Very nice as always. I've never seen clusters used canonically before. Having the imitation enter on an offbeat makes perfect sense, since it doesn't overload the down beats with notes. The ending was perfect.
In measures 9 and 10, you should have your eighth note beamed to the 16th notes, then tied to the dotted half notes. This keeps the piece looking as if it's in 4/4.
Your friend is right, in beaming the 16th notes; having them only in two without beaming them to the beat looks strange.
From your section from m. 34 onwards, the beat becomes confused they way you've written it. Classical theory is one to say your beaming needs to make sense to the beats given in 4/4. If it's a conscious choice, then ignore me. The piece sounds pretty traditional, so I thought that may be decent advice.
Here's the big one. I think you really underutilize the flute in this piece. I tried playing this briefly and it seems very reserved in how it was written; very to the beat, yeah? The flute's capable of gorgeous trills, nice runs, and hearing a flute player exaggerate dynamics is always great to hear. If your friend likes it the way it is though, don't worry about it too much. It certainly gets the point across.
Your piece sounds very nice. The form you wanted to use was pleasantly executed! The beaming thing is just engraving but I just think you could add a lot more to make this so much more vivid. Cheers, and congrats!
A short unaccompanied solo I wrote for one of my flutist friends. My basic train of thought when conducting this was to present a few themes, and then restate them in loose variation style, present a new theme, so on and so forth. When I presented it to her, her only complaint was my grouping sixteenth notes around a key change at measures 15 and 16. I hope some flutists and composers can offer advice and criticisms.
Thank you both for the responses. I'm glad that it sounds at least close to a rag piece.
Monarcheon- It's interesting that you point out the B natural in m. 3. When writing this piece, I actually thought to myself (and still do a bit) that m. 3 sounded a bit off. Glad to know that I'm not the only one. I'll take your comment about dominant 7th chords into consideration for my next piece; I certainly don't want all my pieces to sound like early 20th century rag pieces!