TUFLOW FV Glossary

.2dm	An extension for the mesh geometry file, containing the 2D geometry of the model mesh and elevations - Mandatory for 2D and 3D modelling.
2d_mat_	A suggested file prefix for the 2D land use materials - GIS input data layers.
2d_ns_	A suggested file prefix for the nodestrings of the GIS data type.
2d_zln_	A suggested file prefix for the GIS input data layers of elevation lines (Breaklines).
3D Module	A module in TUFLOW FV that allows users to perform 3D simulation.
Absolute file path	An absolute path starts from the root location (hard drive) and ends with the other subdirectories.
Acoustic Doppler Current Profiler (ADCP)	A device that uses sound waves to measure the speed and direction of currents throughout the water flow.
Active/inactive area	This concept allows users to switch the cells with a given material ID off for the purposes of the hydrodynamic calculations.
Adaptive timestep	TUFLOW FV uses an adaptive timestep where a stable time step must be bounded by the Courant-Friedrich-Lewy (CFL) criterion for the wave propagation and advective terms.
Advection Dispersion (AD) Module	A module that refers to the transport of dissolved constitute within hydrodynamics flow. This module is used to simulate the time evolution of salinity, temperature, suspended sediment, passive tracers, and water quality constitutes.
Advective terms	Terms in the non-linear shallow water equations corresponding to the transport of a flow property by the bulk motion – Divergence of the product of velocity vector multiplied by the flow property.
API	Application Programming Interface – A mechanism that enable two software to transfer data with each other.
Aquaveo SMS	SMS is a software from Aquaveo to create an unstructured mesh, develop TUFLOW FV models and review results.
ArcMap/ArcGIS	ArcMap, also referred to as ArcGIS, is distributed by ESRI (https://www.esri.com). ArcMap is a GIS software package that can be used to develop the georeferenced input data for TUFLOW FV. TUFLOW FV writes result and check files which are compatible with ArcMap also.
.asc	ESRI ASCII grid – An extension file for the GIS grid file. Typically used to assign bathymetry or topography.
Atmospheric stability	A parameter needs to be defined in the case of Kondo wind stress model.
Attribute	Data associated with / or attached to a GIS object. For example, an elevation is attached to a point using a column of data named “Height”. The “Height” of the point is an attribute of the point.
Autoweir	A single nodestring structure type. This structure type instructs TUFLOW FV to identify all cell faces in the model domain that are elevated above the adjacent cell’s centroid elevations. These cell faces are then assigned a weir flow condition.
Baroclinic	A state in which density depends on other properties such as temperature and pressure gradient.
.bat	A filename extension of the batch files (see batch file).
Batch file	A script file consisting of series of commands to be executed by the command-line interpreter, stored in a plain text file. TUFLOW FV offers a number of ways of initiating simulations. Batch files can be set up to loop through events and scenarios to run a multitude of simulations or to push simulations to different processors.
Bathymetry	Elevations below the water surface in open channels, rivers, seas or oceans.
bc_dbase	A folder name to save boundary conditions files.
Boundary conditions	Constraints that are defined to the model to solve system of differential equations.
Boussinesq assumptions	Assumptions used to derive the non-linear shallow water equations.
Breakline layers	A feature for defining the crest elevation of levees or raised roads which traverse a floodplain, or alternatively the bed elevation of tributary creeks.
Bubbler	A destratification unit function type.
Build	The TUFLOW FV Build number is in the format of major.minor.patch. For example, the 2023.0.0 release is the 2023 major version, 0 minor version and 0 patch version. The Build number is written to the top of TUFLOW FV log files so that it is clear what version of the software was used to simulate the model.
CAD	Computer Aided Design.
Calibration	Calibration is the process where the parameters of a model are adjusted, within reasonable bounds, so that simulation results match observed measurements.
Cell	Quadrilateral or triangular shaped computational element in a domain.
Cell centred scheme	TUFLOW FV uses a cell centred scheme with a single bed elevation value assigned to each cell in its calculations, and then produces output that is applicable for each cell (cell velocities are derived from the values across each cell face).
Cell or Zone (Multiple cells)	A type of structure that can change properties of a cell, or group of cells, as a function of time or based on a reaction to model parameters at other locations in the model.
Centroid	The centre of a region, polygon or cell.
CFSR	Climate Forecast System Reanalyses. Model providing estimates of atmospheric, land and oceanic climate variables.
Command	TUFLOW FV text instruction in a control file.
Conserved variables	Conserved variables are the physical quantities that are tracked by TUFLOW FV and are conserved within the numerics of the model.
Control file	Text file containing a series of commands (instructions) that control how a simulation proceeds or a 1D, 2D or domain is built.
Coriolis coefficient	A coefficient associated with Coriolis Force - a source term to the non-linear shallow water equations.
Coriolis deflection	A deflection of any object due to the Coriolis Force is called Coriolis deflection.
Courant-Friedrich-Lewy (CFL)	A convergence condition to numerically solve partial differential equations using explicit time integration, in which the timestep must be less that a certain value to get the accurate results. In other word, the mesh element size must be greater than the distance that any information transfers during one timestep.
.CSV	The file extension of comma delimited text files.
Curtain boundary conditions	A type of boundary condition that allows variation along a nodestring (chainage) and with depth (if required).
Darcy’s law	An equation that represents the flow of fluid through a porous medium.
.dat	An extension for the SMS data file – TUFLOW FV map output can be written in SMS .dat format.
.dbf	Industry standard database file format used by ESRI GIS .shp layers to store attribute data.
DEM	Digital Elevation Model- A regular structured grid of elevation values.
Demo Mode	A Free or Demo Mode allows license free simulation of models under a certain size and runtime.
Diffusive terms	Terms in the non-linear shallow water equations corresponding to the transport of a flow property by the random motion – For example: divergence of shear stress.
Dir	Mean wave direction (degrees) - A requirement to specify wave boundary conditions.
Discrete Lagrangian particle	The TUFLOW FV Particle Tracking (PT) Module enables the 2D or 3D simulation of discrete Lagrangian particles as they are transported by a flow field and/or other forcing terms (e.g., wind drift.
Drying value	The drying value corresponds to a minimum depth below which the cell is dropped from computations.
DTM	Digital Terrain Model.
E3T	A part of .2dm file content. The “E3T” lines are triangular elements. Each E3T line describes the element ID, the three nodes that define its connectivity and spatial extent (in a counter-clockwise direction) and the material type.
E4Q	A part of .2dm file content. Lines that commence with an “E4Q” are quadrilateral (4 sided) elements. Each E4Q line describes the element ID, the four nodes that define its connectivity and spatial extent (in a counter-clockwise direction) and the material type.
Eddy viscosity	A factor describing the turbulent transfer of momentum by eddies generating an internal friction.
Eddy-viscosity terms	Terms including horizonal and vertical components to model the Reynold stresses to describe turbulence flow.
Elder model	An option in TUFLOW FV to calculate the horizontal-mixing scalar diffusivity.
Element	Quadrilateral or triangular shaped computational cell in a domain.
ERA5	European Centre for Medium-Range Weather Forecasts – fifth generation reanalysis. Model providing estimates of atmospheric, land and oceanic climate variables.
Eulerian scheme	A method when fluid motion is investigated at specific locations. This scheme is used in TUFLOW FV’s Modules such as Advection Dispersion, Sediment Transport and Water Quality.
External mode timestep	A 2D depth-averaged reduction of the 3D non-linear shallow water equations is solved multiple times, using a timestep that obeys the barotropic Courant-Friedrich-Lewy (CFL) constraint imposed by the shallow water wave speed <math>\overset{\overline{}}{u} \pm \sqrt{\text{gh}}</math> , where <math>\overset{\overline{}}{u}</math> is the depth-averaged current speed). The external mode loop is repeated until the cumulative timestep is approximately equal to the internal mode timestep.
External nodestrings	Nodestings that are assigned separately to the .2dm by GIS layers. Processed by TUFLOW FV on model initialisation.
Finite-volume schemes	A discretisation method used to solve partial differential equations in the form of algebraic equations.
Flexible mesh	A mesh that consists of a network of irregular triangular and quadrilateral elements.
Flux function	Flux functions are used to allow modified flows through nodestring, linked nodestring and linked zones structure types.
Flux/Mass output	A model output reporting concentrations of each scalar conserved variable multiplied by the volume of water or the flow rate respectively.
.flt	Binary float grid format – An extension file for the GIS grid file. Typically used to assign bathymetry or topography.
.fvc	An extension for the TUFLOW FV simulation control file in a text format.
.fvptm	An extension for the TUFLOW FV particle tracking control file in a text format.
.fvsed	An extension for the TUFLOW FV sediment control file in a text format.
Gauss’ theorem	A theory which relates the flux of a vector field through a closed surface to the divergence of the field in the volume enclosed.
Geographic Coordinate System	A spherical coordinate system that allows for the curved surface of the earth. When run in spherical mode TUFLOW FV requires that all GIS layers imported or exported by TUFLOW FV must be in the same coordinate system.
Ghost cells	Computational cells used internally by TUFLOW FV, that are used to map boundary conditions onto the centroids of boundary cells.
GIS	Geographic Information System, for use in TUFLOW modelling it will need to be able to import/export files in .mif or .shp format.
GNU Octave	A programming language for scientific computing, which can be used to view NetCDF output files.
GOTM	The General Ocean Turbulence Model. One of the external turbulence schemes that can be used in TUFLOW FV to calculate the vertical- mixing eddy-viscosity.
GRIB	GRIdded Binary - A binary format commonly used to store meteorological data.
Heat mass	The temperature concentration multiplied by the water volume.
Hsig	Significant wave height (m) - A requirement to specify wave boundary conditions.
Hybrid z-sigma	A vertical coordinate system used in TUFLOW FV 3D Module in which a series of sigma layers overlayed on a z scheme at depth.
HYCOM	Hybrid Coordinate Ocean Model – An open-source ocean circulation model.
Hydraulic conductivity	A coefficient in Darcy’s equation that represents the property of porous materials.
Incident LW	Incident longwave (infrared) solar radiation.
Incident SW	Incident shortwave (visible) solar radiation.
Include files	To assist in keeping the TUFLOW FV control file (.fvc) succinct and readable it is often desirable (but optional) to use TUFLOW FV’s ‘Include’ file functionality. The Include file allows you to use multiple input .fvc files to minimise repetitive specification of commands common to a group of files.
Initial conditions	Defines the conditions at the beginning of the simulation.
Internal mode timestep	An internal mode timestep is used to initially partially solve a reduced set of equations comprising all terms other than the barotropic (free-surface) pressure-gradients. This internal mode timestep is used to solve internal waves, internal constituents with wave speeds typically an order of magnitude lower than the free surface shallow water wave speed and thus can be run at a much larger timestep than the external mode.
Invert	The elevation of the base (bottom) of a culvert or other structure.
Inviscid flux	Terms derived to solve non-linear shallow water equations. These terms do not have any viscosity terms (derivatives of velocity fields).
ISODATE	A time format option that TUFLOW FV uses, in which data and time inputs are provided in the format dd/mm/yyyy HH:MM:SS.
IWL	Initial Water Level.
Kinematic viscosity	Viscosity divided by its density at the same temperature.
LADS	Laser Airborne Depth Sounder – A bathymetric survey system.
Lagrangian scheme	This term used in comparison with Eulerian scheme. A method to follow the fluid parcel as the fluid flows through space and time. This scheme is used in TUFLOW FV’s Particle Tracking Module.
Land cell	A land cell is one that will never wet, i.e. an inactive cell.
Latent heat transfer	A heat exchange that results in a mass change (evaporation) at a constant temperature.
Latitude	A geographic coordinate to specify the north-south position of a point on the surface of the earth.
Layer	A GIS data layer (referred to as a “table” in MapInfo).
Length scale	A term used in calculating CFL and Peclet criterion.
Libre Office	A free and open-source office software that can be used to build spreadsheets.
LIDAR	Laser Detection and Ranging – A method to obtain the land topography information.
Light extinction	The extinction of four separate wavelength bands (near infrared, photosynthetically available radiation, ultraviolet A and ultraviolet B) through the water column.
Limited Central Difference (LCD)	A value which is set for total variation diminishing reconstruction. An option when using second order spatial solution of the non-linear shallow water equations.
Line	A GIS object defining a straight line defined by two points. See also, polyline (Pline).
Linked nodestrings	A nodestring structure type, where two nodestrings are used to connect two separate locations in the model.
Linked zones	Using this structure type, two locations can be linked as a source/sink term defined by two separate polygons.
Linux	The Linux Operating system, supported by TUFLOW FV.
Local or standalone licence	This type of licence allows up to a specified limit, a number of TUFLOW simulations to be run from the one computer.
Longshore current	A current (or flow) parallel to the shoreline due to oblique waves.
Map output	This output option provides time and spatially varying results that can either be 2D outputs from a 2D depth-averaged model in DATV or XMDF format, a 2D visualisation of a 3D model output in DATV or XMDF format, and Direct 2D or 3D model output in cell-centred NetCDF format.
MapInfo	MapInfo is distributed by Pitney Bowes (https://www.mapinfo.com/). MapInfo is a GIS software package that can be used to develop the georeferenced input data for TUFLOW. TUFLOW writes result and check files which are compatible with MapInfo also.
MAT	See material.
Material	Term used to describe bed type or surface features. Examples of different materials are: river, river bank, mangroves, roads, grazing land, sugar cane, parks, etc.
MATLAB	A programming and numeric computing platform developed by MathWorks. TUFLOW FV offers MATLAB for preparing input data and visualisation.
Maximum Limited Gradient (MLG)	A value which is set for total variation diminishing reconstruction. An option when using second order spatial solution of the non-linear shallow water equations.
.mid	MapInfo Industry standard GIS import/export file that contains the attribute data of geographic objects in a .mif file. The .mif and .mid files are a pair and can’t be opened in GIS unless both files are present.
.mif	MapInfo Industry standard GIS import/export file that contains the attribute data types and the geographic coordinates of objects. The attribute data of the objects is stored in the .mid file by the same filename.
Mode splitting	A scheme, whereby internal and external components of the governing equations are updated using different timesteps selected by considering physical and numerical convergence and stability considerations.
Modules	TUFLOW FV provides optional modules including Advection Dispersion (AD), Sediment Transport and Morphology (ST), Particle Tracking (PT), Water Quality (WQ), 3D modelling and GPU compute capabilities.
Moving boundary conditions	A type of boundary conditions which is useful when simulating a moving source such as the sediment released by a dredger.
MSLP	Mean sea level pressure.
Munk & Anderson limiters	A stability formula used to calculate the vertical mixing model on the “Parametric” option.
Nautical charts	A source of bathymetric data.
.nc	An extension for the NetCDF file – Typically used to store data inputs and TUFLOW FV map output.
NCAR	The US National Centre for Atmospheric Research.
NCEP	The US National Centre for Environmental Prediction.
ND	A part of .2dm file content. Lines that commence with a “ND” are nodes or the points that define the edges of the elements. Each ND line describes the node ID and its x, y and z (i.e., bed level) coordinate.
Near infrared radiation (NIR)	A part of shortwave solar radiation which is specified in Shortwave radiation extinction coefficient command.
NetCDF	A file format that can be used for both input and output files. Inputs are often derived from outputs from other models. TUFLOW FV map output can be written in the NetCDF format.
Network licence	This type of licence allows for multiple TUFLOW processes running at any one time across the organisation’s LAN (Local Area Network) up to a specified limit.
NLSWE	Non-Linear Shallow Water Equations – TUFLOW’s Flexible Mesh Solver calculates 1D, 2D, and 3D non-linear shallow water equations (NLSWE)
Node	The corner of each element in a generated mesh. Water level computation point in a 1D domain. Node in a model mesh used for viewing 2D results in SMS. The nodes are located at the cell corners. Node is also used by MapInfo to refer to vertices along a polyline or a region (polygon).
Nodestring hydraulic structure	A structure type that works by averaging the upstream and downstream primary variables (water depth, current velocity, etc.) and using these to predict the flow exchange based on the selected flux function. For a single location a nodestring is used.
Nodestrings	A series of connected cell faces, selected by a polyline. Used to define boundary condition, flux measurement and structure locations. Can be assigned via the .2dm or as an external nodestring.
Non-penetrative radiation	Long wave radiation.
Notepad++	A free text editor software that can be used for creating TUFLOW FV control files.
NS	A part of .2dm file content. Lines that commence with a “NS” are nodestrings, which are used to define boundary conditions’ locations. Each NS line defines the series of nodes that form the string, the last node number is assigned as negative. The number following the negative number is the nodestring ID and optionally with a nodestring name.
Null cell	A null cell is an inactive 2D cell used for defining the inactive side of an external boundary.
NVIDIA CUDA	A parallel computing platform developed by NVIDIA. TUFLOW FV GPU is available for both Linux and Windows Operating Systems.
OBC boundary condition	Ocean Boundary Conditions - 3D gridded boundary conditions are commonly used to nest a TUFLOW FV model within a coarser scale ocean circulation model, using a combination of 3D open boundaries and initial conditions derived from the parent model.
Obvert	The elevation of the underside (soffit) of a culvert or other structure.
OMP_NUM_THREADS	A user can control the number of threads used during a simulation using the batch file command.
OpenMP	TUFLOW FV is a multi-threaded program based on the OpenMP shared-memory model.
Particle Tracking (PT)	A module that enables the 2D or 3D simulation of discrete Lagrangian particles as they are transported by a flow field and/or other forcing terms. Particle behaviours such as settling, buoyancy, decay, sedimentation and resuspension can all be simulated.
Passive	It indicates that water quality constituents cannot influence each other or be converted from one form to another over time in response to physical inputs such as temperature, light, salinity etc.
Peclet criterion	In addition to CFL criterion, TUFLOW FV uses the Peclet criterion for the diffusive terms to assign the stable time step.
Penetrative radiation	Short wave radiation.
Photsynthetically active radiation (PAR)	A part of heat gain shortwave solar radiation which is specified in Shortwave radiation extinction coefficient command.
Point	GIS object representing a point on the earth’s surface. A point has no length or area.
Point output	This output option provides model parameter time-series or 3D profile time series at point locations, each defined by a x, y coordinate.
Polygon	See region.
Polyline (or Pline)	A GIS object representing one or more lines connected together. A polyline has a length but no area.
Polyline segment	One of the line segments that make up a polyline.
Profile boundary condition	A type of boundary conditions similar to curtain boundary conditions. A profile does not require/use a chainage dimension but instead boundary conditions are applied uniformly along the boundary nodestring. Conditions can be varied with depth.
.prj	An extension for the shapefile format to copy the coordinate reference string.
Projection	A type of coordinate system that projects the curved surface of the earth to a flat surface. When run in cartesian mode TUFLOW FV requires that all GIS layers imported or exported by TUFLOW FV must be in the same map projection.
Profile output	For 3D simulations, profile output at point locations may be requested and output to a NetCDF file.
Python	A programming language which can be used by TUFLOW FV to prepare input data and visualise results.
Python NumPy	Numpy is a Python library used for working on arrays.
QGIS	QGIS is an open source software (www.qgis.org/). QGIS is a GIS software package that can be used to develop the georeferenced input data for TUFLOW. TUFLOW writes result and check files which are compatible with QGIS also.
QPC	Quadtree mesh solver.
R	A programming language for statistical computing.
Read GIS	The TUFLOW command “Read GIS <data type> ==” is used to input spatial data into TUFLOW. For example, Read GIS Nodestring == 2d_ns_myboundaries.mif Would be used to read nodestring location data.
Re-emitted LW	Longwave radiation emitted by the water.
Reflected LW	Reflected longwave solar irradiation as an outgoing heat loss.
Reflected SW	Reflected shortwave (visible) solar irradiation as an outgoing heat loss.
Region	A GIS object representing an enclosed area (ie. a polygon). A region has a centroid, perimeter and area. Polygons can have internal holes.
Regular mesh	An alternative to an external .2dm file to generate the model mesh.
Relative file path	For the relative file path in TUFLOW FV the path is relative to the location of the fvc file. Relative file paths are typically preferred as then the model can be provided to another modeller without changing path names.
Relative humidity	The ratio of the amount of water vapour in the air at a given temperature to the highest possible water vapour amount at that given temperature.
Reserved characters	A non-alphanumeric character including “#”, “!” and ==
Rising Water Software’s GIS Mesher	The GIS Mesher software developed by Rising Water Software can be used to create meshes for hydrodynamic models.
.rst	The file extension for a TUFLOW FV restart file. These files are generated by TUFLOW FV and contain the spatially varying conserved variables at an instant in time.
Salt mass	The salinity concentration multiplied by the water volume.
Saturated vapour pressure	The pressure at which the water vapour is at equilibrium with its liquid state.
Scalar conservation equations	Conservation equations that are solved for the transport of scalar constituents in the water column.
Scalar decay-rate coefficient	A coefficient to calculate the scalar decay as a source component in the scalar conservation equations.
Scalar settling velocity	A velocity which is multiplied by scalar (constituent concentration) to calculate settling as a source component in the scalar conservation equations.
Scalar variables	Scalar variables are physical quantities that are tracked within TUFLOW FV, are conserved and can be represented by one value per cell.
Sediment mass	The sediment concentration multiplied by the water volume.
Sediment Transport and Morphology (ST)	A module to simulate the 2D and 3D sediment transport. The ST Module is a Eulerian solver and tracks sediment mass (bed and suspended load) across discrete control volumes defined by hydrodynamic model mesh or grid.
Sensible heat transfer	A heat exchange that results into a change in water temperature.
Shear stress terms (surface and bottom)	Terms in the sources terms in the case of having shear stress at the surface and bottom of the problem.
Short-wave radiation stress tensor	A tensor in the source terms of non-linear shallow water equations.
.shp	ESRI GIS layer file containing the geographic coordinates of objects. This is referred to as a Shapefile, however, a GIS dataset in Shapefile format will also contain a number of additional file (.dbf, .shx, .prj).
Sigma-coordinate	A vertical coordinate system used in the TUFLOW FV 3D Module in which layers follow the bed profile with the spacing specified as a percentage of the water depth.
Smagorinsky scheme	An option in TUFLOW FV to calculate the horizontal-mixing eddy-viscosity and horizontal-mixing scalar diffusivity.
SMS	Surface Water Modelling Software distributed by Aquaveo (formerly EMS-I) (www.aquaveo.com). SMS can be used to view results and also to create a TUFLOW FV model within the SMS interface. This is commercially available software and a licence is required.
SMS DAT	An output file format.
Snap	When geographic objects are connected exactly at a point or along a side. ArcMap, QGIS and MapInfo all have a “snap” feature, which ensures the features have the same coordinates.
Soffit	The elevation of the underside of a bridge deck or the inner top of a culvert. Same as obvert.
Spatial order	A command that specifies the spatial order of accuracy of the solution schemes. The first-order schemes assume a piecewise constant value of the modelled variables in each cell, whereas the second-order schemes perform a linear reconstruction.
Spatial reconstruction	This allows users to revert an area to first-order calculations where the model is otherwise a second-order model.
Spatial reference system	A framework used to measure locations on the surface of the Earth. TUFLOW FV requires that all input and output files are in the same spatial reference system.
Specific heat	The heat capacity of a sample divided by the mass of the sample.
Specific humidity	The ratio of the mass of water vapor to the total mass.
Stability limit	A maximum water level and maximum velocity which indicate an unstable model. The simulation will stop if these limits are exceeded.
Stefan-Boltzmann Law	It states that the amount of heat radiation from a black body per unit area is proportional to the fourth power of the temperature.
Stokes drift	A wave-induced term resulting in mass transfer.
Structcheck	This structure check file outputs a time-series of the flow and scalar concentrations on the upstream and downstream sides of the structure, as seen by the model when determining any processing internal to the structure.
Structflux	This output can be used to provide the flux that passes through a structure in a similar format to that stored in the standard flux output files.
Structured mesh	A mesh that includes orthogonal quadrilaterals elements for 2D and hexahedral elements for 3D meshes.
.sup	An SMS file extension which is used to combine the input mesh and output results.
Surf zone	The nearshore region where wave shoaling occurs.
Surface roughness length-scale	An alternative model of Bottom Drag Model assumes a log-law velocity profile and requires specification of a surface roughness length-scale.
SWAN	Simulating WAve Nearshore - A spectral wave model developed by Delft University of Technology to compute short-crested wind-generated waves in coastal regions and inland waters.
Textpad	A text editor software that can be used for creating TUFLOW FV control files.
TIN	Triangulated Irregular Network – It can be used to import a simple set of XYZ coordinates.
Tmbot	The bottom wave period (s).
Total Variation Diminishing (TVD)	Values which are set in Horizontal / Vertical Gradient Limiter command to limit schemes employed during the higher-order reconstructions.
TPAR	A file with nonstationary wave parameters to include for boundary conditions.
Tps	Smoothed peak wave period (s) - A requirement to specify wave field.
Tracer mass	The tracer concentration multiplied by the water volume.
TUFLOW FV GPU	TUFLOW FV’s GPU Module is a powerful solver built into our pre-existing TUFLOW FV software. It utilises the substantial parallel computing ability of modern Graphics Processor Units, or GPUs.
TUFLOW FV Wiki	Repository for useful TUFLOW FV information including tutorial models, tips and tricks and help documentation.
Ubot	The rms-value of the maxima of the orbital velocity near the bottom (m/s)
UltraEdit	A commercial text editor software that can be used for creating TUFLOW FV control files.
Ultraviolet radiation	A part of heat gain shortwave solar radiation which is specified in Shortwave radiation extinction coefficient command
UNC file path	Universal Naming Convention – It is used to access the network resources which is prefaced by \\.
Undertow	A current flowing offshore near the seabed in the surf zone when waves are moving the shore.
Unstructured mesh	A mesh that includes non-orthogonal elements such as triangular and quadrilateral elements.
UTM projection	Universal Transverse Mercator – A map projection system for assigning coordinates to locations on the surface of the earth.
Validation	Validation is the process where a calibrated model is compared to observed measurements from a different period with different physical conditions.
Vapour pressure	The pressure derived by vapour above the liquid surface.
Vertex	Digitised point on a line, polyline or region (polygon).
Vertical Mapper	An add-on to MapInfo to perform grid-based analytical functions.
Vertices	Plural of vertex.
Viscous flux	Terms derived to solve non-linear shallow water equations. These terms include viscosity terms (derivatives of velocity fields).
Water Quality (WQ) Module	A TUFLOW FV module that enables the 2D or 3D simulation of water quality and ecological processes in natural and constructed water ways such as lakes, tidal estuaries, river systems and coastal oceans.
Water quality scalar mass	The water quality parameter concentration multiplied by the water volume.
Wave gamma	Maximum ratio of wave height to depth.
Wet value	The wet value corresponds to a minimum depth below which cell momentum is set to zero, in order to avoid unphysical velocities at very low depths.
WIBU Codemeter dongle	TUFLOW FV is licensed using either a WIBU Codemeter (metal) dongle or software licence.
.xmdf	eXtensible Model Data Format – An extension of a file format for the geometric data storage.
XMDF	An output file format.
ZB	A mapped output variable to represent the model bathymetry.
z-coordinate	A vertical coordinate system used in TUFLOW FV 3D Module in which z coordinate layers are set at a series of fixed elevations.