Difference between revisions of "Viewing 3D TUFLOW FV Results in QGIS"

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==Time Series Plots==
 
==Time Series Plots==
  
The time-series plots allow the modeller to plot the time varying result output.  This can be done for invidiual layers within the 3D water column or it can be depth-averaged over a user-defined set of layers.  The depth-averaged value is that which is akin to a 2D hydro-dynamic solver.
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The time-series plots allow the modeller to plot the time varying result output.  This can be done for invidiual layers within the 3D water column or it can be depth-averaged over a user-defined set of layers.  
  
 
* Select the ‘3D to 2D averaging time series’ tool,[[File:3d to 2d.PNG]].  Using the drop down menu on the side of the tool icon, select the following:-
 
* Select the ‘3D to 2D averaging time series’ tool,[[File:3d to 2d.PNG]].  Using the drop down menu on the side of the tool icon, select the following:-

Revision as of 20:25, 2 August 2020

Introduction

The QGIS TUFLOW Viewer plugin can be used to display TUFLOW FV results, both as 2D results and 3D results. In order to use the TUFLOW FV plotting tools, the TUFLOW Viewer plugin should be version 3.1.1 or later and the version of QGIS used should be 3.14 or later.

  • Open QGIS and open the TUFLOW Viewer plugin.

Opening the Map Output

  • Choose File-> Load Results-Map Output and in the resulting dialog, navigate to the Results/ directory and select the PT_000.nc file.

Load mapoutput.png

This file contains the 3D results. In the previous sections, we assessed the 3D results using a python library. Further development now means those tools are available with the QGIS interface. The following sections outline the various different options for displaying 3D TUFLOW FV results using the QGIS TUFLOW Viewer plugin.

Time Series Plots

The time-series plots allow the modeller to plot the time varying result output. This can be done for invidiual layers within the 3D water column or it can be depth-averaged over a user-defined set of layers.

  • Select the ‘3D to 2D averaging time series’ tool,3d to 2d.PNG. Using the drop down menu on the side of the tool icon, select the following:-

• Single Vertical Layer (from top)
• Multi Vertical Layer (from top)

  • Set the Single vertical layer (from top) parameters as follows:

Single vertical layer.PNG

This will allow the velocity to be plotted for the layer closest to the surface as well as the 5th layer from the surface.

  • Set the Multi vertical layer (from top) parameters as follows:

Multi vertical layer.PNG

This will allow us to plot the depth-averaged velocity for the 5 vertical layers closest to the water surface.

The resulting output shows the velocity within the 3D layers within the water column.

Velocity.PNG

  • Investigate similar outputs for the particle group 1 concentration. The concentration of particles is reported in mg/l.

You’ll see the bulk of the particles occur in the top most layers with little being mixed within the flow depth.

Pt conc.PNG

Note, water depth and water surface elevation do not vary with depth and will therefore cannot be depth-averaged.

Depth-Averaged Cross-Section View

The 3D to 2D averaging cross-section tool allows the modeller to plot the spatial distribution of a results parameter either across a cross section or along a long profile. It allows results output to be plotted for individual 3D layers within the water column or depth-averaging for a number of user-defined layers within the vertical.

  • Use the 3D to 2D Averaging Cross-Section tool,3d to 2d Xsec.PNG, with a similar setup to the above steps to obtain a cross-section of the variation of velocity across a cross-section through the channel width.

Vel xsec.PNG

This shows the velocity in the top layer and the 5th layer from the top showing how velocity varies within the water column.

  • Also, use the tool to take a long section through the reach.

Vel xsec2.PNG

  • Right click on the Cross Section/Long Profile window and choose to ‘Clear Plot Window’. This will clear the existing graphs from the plot window.

Curtain Plot

The curtain plot allows a cross-section to be displayed to assess how a particular results parameter varies in both the horizontal and vertical dimensions.

  • Use the Curtain plot tool, Curtain tool.PNG, to plot a cross-section across the river and assess the horizontal and vertical variation in velocity across the cross-section.

Curtain.PNG

  • Within the QGIS TUFLOW Viewer plugin, open the ‘Settings’ menu and select to ‘Show Grid’ and also ‘Mesh intercept locations (for map plotting line types e.g. cross section).

Settings.PNG

  • Click ok.
  • Create a new curtain plot across the channel. The QGIS window will now show those mesh elements used to generate the curtain plot.

Selected elements.PNG

Vertical Profile Plot

The vertical profile plot, allows the variation of a results parameter through the vertical layers within the water column to be plotting to assess the variation with depth.

  • Select the Vertical Profile Plots tool,Vertical profile tool.PNG, and select ‘Velocity’. Click on the mapped results to plot a the velocity profile through the water column.

Vertical velocity.PNG

Summary

The QGIS TUFLOW Viewer plugin provides an excellent tool to assess the 2D and 3D outputs from TUFLOW FV. It allows a number of different approaches to interrogate and analyse the variation in results parameters in both the horizontal and vertical domains. You can return to the particle tracking tutorial here.