Showing posts with label Schlieren. Show all posts
Showing posts with label Schlieren. Show all posts

Sunday, 12 December 2010

Schlieren Experiment Diagram: 12.12.10



This diagram shows the layout we used for our latest results. We feel that by having the mirror laying on a table top we were able to get clearer images than when we used a clamp vertically. We think this is because the mirror is acrylic and flexes thus giving us inconsistent results. A glass parabolic mirror should have been purchased originally to insure we could gain the best results from the start.

Yellow Schlieren effect video: 12.12.10



This video captured is the most significant result we have had so far in our investigation into the Schlieren effect. The video shows the light projection from the parabolic mirror onto the ceiling above with a shadow of a hand holding the heat source. In the reflection you can see the Schlieren effect, which displays heat particles rising from the lighter and above. The image revels a lot more than what the naked eye can see by looking directly at the lighter. Looking at the projection on the ceiling revels the invisible with the use of a parabolic mirror giving a bubbling effect of what looks like heat emitting from the lighter.

Schliern effect videos: 11.12.10

http://www.facebook.com/video/video.php?v=474696671695&oid=152742014764486

Shimmering yellow Schlieren

http://www.facebook.com/video/video.php?v=474682806695&oid=152742014764486

Schlieren Blue filter

Friday, 10 December 2010

More Schlieren: 10.12.10

Schlieren photography is a visual process that is used to photograph the flow of fluids of varying density

There are several methods commonly used to visualize refractive index or density changes in liquids, gases, liquids and solids.

Generically these include shadowgraphs, schlieren and interferometric techniques. These sytems are used to visualize temperature gradients, shock waves in wind tunnels, nonhomogeneous areas in sheet glass, convection patterns in liquids, etc.

The focusing schlieren method:


http://people.rit.edu/andpph/text-schlieren-focus.html

Wednesday, 10 November 2010

Experiment Two: 10.11.10

Part two:

Experiment Two, part two was using the same materials as in experiments one and two, part one, but laid out in a different arrangement see illustrated diagram below.



Results: We played around with the LED light that we had and created a cover over the top of the light emitting end. The cover was made using a piece of chewing gum packet foil with a hole in the centre which we taped to the light using masking tape. This gave us a beam of light that was very straight/concentrated to start with but as the light distance lengthens the light beam would flare to give a larger diameter of light. We set the lens which was of 10cm focal length lens into the table clap and with a ruler measured 2 x the focal length which is 20cm and placed a stripe of masking tape to the table to represent the correct distance from which the light source should be shone. Instead of using a filter we used a razor blade edge which we taped to a lens holder and placed at the correct distance from the lens at 20 cms along with the light source which we placed in a bendy clap permanently pressing the on button on to give us a constant supply of light. The results we viewed by experimenting not through a camera or a video camera but with our own eyes, as the light reflected off the mirror the reflection ended up being reflected onto a white surface behind us in the studio. We played around with the light source positioning and the white board which we brought closer and we ended up with an image of not only the shadow of the razor blade but an out line of the heat source we used, a lighter. At last we had some sort of image it took a few more further attempts to realise we where visualising the invisible! Although it was small and had no colour due to not using a filter we had our first proper results, very exited... I still need to do further research into why the results with a razor blade were successful and not with the filter, but happy all the same.



See images below:






Part one:

Experiment two, part one was almost a near replica of experiment one but with the whole group present. We set up the equipement that i gathered as illustarted below in a photography studio in the TC buliding, but instead of using my multi bulbed torches we used and experimented with the LED torches and lasers that saally had brought in. Another change to my original set up was that we did not use a digital SLR, but instead used a sony camcorder to record the results and the set up and group interaction.



Results: I feel at this point in our experimentation with the Schliren photography technique that we still didn't quite have the right equipemnet or scientific knowlege to perfect this experiment today. We continued on changing variables within this experiment including the distance between the lense and the filter/light source, LED lights and a red laser, multi coloured spectrum filter and an orange light gel, but still had zero results, a little frustrating. More research needed.