UNTRIM2

Basic Information

Name of Program

untrim2

Version-Date

January 2020

Description-Date

January 2022

Catchwords

numerical simulation
finite difference method
finite volume method
sub grid technology
unstructured orthogonal grid
two-dimensional, three-dimensional
unsteady, non-linear
conservative and non-conservative ELM for momentum transport
hydrostatic, non-hydrostatic
reynoldsaveraged Navier Stokes equations (RANS)
tidal dynamics (long waves)
transport of conservative substances (salt, temperature, suspended sediments, tracers)
two-equation turbulence modelling
weirs and imposed surfaces (pressurized flow)
numerical method UNTRIM2
sub-model for water density EQS
sub-model for mixing length turbulence modelling MIX
sub-model for settling velocity modelling SV
sub-model for morphodynamics SEDIMORPH (partially implemented)
sub-model for dredging and disposal DredgeSim (not implemented yet)
sub-model for short waves K-Model
portable SMP-programming using OpenMP
offline coupling with D-Water Quality Delft3D Suite
optional computation of chunk sizes for result variables (see File Chunking)
Storage of the content of the ASCII input control files in netcdf.nc (as a variable)
Storage of MD5 hash values ​​of input files in netcdf.nc (as a variable)

Acknowledgment: This project took advantage of netCDF software developed by UCAR/Unidata (www.unidata.ucar.edu/software/netcdf/).

Short Description of Functionality

Method

The three-dimensional finite difference / finite volume numerical model UNTRIM2 can be used to simulate flow and transport processes in different free-surface flow problems. In contrast to conventional finite difference methods UNTRIM2 is able to operate on an unstructured orthogonal grid. The bathymetry of the model domain can be described with higher resolution compared to the computational grid using sub grid technology.

Physical Processes

The following physical processes are currently taken into account by UnTRIM2:

• reynoldsaveraged Navier-Stokes equations (RANS)
  • local acceleration (inertia)
  • advective acceleration
  • Coriolis acceleration
  • barotropic pressure gradient
  • baroclinic pressure gradient
  • hydrostatic or non-hydrostatic pressure
  • horizontal turbulent viscosity
  • vertical turbulent viscosity influenced by density stratification
  • bottom friction
  • wind friction
  • sources and sinks
  • bottom evolution
  • horizontal acceleration due to wave effects (by means of radiation stress)
  • morphodynamic bathymetry
  • body forces due to short waves
• transport of substances
  • local rate of change of concentration
  • advective rate of change of concentration
  • optional flux limiter : Minmod, van Leer or Superbee
  • horizontal turbulent diffusivity
  • vertical turbulent diffusivity influenced by density stratification
  • settling of particles, deposition and erosion (for suspended sediments)
  • sources and sinks
  • sinks with immediate return inflow at a different location, with optional modification of inflow-temperature as well as -salinity
• turbulence modelling
  • constant
  • mixing length (various parametrizations)
  • two-equation model (turbulent kinetic energy, generic length scale)

Primary Computational Results

• free surface elevation
• bottom bathymetry and bed evolution rate
• current velocity
• concentration of substances (salinity, temperature, suspended load, tracers)
• turbulent kinetic energy and turbulent length scale
• hydrodynamic pressure

Input-Files

1. general input data (filetype untrim2.dat)
2. all other input data are described in the aforementioned input file as well as in the further used steering files listed there.

Output-Files

1. all output data files are either described with filteype untrim2.dat or with all other filteypes used in the aforementioned master input file. See also cf-netcdf.nc and WAQ-files.
2. printer file with informations on program execution (filetype untrim2.master.sdr).
3. (optional) trace file (filetype untrim2.trc).

Methodology

-

Program(s) to run before this Program

CREATE_SIMPLE_UNTRIM2_GRID, DATACONVERT, NCDVAR, NCMERGE, UTRPRE, UTRRND

Program(s) to run after this Program

ABDF, DAVIT, GVIEW2D, LQ2PRO, NCAGGREGATE, NCANALYSE, NCAUTO, NCCHUNKIE, NCCUTOUT, NCDELTA, NCDVAR, NCMERGE, NCPLOT, NCVIEW2D, NC2TABLE, QUICKPLOT, VVIEW2D, ZEITR

Additional Information

Language

Fortran90

Additional software

-

Original Version

V. Casulli, G. Lang

Maintenance

E. Rudolph, A. Sehili, H. Weilbeer

Documentation/Literature

• please refer to $PROGHOME/examples/untrim2009/

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