Using the uvula also frees the tip of the tongue to actually articulate while fluttering . When using the uvula, even multiphonics can be fluttered . Another type of flutter is the Roar Flutter . It is a noisy, maximum pressure effect best used for rock music. Glissando A smoothly changing pitch, upwards or downwards, produced by sliding the fingers off of or onto the holes on an open hole flute.
Glissandi are easier going up than going down.
They can be done quickly as well. There is a different harmonic series for each fundamental fingering. This is produced by blowing through the flute with the lips totally around the embouchure hole. The angle of the embouchure hole with your mouth will have a lot to do with the pitch of the jet whistle that is produced. They can be very long and soft, or very short and loud.