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FDS Source and FDS_User_Guide Add UNFREEZE_TIME parameter #14413

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Merged
marcosvanella merged 6 commits into from
Mar 24, 2025
Merged

FDS Source and FDS_User_Guide Add UNFREEZE_TIME parameter #14413

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3784c10
add UNFREEZE_TIME input parameter
Mar 19, 2025
8c3d0d8
move UNFREEZE_TIME declaration to cons
Mar 19, 2025
be9c1af
add SOLID_PHASE_ONLY to UNFREEZE_TIME option
Mar 19, 2025
df9aec4
Merge branch 'firemodels:master' into unfreeze
Mar 21, 2025
06f74e6
FDS_USER_GUIDE: add UNFREEZE_TIME to guide
Mar 24, 2025
0693168
FDS Source update FREEZE_TIME logical comp to use _EB
Mar 24, 2025
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6 changes: 6 additions & 0 deletions Manuals/FDS_User_Guide/FDS_User_Guide.tex
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Expand Up @@ -9259,6 +9259,11 @@ \subsection*{Reading the Fields}
\end{lstlisting}
and FDS will read, for example, \ct{CHID_uvw_t1_m1.csv} through \ct{CHID_uvw_t1_m16.csv} in the order of the \ct{MESH} lines (note that a \ct{MULT} line for the meshes may also be used).

\section{Unfreezing the Initial Flow Field}
\label{info:FREZ}

It may be useful to allow the solid phase to respond to an established flow field at the start of a simulation. This could be accomplished with the normal restart functionality; however, this limits the number of changes that can be made to the model before a restart is made. The \ct{UNFREEZE_TIME} parameter on the \ct{MISC} line can be used for this purpose. When set, the initial flow field is frozen with the options \ct{FREEZE_VELOCITY} and \ct{SOLID_PHASE_ONLY} set until the simulation time exceeds \ct{UNFREEZE_TIME}.


\section{Gravity}
\label{info:GVEC}
Expand Down Expand Up @@ -12731,6 +12736,7 @@ \section{\texorpdfstring{{\tt MISC}}{MISC} (Miscellaneous Parameters)}
\ct{TMPA} & Real & Section~\ref{info:MISC_Basics} & $^\circ$C & 20. \\ \hline
\ct{TURBULENCE_MODEL} & Character & Section~\ref{info:LES} & & \ct{'DEARDORFF'} \\ \hline
\ct{TURBULENT_DEPOSITION} & Logical & Section~\ref{info:deposition} & & \ct{T} \\ \hline
\ct{UNFREEZE_TIME} & Real & Section~\ref{info:FREZ} & & \\ \hline
\ct{VERBOSE} & Logical & Section~\ref{info:multimesh} & & \\ \hline
\ct{VISIBILITY_FACTOR} & Real & Section~\ref{info:visibility} & & 3 \\ \hline
\ct{VN_MAX} & Real & Section~\ref{info:VN} & & 1.0 \\ \hline
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1 change: 1 addition & 0 deletions Source/cons.f90
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Expand Up @@ -394,6 +394,7 @@ MODULE GLOBAL_CONSTANTS
REAL(EB) :: DT_END_MINIMUM=TWO_EPSILON_EB !< Smallest possible final time step (s)
REAL(EB) :: DT_END_FILL=1.E-6_EB
INTEGER :: DIAGNOSTICS_INTERVAL !< Number of time steps between diagnostic outputs
REAL(EB) :: UNFREEZE_TIME !< Time to unfreeze a simulation

! Combustion parameters

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10 changes: 10 additions & 0 deletions Source/main.f90
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Expand Up @@ -532,6 +532,11 @@ PROGRAM FDS

INITIALIZATION_PHASE = .FALSE.

IF (UNFREEZE_TIME > 0) THEN
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@marcosvanella marcosvanella Mar 24, 2025

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Should this be UNFREEZE_TIME > 0._EB?

FREEZE_VELOCITY=.TRUE.
SOLID_PHASE_ONLY=.TRUE.
ENDIF

IF (MY_RANK==0 .AND. VERBOSE) CALL VERBOSE_PRINTOUT('Starting the time-stepping')

!***********************************************************************************************************************************
Expand Down Expand Up @@ -569,6 +574,11 @@ PROGRAM FDS
LO10 = INT(LOG10(REAL(MAX(1,ABS(ICYC)),EB)))
IF (MOD(ICYC,10**LO10)==0 .OR. MOD(ICYC,DIAGNOSTICS_INTERVAL)==0 .OR. (T+DT)>=T_END) DIAGNOSTICS = .TRUE.

IF ((UNFREEZE_TIME > 0).AND.(T>UNFREEZE_TIME)) THEN
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@marcosvanella marcosvanella Mar 24, 2025

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same here UNFREEZE_TIME > 0._EB

FREEZE_VELOCITY=.FALSE.
SOLID_PHASE_ONLY=.FALSE.
ENDIF

!================================================================================================================================
! Start of Predictor part of time step
!================================================================================================================================
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3 changes: 2 additions & 1 deletion Source/read.f90
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Expand Up @@ -1746,7 +1746,7 @@ SUBROUTINE READ_MISC
RND_SEED,SIMULATION_MODE,SMOKE_ALBEDO,SOLID_PHASE_ONLY,SOOT_DENSITY,SOOT_OXIDATION,&
TAU_DEFAULT,TENSOR_DIFFUSIVITY,TERRAIN_IMAGE,TEST_NEW_CHAR_MODEL,TEXTURE_ORIGIN,&
THERMOPHORETIC_DEPOSITION,THERMOPHORETIC_SETTLING,THICKEN_OBSTRUCTIONS,&
TMPA,TURBULENCE_MODEL,TURBULENT_DEPOSITION,UVW_FILE,&
TMPA,TURBULENCE_MODEL,TURBULENT_DEPOSITION,UVW_FILE,UNFREEZE_TIME,&
VERBOSE,VISIBILITY_FACTOR,VN_MAX,VN_MIN,Y_CO2_INFTY,Y_O2_INFTY,&
RADIATION,STRATIFICATION,SUPPRESSION

Expand Down Expand Up @@ -1800,6 +1800,7 @@ SUBROUTINE READ_MISC
MAX_LEAK_PATHS = 200
FLUX_LIMITER = 'null'
LES_FILTER_TYPE = 'null'
UNFREEZE_TIME = -1
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also here -1._EB?


! Initial read of the MISC line

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