Exercise: Get started with the 3D view in IDA Tunnel-Road Tunnel

Purpose

Learn how to create a simple tunnel system in the 3D view of IDA Tunnel, map sections and routes to the 3D tunnel system, add fans and a fire and animate results.

Background

The 3D view of IDA Tunnel is used to translate the 1D simulation model of the schematic view to a 3D model of the actual tunnel system geometry. The advantages of using the 3D view are to get an easy way of error checking input data, such as section lengths, height coordinates, and cross section areas, the placement of fans, sensors, and fire etc. The 3D view also makes it easier to understand simulation results by animating the result variables as colors on the tunnel tubes and traffic movements as animated 3D trains.

In a real project the 3D model is generally modeled to represent the real geometry of the tunnel system as close as possible. To accomplish that it is beneficial to use drawings and 3D models of the tunnel system and stations as a background when creating the tunnel tubes. In “IDA Tunnel Application, 3D Tutorial” this is gone through in detail. In this exercise we will concentrate on creating a rough 3D model for error checking and results visualization.

Instruction

1. Open an empty system in IDA Tunnel.

Drag in two entries/exits, one tunnel section from the Road library to the schematic view.

Connect these.

2. Click on the left-hand entry component to open the form. Enter vehicle flows of 2000, 140 and 60 vehicles per hour for the three traffic categories.

3. Click on the section component to open the form. Click on the ‘Edit segments’ button. Change the Lanes, left to right to 2 and Lane, right to left to 0.  Also change the right end height to -3.

4. Go to the 3D view. Choose Add… > New tube. Select ROAD-TUNNEL-PROFILE in the Defaults for new tubes dialog. Click Ok.

5. Zoom out the 3D view (scroll down using the mouse scroll wheel) to see all the length of the tube.  Select the left handle and drag it to the left. Check the coordinates in the lower left right and try to have a length more than 1000 meter that is the tunnel section length in the schematic tab.

6. Right click in the 3D view and choose Done.

7. Select the 3D plan tab and drag it away from the other tabs. Place the windows so that you can see both the 3D view and the schematic view. You can use Window > Tile Horizontal.

Select the road section in the schematic view and drag it to the tunnel tube in the 3D view. Release it somewhere in the middle of the tunnel tube. Make sure that the red arrow in the schema and the red/green arrow in the 3D view, point in the same direction. Otherwise, one of them should be flipped. To flip the 3D arrow, click the right mouse button while dragging over the tunnel tube. To flip the schema arrow, click the right mouse button while dragging outside of any tunnel tube.

If the arrow in the 3D view is red, the section does not fit. That means the tube created in previous steps in 3d view is shorter than the section length in the schematic view. This is highlighted more when the left mouse button is released, and the following form pops up that shows the available length in 3D tab is smaller than the tunnel length. If the arrow color is green in 3d plan you can move to the next step.

In that case edit the tunnel tube in 3D view and make it longer. Right-click on the tunnel tube and choose Edit. Move the two end handles. When the tunnel tube is long enough then dragged section to the 3d plan shows a green color.

The tunnel tube of the 3D model serves as placeholders for the section of the schematic view.

You can remap the section by first right-clicking on the section in the schematic view and choosing Remove from 3D view. Then map the section by dragging them from the schematic view again. Remapping should always be done after editing a tunnel tube.

8. On the Schematic tab, choose Select output and select the following under Animation: traffic and NO2 Concentration.

9. Click Run on the schematic tab.

10. Go to the 3D view. Choose Results, select traffic to animate and click Show. The animation of the vehicle’s movement will be shown.

11. Now select NO2 concentration in Results tab of 3D view to animate and click Show. The contours of NO2 concentration will be added to the animation. You can pause the animation or move forward or backward in time with the slider at the bottom right. This is a sample of the simulation results for a normal traffic condition.

12. Let us add a fire. Deselect show traffic and select None in Results from and click on show. Place the mouse pointer on the middle tunnel tube, about 500 m from the tunnel portals. Choose Fire from the right mouse button menu. Give it a length of 10 m and a heat from fire of 10 MW. A fire icon is shown in the 3D view.

13. Change the traffic model to Congestion model in Vehicle form on the schematic view. Rerun the simulation. Now if you check the animated traffic in 3D plan you see the vehicle congested upstream of the fire. On the Schematic tab, select first the left entry/exit and then the right entry/exit and choose Add path report. Select path reports for air temp, wall temp, relative humidity, air speed, extinction coefficient, and mold growth. Click Create.

14. Animate the extinction coefficient. The smoke from the fire can be seen propagating up the tunnel tube driven by the stack effect.

15. The mechanical ventilation system needs to be added to push the smoke to the downstream of the fire. Place the mouse pointer on the left side of the fire, about 250 m from the entry. Right-click and choose New section feature > Jet fan(s). Set the number of jet fans equal to 2 in the form and click okay. A fan icon is shown in the 3D view. Do the same procedure to add a series of jet fans downstream of the fire around 700 m from the tunnel entry. A fan icon is added now at fire downstream in the 3D view.

16. Rerun the simulation. Animate the extinction coefficient. The smoke is initially propagating up the tunnel tube driven by the stack effect. After a while the air flow from the fan is able to change the direction of the smoke propagation and it propagates down the tunnel instead.