This is a tutorial of level 'beginner'. If you have not done so already, familiarise yourself with the DeltaShell User interface here before starting this tutorial.
This tutorial was set-up together with the University of Twente. A basic understanding of hydrodynamics is assumed.
The purpose of this tutorial is to get familiar with the D-Flow-1D module for channel hydraulics. In this tutorial we will set up a simple single-channel model and do basic output viewing.
Step-by-step guide
The system we are going to model is a relatively simple 350 km single-channel river model with a compound channel cross-section.
A working flow model needs at least the following things:
- a network (consisting of branches and nodes)
- at least 1 cross-section per branch
- a computational grid
- boundary conditions
- initial conditions
To make viewing output easier, it also recommended to add observation points.
Add a model and network
- Open SOBEK and add a new 'Flow 1D Model' from the 'New Model' button.
- Take a moment to explore the project explorer and see what components make up a Flow1D model. (If you don't know what the project explorer is, please review these terms here)
To build a network you will need to open the central map by double clicking on network in the project explorer. If you have opened the central map, the ribbon will show the contextual Map tab (in green). In the Map tab, you can build a network with the tools in the Network group. Explore the icons in this group by hovering above them and reading the popup menu.
- Create a network with the 'Add new branch' tool. Draw one branch. Two nodes are automatically created as well.
- You should now see the something like below in your network. If your network looks differently (too many branches, or curved branches), simply select the branches and press 'Delete' in your keyboard to remove the branches and try again.
- Next, we're going to change the coordinates of the nodes. Select a node. In the properties window, change the x, y coordinates and name of the nodes manually to (Name: Begin, x:0 m, y:0 m) and (Name: RiverEnd, x: 350000 m, y:0 m).
Add a second branch attached to the first one. Do this by using the 'Add new branch' tool and starting the branch at the end of the last node. Change the coordinate of the third node to (Name: LakeEnd, x:380000 m, y:0 m).
If the branches are attached, the node will turn solid green. If this is not the case, you will see two nodes - possible close to each other - with white centers. The white centers denote that it is an end-node, i.e. it is only connected to one branch.
This might happen if you clicked to far from the node you want to connect to, or if snapping is not enabled. To enable snapping, press S on your keyboard. Alternatively, you can merge nodes by selecting the new node and editing its coordinates. Nodes will merge automatically if their coordinates are exactly the same.To get an overview of the branches in the model, use the Map explorer to navigate to the flow model/input/network, right-click on branches and select 'Open Attribute table'. You can do this for every component in the model. For example, try to open the attribute table of the nodes in the same way. You should now have a network with two branches and three nodes.
Add cross-sections
To add a cross-section, use the 'Add CrossSection (ZW)' tool and click anywhere on a branch. You can change the name and location (chainage) of a cross-section via the Properties window or its attribute table. In this way, a one cross-section at the beginning of the branch and one at the end of the branch.
To define the cross-section definition, double click on the cross-section. Change the cross-section to resemble the compound channel. Use the following dimensions:
Parameter Value B1 50 B2 70 h1 3.5 To use the same cross-section multiple times, you will need to share the cross-section definition. Still in the cross-section view, click 'Share this definition'. If you define a new cross-section somewhere in the model, you can now use the shared cross-section.
The ZW profile is per definition symmetrical. Note that other types of cross-section exists as well, viz. 'YZ' and 'XYZ', that can be assymetrical as well. However, only ZW profiles can be used in combination with morphology.- To impose a slope, change the Level Shift. By imposing a Level Shift, the cross-section definition is uniformly lowered or heightened.
To see if your model is set-up like you want it, let's take a longitudinal look. To do this, create a route using the 'Add route' tool in Ribbon/map/network.
