diff --git a/Manuals/FDS_User_Guide/FDS_User_Guide.tex b/Manuals/FDS_User_Guide/FDS_User_Guide.tex index ebeaa46c0d0..4c32fb79b83 100644 --- a/Manuals/FDS_User_Guide/FDS_User_Guide.tex +++ b/Manuals/FDS_User_Guide/FDS_User_Guide.tex @@ -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} @@ -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 diff --git a/Source/cons.f90 b/Source/cons.f90 index 55082f42e7e..cd3b00b66c7 100644 --- a/Source/cons.f90 +++ b/Source/cons.f90 @@ -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 diff --git a/Source/main.f90 b/Source/main.f90 index 237476bc8e6..bec06cad6b4 100644 --- a/Source/main.f90 +++ b/Source/main.f90 @@ -532,6 +532,11 @@ PROGRAM FDS INITIALIZATION_PHASE = .FALSE. +IF (UNFREEZE_TIME > 0._EB) THEN + FREEZE_VELOCITY=.TRUE. + SOLID_PHASE_ONLY=.TRUE. +ENDIF + IF (MY_RANK==0 .AND. VERBOSE) CALL VERBOSE_PRINTOUT('Starting the time-stepping') !*********************************************************************************************************************************** @@ -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._EB).AND.(T>UNFREEZE_TIME)) THEN + FREEZE_VELOCITY=.FALSE. + SOLID_PHASE_ONLY=.FALSE. + ENDIF + !================================================================================================================================ ! Start of Predictor part of time step !================================================================================================================================ diff --git a/Source/read.f90 b/Source/read.f90 index cec5e3fdd89..5bc905f026a 100644 --- a/Source/read.f90 +++ b/Source/read.f90 @@ -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 @@ -1800,6 +1800,7 @@ SUBROUTINE READ_MISC MAX_LEAK_PATHS = 200 FLUX_LIMITER = 'null' LES_FILTER_TYPE = 'null' +UNFREEZE_TIME = -1._EB ! Initial read of the MISC line