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Introduction

This tool is currently under development

How to use the tool

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Examples

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Introduction & summary

In this tool (flowfields) you can compute flowfields in a region of interest, including relevant structures.
The tool requires a shoreline, cross-shore profile and tidal characteristics (you can inspect the generic data availability in the top panel of the tool). Breakwaters will also be used in case they are provided. Breakwaters fully block flow, and can be changed interactively.

The flowfields tool uses the hydrodynamic solver of Delft3D Flexible Mesh. The domain/grid is defined by the user, and generic bathymetry data is automatically interpolated to the model. Boundary conditions are based on generic tide data, and can be defined as water levels or velocities. Finally, any breakwaters are implemented as thin dams in the model, these can be moved interactively.

How to use the tool

1. Open a new project
2. Start in Generic Data by defining a Coastline, a Cross-shore profile (slope) (or spatially varying bathymetry) and tidal characteristics.
3. If required, define breakwater structures.
   <FIGURE>
4. Open the Flowfields tool.
5. Choose a grid resolution and click on the draw grid button <BUTTON>. Now, drag a grid extent on the map, while keeping your left mouse button pressed.
   <FIGURE>
6. Press the (Image Added) button to move and rotate your domain.
   1. Hold CTRL to rotate your grid, the blue box indicates the grid extent, while the arrow indicates the offshore direction.
   2. Hold SHIFT to move your grid, the blue box indicates the grid extent.
7. The type of boundary conditions can be set within this section. You can choose from the following types of boundaries:
   1. Water levels, defined on the offshore boundary
      These are defined by the tidal components from generic data
   2. Currents, defined on the lateral boundaries
      These are defined by the max. horizontal tidal velocities from generic data
8. Press the delete button to delete the coastlines from the map.
9. A spin-up time can be defined (HH:MM:SS format) after which the model will show output on the map
10. By pressing the PLAY button <BUTTON>, the simulation is started.
11. After completing the spin-up period, the model will indicate the water levels and flow velocities.
12. The plotted variables can be changed in the section Visualization
13. During the simulation, any breakwater (point) can be moved around by clicking on <BUTTON>
    1. The interactive flowfields will automatically update
    2. Note that you can also save your breakwater changes to the generic data (for use in other tools), by pressing the button "Set temporary structures to structures"
14. You can interact with the model progress:
    1. Click <BUTTON> to pause
    2. Click <BUTTON> to start/resume
    3. Click <BUTTON> to stop the simulation
    4. Click <BUTTON> to compute a single timestep

Please be aware that the speed of a Delft3D Flexible Mesh model (and thus this tool) scales:

• Linearly with with the number of gridcells
  • E.g. increasing the area of the model domain by a factor 2, will yield a 2 times slower model
• With a power 3 (!) related to the defined cell size
  • E.g. changing the cell size from 200 to 100 m will yield a 8 times slower model (2 x 2= 4 times as much gridcells, while the model timestep also typically decreases by a factor 2)
• Linearly with the maximum flow velocity
  • E.g. increasing the maximum velocity by a factor 2, will yield a 2 times slower model (e.g. by changing a flow boundary condition or by flow contraction using breakwaters)

All other tool modifications, such as visualisation, have a limited effect on model and tool performance.

User input fields

A number of user input fields and funtionality is provided to adjust the model simulation to reflect the local situation. Default values are provided for each input field. The following inputs are defined:

Model domain

• This section allows you to setup the domain of the Delft3D Flexible Mesh model. Apart from buttons that allow you to draw a grid outline and move/rotate it, the following keywords are defined:

Visualization

General

Tool limitations

The Delft3D Flexible Mesh model is a rough representation of the area, and governed by the limitations to boundaries, bathymetry quality etc.

Furthermore, the models are 2-dimensional and do not account for temperature, salinity and sediment transport.

The model files are stored in the following temporary path, for use outside of CoDeS:

• C:\Users\smith\AppData\Roaming\Deltares\CoDeS\Workdir\ (note that in this case, C is the windows-drive, and 'smith' the username 

Example cases

The following files (.dsproject) can be downloaded and loaded into CoDeS to serve as examples. They are not based on actual projects, but are intended as illustration. 

Unzip the files to a convient folder (but make sure the file structure does not change), and open the .dsproject file from within CoDeS.

<EXAMPLE.ZIP>More information will follow