Investigating the Kármán vortex street using Energy2D

Run this simulation.

The Kármán vortex street is a repeating pattern of swirling vortices caused by the unsteady separation of flow of a fluid over bluff bodies. It is named after the great scientist Theodore von Kármán who co-founded NASA's JPL. This effect is observable in nature like in a stream, but you need some luck since it requires some picky conditions that are not always there for you.

Now, with our online simulation program Energy2D you can create and investigate the Kármán vortex street in your browser without depending on Mother Nature to give you an opportunity window.

For example, you can test how big an obstacle should be in order to produce this effect. You will find that an obstacle must be large enough to create a steady vortex street. If the shape of the obstacle is not streamlined, what will you see?

If you stick a thermometer in a thermal vortex street, you should see that the temperature will swing pretty regularly between a high value and a low value (see the image to the right). This means this effect could be used to warm and cool an array of things periodically. Could there be some engineering use of this?

YouTube Physics features our infrared videos

AAPT's Physics Teacher runs a column called YouTube Physics edited by Diane Riendeau, an award-winning physics teacher. In May, the entire column featured five intriguing YouTube videos from our IR website and recommended instructional strategies to use them effectively in the classroom.

Diane recently wrote about the YouTube Physics Column: "Through the use of YouTube, we can show our students demos that we do not have the capability of doing in class. We can use these videos to inspire them and show them some of the cutting-edge discoveries in our field. We can also show them videos from around the world. Students need to realize that the physics community is global, not just national. They should learn to marvel in the discoveries made by physicists from all nations."

We resonate with her vision, which is why we are publishing our IR videos on YouTube to allow students from all over the world to learn thermodynamics, heat transfer, chemistry, and other science subjects in everyday phenomena through IR vision. In the long run, we hope this effort will give birth to an "IRTube" that collects IR views of many scientific phenomena. With the introduction of thermal imaging technology into the classroom, we hope students will begin to upload their own IR videos to the IRTube. Darren Binnema, a student from the King's University College in Edmonton, Canada, has contributed the first IR video to the "IRTube." His IR video visualizes the heat of solutions of NaOH and KCl (see the above image).

For more IR videos, please visit the IRTube website.