Results: Flow and Temperature Distribution with an Iso Surface

In this step, we'll use an iso surface to view the flow and temperature. Iso surfaces are really useful, and show all the areas in the model where the selected result quantity (air velocity, temperature, etc.) is the same value. They can be even be colored by a different quantity to provide great insight into the relationship between two quantities such as air velocity and temperature.

1. Click Iso Surfaces on the Results tab:

2. To create an Iso Surface, click Add on the Iso Surfaces context panel:

Note: This is a good time to rotate the model to see more of the front...

3. Click Edit from the Iso Surfaces context panel.

4. To show the iso surface at a constant velocity value, change the Iso quantity to Velocity Magnitude.

5. The default units of velocity magnitude are in/s. Let's change them to ft/min...

• a. Right click directly on the Velocity Magnitude legend (as shown below).
• b. Click Units.
• c. Select ft/min from the menu.

Note: This helps to view the velocity results using units that are a little more standard in the industry.

6. On the Iso Surface Control dialog box, change the value to 28. (Use the slider or simply key in "28" and click Enter on your keyboard.)

Note: This creates an iso surface that shows the temperature everywhere in the model where the flow is moving at 35 ft/min.

7. Display vectors on the iso surface:

• a. Click the Vector settings tab.
• b. Select Velocity Vector from the Results menu.

• c. You may need to adjust the vector length to see them better. Make them bigger by dragging the Length slider to the right; smaller by dragging to the left:

Note: The model should look like this, but may be slightly different:

Note: This is an interesting composite view into the flow behavior through the hall. The shape of the iso surface is derived from all locations in the flow that have a velocity of 35 ft/min. The vectors show the flow direction at these locations. The color shows the temperature. Notice how the cool air from the supply descends into the seating area. As the air is warmed near the walls, it rises toward the ceiling.

8. To save a Summary Image, click Summary Image from the Results tab.

Note: This image is now saved to the design study. In a few minutes, we'll apply the settings that make up this image to the Winter Scenario, and then compare the two temperature/velocity fields...

9. Because the summary image is saved, we can delete the iso surface. Click the Remove on the Iso Surfaces context panel.

Note: In this step we created an iso surface using velocity as the iso quantity and colored it with temperature results. You can also learn a lot about the thermal performance by using temperature as the iso quantity. This shows areas that are the same temperature, and are really useful for identifying temperature and airflow trends.

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