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Fire Dynamics Simulator Changelog

What's new in Fire Dynamics Simulator 6.7.18

Nov 20, 2021
  • TUNNEL_PRECONDITIONER now works with an arbitrary number of MPI processes, including just one.
  • Add TEMPORAL_STATISTIC='FAVRE RMS'; Favre statistics now work with SPATIAL_STATISTIC='INTERPOLATION'.
  • Add ability to evaporate liquid mixtures.
  • Allow SPATIAL_STATISTIC for a linear array of devices.
  • Add TEMPORAL_STATISTIC to record time to peak value.
  • Add SPATIAL_STATISTIC to compute centroids.
  • Add output for memory (RAM) usage on linux platforms.
  • Add HRR_GAS_ONLY to neglect surface oxidation reactions in total HRR output.
  • Add EMBER_GENERATION_HEIGHT(2) to generate embers at a given height over burning surfaces.

New in Fire Dynamics Simulator 6.7.16 (Jun 2, 2021)

  • A feature has been added that stabilizes simulations of fires or ventilation in long tunnels. The parameter, TUNNEL_PRECONDITION=T on the PRES line causes FDS to solve a 1-D equation for the pressure along the length of the tunnel, greatly speeding up the iterative solution of the Poisson equation for pressure.
  • Mean forcing for wind has been removed, but the basic input parameters for wind remain the same.
  • A gas phase device for 'GAUGE HEAT FLUX' has been added, similar to 'RADIATIVE HEAT FLUX GAS'.
  • The FDS source code now conforms to the 2018 standard.
  • FDS now uses the 2008 Fortran MPI bindings, i.e. USE MPI_F08 instead of USE MPI.
  • Eight point linear interpolation of device output has been added. To access this feature, use SPATIAL_STATISTIC='INTERPOLATION'.
  • Sprinklers and nozzles can be located on or near mesh boundaries.
  • One can create a conically-shaped fixed volumetric heat source.
  • Known droplet issue in FDS 6.7.5 was fixed.
  • Can now specify a PART_ID for a MATL reaction.
  • Can now specify VEL_PART on SURF to assign a velocity to particles being emitted by the surface that is different from any velocity due to gasses being introduced by the surface.
  • New outputs of 'SOLID CELL CONDUCTIVITY' and 'SOLID CELL SPECIFIC HEAT'
  • 'HCN_YIELD' added to REAC and 'FUEL_N__TO_HCN_FRACTION' to COMB.
  • Add subgrid turbulent dispersion model for massive particles (in beta).
  • Add TEMPORAL_STATISTIC='FAVRE AVERAGE'. Currently works with a single QUANTITY and no other statistics (in development).

New in Fire Dynamics Simulator 6.7.15 (Aug 23, 2020)

  • Added four options for using the level set fire spread algorithm for wildfire spread.
  • Fixed bug in burning rate with BURN_AWAY when an OBST abuts a mesh boundary.
  • Fixed bug in user stop of FDS+Evac with MPI
  • Intel has fixed a memory leak related to MPI, which was evident when using the global matrix Poisson solver and MKL library.
  • Added CONE_HEAT_FLUX on SURF which enables a simple model to extrapolate cone calorimeter data to a time-varying incident heat flux.
  • Improvements to volumetric heat sources. This includes allowing for both volumetric heat sources using INIT and gas phase reactions using REAC, specifying the volumetric source RADIATIVE_FRACTION on INIT, and excluding the volumetric heat source from the RTE correction scheme (avoids averaging the source output over any gas phase reaction that is occuring) by RTE_CORRECTION on INIT.
  • On PART, added MASS_TRANSFER_COEFFICIENT, HEAT_TRANSFER_COEFFICIENT_SOLID, and HEAT_TRANSFER_COEFFICIENT_GAS to allow for user specified values.
  • PROJECTION is now .TRUE. by default.
  • Add ABL (atmospheric boundary layer) HEAT_TRANSFER_MODEL (experimental). Uses Monin-Obukhov stability corrections for both momentum flux and heat flux wall functions (see Stoll and Porte-Agel, Boundary-Layer Meteorology, 2008).
  • Fixed a bug in updating the droplet temperature when a droplet is on a wall.
  • Improved the interpolation of wall temperature when a wall cell shrinks or swells.
  • Fixed a bug when MLRPUA is used when there is a MATL with a difference heat of combustion than that on REAC.
  • Add the output WALL ENTHALPY which gives the total enthalpy associated with a wall cell or a solid particle.

New in Fire Dynamics Simulator 6.7.14 (Mar 11, 2020)

  • Allow particles to follow a PATH_RAMP(3) on the INIT line; particle DEVC output works as usual, so this has the effect of allowing DEVC positions to move in time
  • Fix bug with FDS+Evac and ZONEs
  • Fix bug in mass flux of species at exterior boundaries introduced in v6.7.3 for thin obstructions
  • Fix bug that prevented defining an INIT with a species mass fraction of 0 (i.e. override a non-zero MASS_FRACTION_0 on SPEC).
  • Fix bug in the initialization of pressure at ambient ducts nodes to correctly use the reference elevation.
  • Fix bug in the computation of the initial water vapor mass fraction for HUMIDITY.
  • Fix bug preventing the use of TMP_INNER or RAMP_T_I for a particle.
  • Generalize histogram generation for regular devices.
  • Improve MEAN_FORCING functionality by averaging velocity over entire domain, not just entire mesh.
  • Allow level set wildland fire fronts to cross mesh boundaries.
  • Make baroclinic pressure iteration work with GLMAT pressure solver.

New in Fire Dynamics Simulator 6.7.1 (Aug 8, 2018)

  • FDS 6.7.0 (June 20, 2018)
  • SIMULATION_MODE replaces RESEARCH_MODE to control the level of physics. For example, SIMULATION_MODE='DNS', sets the code to run in direct numerical simulation model. Other options include 'LES' (high-fidelity, convergent LES simulations), 'VLES' ("very large-eddy simulation" [default] for coarse-grained, practical LES calculations), and finally 'SVLES' ("Simple VLES", makes simplifying physical assumptions, such as constant specific heat ratio, to speed calculations when appropriate).
  • Create look-up table for CRITICAL_FLAME_TEMPERATURE based on minimum extinguishing concentration (MEC) measurements in cup burner experiments with nitrogen as the diluent.
  • FLUX_LIMITER is now specified using a character string on MISC. Defaults are automatically set by SIMULATION_MODE, as discussed in the user guide.
  • Create a new namelist group called COMB for various global combustion parameters, most of which are numerical and were previously specified on the MISC line. This new namelist group is intended to better organize these parameters, but will typically not be needed by most users.
  • Add PRIORITY to the REAC line for cases with multiple fast serial combustion reactions. Without this parameter, all fast reactions are performed in parallel.
  • Set the default radiation PATH_LENGTH to 0.1 m. Previously it was a function of the cell size.
  • Add I_LOWER_SKIP, etc., to MULT line to more easily embed a fine mesh within an array of coarse meshes.
  • Add SHAPE feature to OBST line. When combined with MULT this allows the user to "sculpt" a basic shape (sphere, cylinder, or cone) out of the obstructions.
  • PYRO3D in Beta testing.
  • Fix temperature error at horizontal mesh refinement boundaries with STRATIFICATION. This problem is relevant for atmospheric flow simulations with mesh refinement (coarsening) in the vertical direction.
  • Ensure that TMP_EXTERIOR at OPEN boundaries is properly applied in radiation transport equation.
  • Make RAMP_SPEED functional in WIND simulations.
  • Add CTRL function types for MIN and MAX.
  • Add XENON as a species to give a low conductivity gas.
  • On MISC remove HVAC_DT and add HVAC_LOCAL_PRESSURE. Setting to FALSE improves stability but requires that VENTs connected to the HVAC system lie in pressure ZONEs as this option no longer uses the perturbation pressure and only uses the background pressure plus any stagnation pressure (i.e. air blown at an inlet will still push air into a duct but a fire in a compartment without a ZONE will not).
  • Fix bug in output values for Fractional Incapacitation Concentration (FIC) with user-defined species.
  • Fix bug when sprinklers are present along with a VENT on a boundary that burns away.
  • Add drift flux model for gas phase thermophoretic movement of aerosols (THERMOPHORETIC_SETTLING on MISC)

New in Fire Dynamics Simulator 6.1.0 (Jun 6, 2014)

  • Parallel Computing:
  • Release OpenMP version as the default.
  • Include additional bundled libraries for MPI Linux versions of FDS.
  • Use MPI_IN_PLACE in MPI_ALLGATHERV calls.
  • Species and Combustion:
  • Fix ability to define a SPEC with a formula and have chemistry picked up by SIMPLE CHEMISTRY.
  • Additional predefined gas and liquid species added
  • Can now define THIRD_BODY reactions (i.e., reactions like A + B + M -> C + M)
  • Boundary Conditions:
  • Fix vent splitting over meshes for HVAC.
  • Add CONVERT_VOLUME_TO_MASS to SURF for VEL type boundary conditions.
  • Change VOLUME_FLUX to VOLUME_FLOW to be consistent with HVAC.
  • Overhauled treatment of mass flux at solid boundaries.
  • Disallow velocity boundary condition for thin obstructions.
  • MAX_LEAK_PATHS may be set by the user
  • Particles:
  • For solid particles with more than one ORIENTATION vector, the radiation heat flux is computed as an integrated average over the appropriate fraction of the surface. Previously, the heat flux was computed to a plate normal to the ORIENTATION vector.
  • Output:
  • Add MASS FLOW WALL, HEAT FLOW WALL, and VOLUME FLOW WALL as SOLID_PHASE_OUTPUT device quantities.
  • Add SPEC_ID to duct output quantities
  • Add QUANTITY_RANGE to DEVC for limiting integration when STATISTICS is set
  • Add AMPUA_Z, CPUA_Z, MPUA_Z, and MPUV_Z output quantities.

New in Fire Dynamics Simulator 6.0.1 (May 15, 2014)

  • The MPI version of FDS is now compiled with Open MPI 1.6.5.
  • Fixes related to lumped species definitions.
  • Use FLUSH statement instead of CLOSE/OPEN in dump routines.
  • Add ability to modify most thermophysical properties for user-defined mixtures.
  • Fix bug in particle tracking algorithm.
  • Fix initialization of back wall temperature.
  • Add inlet velocity profile functionality via RAMP_V_X, etc., on SURF line.
  • Include FDS User, Technical, Verification, Validation, and Configuration guides in bundle.

New in Fire Dynamics Simulator 5.5.3 (Jan 30, 2012)

  • Restoration of the baroclinic torque term in the momentum equation, by default
  • Secondary breakup model for droplets (simplified version of WAVE model by Reitz 1987)
  • Ability to have a RAMP use a DEVC for the independent variable by the keyword DEVC_ID on RAMP
  • Built-in thermophysical properties for a number of liquids (water and some common fuels)
  • Expanded number of gases with built-in thermophysical properties
  • Expanded set of droplet output quantities from PDPA devices
  • RAMPs and TAUs for EXTERNAL_FLUX on SURF
  • RAMP_PART and TAU_PART on SURF to control PARTICLE_MASS_FLUX
  • Use of a SURF line to describe lagrangian particles

New in Fire Dynamics Simulator 5.4 (Jan 30, 2012)

  • Pyrolysis model for solid materials has changed. The most important change is the definition of REFERENCE_TEMPERATURE and the elimination of REFERENCE_RATE. See the FDS User's Guide for more details
  • Werner-Wengle wall model, a better description of the velocity boundary condition
  • OpenMP parallelization option. This will allow you to use multiple cores/processors on a single computer to process a single mesh case, or when combined with MPI, will allow each mesh on each computer to exploit the multiple cores/processors
  • ORIFICE_DIAMETER has been added to PROP inputs to provide a simple way to set droplet velocity. This is an alternative to specifying DROPLET_VELOCITY
  • Thermally-Induced Electrical Failure (THIEF) model added to predict damage to electrical cables

New in Fire Dynamics Simulator 5.3 (Jan 30, 2012)

  • New output quantity: Fractional Effective Dose (FED) by Purser
  • TIME INTEGRAL statistics is availale for device outputs
  • Yields of any explicitly-defined (via the SPEC line) gas species can be specified on the MATL lines using the new parameter NU_GAS
  • The user can specify how the sprinkler pipe pressure depends on the number of open nozzles. The flow rate, droplet speed and median diameter are updated correspondingly
  • The logical keyword DRY has been added to DEVC. When using the mixture fraction and specifying either MASS FRACTION or VOLUME FRACTION, use of DRY will give that fraction minus water vapor (i.e. give an output like a typical gas analyzer)
  • A Phase Doppler Particle Analysis (PDPA) device has been defined for detailed measurements of droplet sprays
  • A new namelist group called MULT (short for multiplier) allows you to multiply OBSTructions and MESHes easily without having to retype the input lines over and over
  • A new parameter called BULK_DENSITY has been added to the OBST namelist group to indicate more easily the total combustible mass within an OBSTruction that can BURN_AWAY
  • Pressure ZONEs can now be opened, and sealed compartments can become unsealed via an OPEN boundary
  • The output quantity that was once called 'soot density' and the newer version, QUANTITY='DENSITY', SPEC_ID='soot', is now in units of kg/m3
  • Device (DEVC) output units can be changed via a CONVERSION_FACTOR

New in Fire Dynamics Simulator 5.2 (Jan 30, 2012)

  • A simple "Eddy Dissipation" model is added to predict the mixing time of fuel and oxygen. Previous versions of FDS used the time step, which was tied to the flow velocity via the CFL criterion. The eddy dissipation model ties the mixing time to the turbulent diffusion coefficient, which is ultimately related to the eddy viscosity of the Smagorinsky form of LES. The eddy dissipation concept is based on scaling arguments and involves an empirical coefficient which has been determined by comparing calculations to classical fire plume experiments and correlations
  • The names of the output quantities have changed, but the old names are still acceptable. The idea is to use parameters like SPEC_ID and PART_ID in conjunction with QUANTITY's like 'MASS FRACTION' and 'VOLUME FRACTION.' Details are in the User's Guide. Also, the underscores in QUANTITY names are no longer needed
  • The default number of droplets introduced in a spray has increased to 5000 per second, and the insertion time has decreased to 0.01 s. The old values were 1000 and 0.05, respectively
  • The mean beam length (PATH_LENGTH) for the radiation solver is no longer based on the size of the overall domain, but rather it defaults to 5 times the mesh cell size
  • It is now possible to declare explicitly a surrogate species for smoke that can be visualized with SMOKE3D and a new output QUANITTY called VISIBILITY