Glossary¶

The list below is a nonexhaustive list of terminology and concepts used in HYDROLIB(-core) and Delft3D Flexible Mesh.

Input file containing the actual forcing data for model forcings specified elsewhere in the model input, for example time series or astronomical components. Originates from boundary conditions as specified in the external forcings file, but nowadays also used in structure files. More details about the syntax and the various supported function types in the Delft3D FM User Manual.

Boundary condition¶

Flow (or constituent) boundary condition that forces a D-Flow FM model, such as waterlevel and discharge boundary conditions. Defined in the external forcings file. More details in the Delft3D FM User Manual.

Branch¶

The network edges in a network topology of 1D models. The computational grid points are positioned on these branches using branch id and a chainage value.

Branch Id¶

Identification text string for a particular branch in a 1D network.

C¶

Chainage¶

The distance along a 1D network branch to define a specific location on that branch. Always used in combination with a branch Id.

CF conventions¶

Established metadata conventions for storing all kinds of data, e.g., model input and output, in NetCDF files. More details on: https://cfconventions.org/. HYDROLIB-core and Delft3D Flexible Mesh rely on CF, and extend this with UGRID conventions where unstructured grids are applicable.

Computational backend¶

Computational core, also called kernel. The program/library of simulation software that does the actual calculations. Often also available with a graphical user interface on top of it.

Cross section files¶

Input files for D-Flow FM that define the 1D network's cross sections. Two parts: cross section definition file and cross section location files. Not to be confused with observation cross section files!

Cross section definition file¶

Input file for D-Flow FM that defines the various cross section shapes in a model with a 1D network. Format is INI-like. More details in the Delft3D FM User Manual.

Cross section location file¶

Input file for D-Flow FM that defines the location of cross section shapes in a model with a 1D network. Each location refers to a (possible shared) cross section definition. Format is INI-like. More details in the Delft3D FM User Manual.

D¶

Deltares conventions¶

A proposal for additional NetCDF conventions that build on the existing UGRID conventions, intended to properly describe 1D network topologies as a coordinate space on which 1D computational grids are defined. Also 1D2D grid couplings are included. More details in: the Delft3D FM User Manual.

D-Flow FM¶

D-Flow Flexible Mesh. The computational backend that solves 1D/2D/3D hydrodynamics in the Delf3D Flexible Mesh Suite. Toplevel input is the MDU file. More details in the Delft3D FM User Manual.

D-HYDRO Suite 1D2D (Beta)¶

Integral software suite for hydraulic 1D2D modelling, including rainfall runoff and realtime control. More details on: https://www.deltares.nl/nl/d-hydro-suite-1d2d-beta/.

DIMR¶

Deltares Integrated Model Runner. Executable/library that runs integrated models by coupling multiple computational backends in a simulation timeloop. Uses a single DIMR config file as input.

DIMR config file¶

Input file for DIMR (typically dimr_config.xml) for an integrated model run, describing which models are coupled and which quantities need to be exchanged.

E¶

Edge (mesh)¶

A geometrical "line" in a 1D, 2D or 3D mesh. Connects two mesh nodes as its end points. Building block of the UGRID-conventions.

External forcings file¶

Input file for D-Flow FM describing model forcings such as boundary conditions, laterals and meteo. Format is INI-like. More details in the Delft3D FM User Manual.

F¶

Face (mesh)¶

A geometrical "cell" in a 2D mesh. Formed by 3 or more mesh nodes as its vertices. Building block of the UGRID-conventions.

Flow link¶

An open connection/interface between two flow nodes in the staggered D-Flow FM model grid. Is the same as a "velocity point", and corresponds with (but is not equal to) an edge, both in 1D and in 2D. In 3D a flow link corresponds with a 3D face between two volumes.

Flow node¶

A single finite volume "cell" in the staggered D-Flow FM model grid. Is the same as a "pressure point", and is in fact a face in 2D/3D or a node in 1D.

G¶

Grid¶

The computational grid on which a flow simulation is done. The grid for D-Flow FM is defined in an input net file, and also appears (slightly differently) in the output map file.

Grid snapping¶

The snapping of D-Flow FM model input in x,y-coordinates to discrete locations in the staggered model grid. This process makes most model input independent of the chosen model grid and grid resolution. Snapping is done either to (sets of) flow nodes or (sequence of) flow links, depending on whether pressure-point data or velocity-point data is concerned.

H¶

His file¶

Output file of D-Flow FM containing model results as time series on a specific set of discrete locations, which are typically the hydraulic structures, observation stations and more. More details in the Delft3D FM User Manual.

I¶

Integrated model¶

Model consisting of more than one model. Typically used when multiple computational backends are coupled, for example D-Flow FM and Rainfall Runoff or D-Flow FM and Real Time Control. Integrated models can be run using the Deltares Integrated Model Runner (DIMR).

INI-files¶

Delft3D FM uses several input files that are formatted in an INI-like syntax. The abstract syntax depends on the particular file type, see: cross section files, initial field file, external forcings file, MDU file, observation files, rougness file, structure file.

Initial field file¶

Input file for D-Flow FM describing initial conditions and other spatially varying parameter fields. Format is INI-like. More details in the Delft3D FM User Manual.

J¶

K¶

L¶

Lateral¶

Lateral discharge in D-Flow FM, which acts as a source (or sink) of volume. Defined in the external forcings file. The actual forcing data may come from timeseries in a .bc file or from RR a coupled/integrated model. More details in the Delft3D FM User Manual.

M¶

Map file¶

Output file of D-Flow FM containing the model results on all grid points. More details in the Delft3D FM User Manual.

MDU file¶

Main input file of D-Flow FM. Format is INI-like. More details in the Delft3D FM User Manual.

meteo¶

Meteorological forcings of a model. Typically sources (or sinks) of volume via precipitation and evaporation, or forcing via wind. For D-Flow FM defined in the external forcings file. More details in the Delft3D FM User Manual.

mesh¶

See grid.

N¶

Net file¶

Or grid file. Input file for D-Flow FM containing the computational model grid. Format is NetCDF, adhering to CF- and UGRID-conventions, and optionally also the Deltares-extension for 1D network topology and geometry.

NetCDF¶

File format used by HYDROLIB-core and Delft3D Flexible Mesh for the model input grid and for model results in output files. These files typically adhere to the CF conventions and sometimes UGRID conventions.

Node (mesh)¶

A geometrical "point" in a 1D, 2D or 3D mesh. Defined by x- and y-coordinate, in 3D also a z-coordinate. Can be connected by mesh edges, and can form the vertices of a mesh face. Building block of the UGRID-conventions.

O¶

Observation files¶

Files that define the model locations for which output should be produced in the his file. Two types: observation point file and observation cross section file.

Observation cross section file¶

Input file for D-Flow FM that describes the model locations for which (cumulative) flow "flux" output should be produced in the his file. For example: cumulative discharge, salinity transport. Applies both to 1D, 2D, 1D2D and 3D models. Format is INI-like. More details in the Delft3D FM User Manual.

Observation point file¶

Input file for D-Flow FM that describes the model point locations for which local output should be produced in the his file. For example: waterlevel, velocity vector/magnitude, tracer concentration as instantanous values. Applies both to 1D, 2D, 1D2D and 3D models. Format is INI-like. More details in the Delft3D FM User Manual.

P¶

Polyline file¶

File containing a sequence of polylines in model coordinates. Each polyline has header lines with a label and row+column count, and at least a list of x, y-points. More than 2 columns may be present (z, data1, ...) for particular model inputs, see for example the fixed weir file. More details in the Delft3D FM User Manual.

Polygon file¶

See polyline file. The point sequences are interpreted as closed polygons.

Q¶

R¶

Rainfall Runoff¶

RR for short. The computational backend that solves lumped rainfall runoff, offering various runoff concepts. Toplevel input is the sobek_3b.fnm file. Part of the D-Hydrology software module. More details on: https://www.deltares.nl/en/software/module/d-hydrology.

Real Time Control¶

RTC for short. The computational backend for real-time control of hydraulic model components (typically hydraulic structures). Toplevel input is in various rtc*.xml files. Part of the D-Real Time Control software module. More details on: https://www.deltares.nl/en/software/module/d-real-time-control.

Roughness file¶

Input file for D-Flow FM describing roughness values on the 1D network. Format is INI-like. More details in the Delft3D FM User Manual.

S¶

Sample file¶

File containing an unstructured set of sample point values. Typically used as input file for initial fields or other spatially varying fields in the initial fields file. More details in the Delft3D FM User Manual.

Staggered grid¶

Discretization method used in D-Flow FM where the PDE variables are not all defined on the same topological grid locations. Water level, concentrations and other volume-related variables are defined on the pressure points (also: flow nodes), and the fluxes and other transport-related variables are defined on the velocity points (also: flow links).

Structure file¶

Input file for D-Flow FM containing the hydraulic structures. Format is INI-like. More details in the Delft3D FM User Manual.

T¶

U¶

UGRID conventions¶

Metadata conventions for storing unstructured grids in NetCDF files. More details on: http://ugrid-conventions.github.io/ugrid-conventions/.

V¶

volume (mesh)¶

A geometrical "cell" in a 3D mesh. Formed by 4 or more mesh nodes as its vertices (or: 4 or more mesh faces as its "sides"). Building block of the UGRID-conventions.