ID='OUTFLOW',SURF_ID='OUTFLOW',XB=3,3,0.45,0.50,0.45,0.50,COLOR='WHITE'/
+
+&OBST XB=0.90,1.10,0.4,0.6,0.6,0.7/
+&VENT ID='LEAK C IN V',XB=0.90,0.90,0.4,0.6,0.6,0.7,COLOR='CYAN',SURF_ID='INERT'/
+&VENT ID='LEAK C OUT V',XB=1.10,1.10,0.4,0.6,0.6,0.7,COLOR='MAGENTA',SURF_ID='INERT'/
+
+&HVAC ID='L',TYPE_ID='LEAK',VENT_ID='LEAK L IN',VENT2_ID='LEAK L OUT',GEOM2=T,AREA=0.0025/
+&HVAC ID='C',TYPE_ID='LEAK',VENT_ID='LEAK C IN',GEOM=T,VENT2_ID='LEAK C OUT',GEOM2=T,AREA=0.00125/
+&HVAC ID='C V',TYPE_ID='LEAK',VENT_ID='LEAK C IN V',VENT2_ID='LEAK C OUT V',AREA=0.00125/
+&HVAC ID='R',TYPE_ID='LEAK',VENT_ID='LEAK R IN',GEOM=T,VENT2_ID='LEAK R OUT',AREA=0.0025/
+
+&DEVC QUANTITY='DUCT VELOCITY',DUCT_ID='L',ID='L'/
+&DEVC QUANTITY='DUCT VELOCITY',DUCT_ID='C',ID='C'/
+&DEVC QUANTITY='DUCT VELOCITY',DUCT_ID='C V',ID='C V'/
+&DEVC QUANTITY='DUCT VELOCITY',DUCT_ID='R',ID='R'/