I have a student who finds it hard to get a clear tone on the flute, and I wonder if it has to do with her mouth shape: quite a pronounced dip in the middle of her top lip (leading to a sideways figure of 8 shape/ infinity sign shape to her mouth).
This means that the air tends to get diverted to the sides of the flute embouchure hole, leading to a very breathy and unfocussed sound, and a very wasteful use of air.
She has said that she can't whistle, which I feel may be related to this.....
I have tried various ideas to get her to focus the airstream in the middle, but to little avail.
Because we have spent quite a lot of time on this over the few years I have taught her, she also is also perhaps a little tired of trying out things to do with this.

Has anyone any ideas about this?

Or any ideas of who might have some good suggestions?

What you've described is known as a teardrop embouchure: the teardrop being the little dip in the centre of the top lip. Most of us who have them, including me, tend to form the embouchure slightly to one side. This doesn't cause any long-term problems.

I have a very definite teardrop, but I'm not sure that my embouchure is really off to the side (it's definitely not way to one side, though maybe the airflow isn't even...not sure). As for whistling, I whistle a lot, and consider whistling my "first instrument" .

One point...when I was a teenager, I think I probably treated my embouchure as something decided mostly by the position of the top lip and the muscles at the side of the mouth. Now I find (to the extent that I still play) that my top lip should be firm but not tense, and that manipulating the position of my bottom lip (drawing it in a bit) is more useful. I think I manipulate my bottom lip more than the top lip even in whistling.

Maybe it's because of my mouth shape that I'm firmly in favour of the more relaxed modern embouchure.

It almost sounds to me as if your student is tensing her top lip in such a way as to bring the sides together, which would emphasize the figure 8 shape. I try not to "purse" my top lip inward from the sides, but treat it like a flat flap to manipulate inward and outward.

Middle age relaxes the shape of even cupid lips, so there's hope yet!

My teacher in high school told me that my uneven teeth and full lips made it unlikely that I'd ever be a really top flautist, but I didn't think it was really teeth and lips that were standing in the way of stardom...there was plenty of room for improvement in other areas! Hope your student has not despaired yet.

I have this too.
When i first went to my new flute teacher he noticed my embouchure was on the side and spent some time trying to get me to get it on the centre. I did, and then he realised that was a mistake I had to get it on the side
Now my apperture is to the left (left if you are facing me), and i get a really good generally clear tone. I still find it quite annoying though simply cause i want a 'normal' embouchure but i suppose aslong as i get the right outcome it doesnt matter how i go about it! I think it's a lot more common than people know too

I spent years trying to sort out this problem until I had a lesson with the late Sebastien Bell, whose attitude was that if it worked well why change it. With students who have unfocussed embouchures I find getting them to blow through a thin straw helps - it gives them an idea of how small the hole needs to be amd how the muscles around the mouth should be working.

True
Whilst i was in the very middle of trying to fix this 'problem' i came across a website that said 'if you have a teardrop in your lip dont start the flute, as it will not be possible to play'
I was so disappointed
But now i can play fine, so they were obviously wrong!

I have a copy of 'illustrated flute playing' - the suggestion in there (and I'm quoting, this isn't me!) is either to try and train the embouchure to develop a central hole by using a drinking straw, or to learn to close off one of the holes and blow through the other. I'm sure it can be overcome, as others have already said!

Hi, thanks for all your comments, sorry for the delay in responding: I got your replies via email: all very helpful.
We've just had one lesson (fortnightly), and I've suggested trying to use one side of her mouth: it wasn't a great sound, but I'm hoping that she may give it some time between lessons!

As I'm a bit new to trying this, have any of you "side embouchure" flautists got any tips for developing this, if she's not found her own way of doing this?