I learned only recently of the existence of a technique that is often called: "Sciarrino Whistle Sound", "Inside Whistle Sound" or "Closed Whistle Tone". It's a technique that is used by Salvatore Sciarrino in "Opera per Flauto", he didn't give it a name, but just described how to execute it. The flutists takes the embouchure hole in between the lips, like for a jetwhistle, but the angle is slightly different. The sound that we hear is a bit similar to the sound of a whistle sound, hence the name.
After examining this technique, I started to suspect that its functioning was much closer to the normal flute sound than to the functioning of whistle sounds. This led to the discovery that in this position we can actually do much more than what is used in compositions of Sciarrino or students of him. We can do glissandi, trills, bisbigliandi, flatterzunge, singing while playing, multiphonics and use it to play melodies with less or more air! You can see some examples in the video.
My research was funded by the FRArt, part of the FNRS, and I was accompanied by the Royal Conservatory of Liège.