The third idea for tuning to the piano needs the help of your pianist to play each note repeatedly.
On the flute you will be playing a backwards C scale starting two octave above the flute low C, at the top of the middle register. Ask the pianist to repeatedly play this note while you sustain that note on the flute. Your job is to match your flute note to the piano note being repeatedly played. (More to come shortly about using beats for tuning) The reason for the pianist repeating the note is so that you can continually hear the note you are trying to tune to.
Once the pianist and you think the two notes match then you move down to B natural and repeat the process. Continue on down for one octave checking every note of the C scale.
During this exercise you may need to adjust the head joint to be overall more in tune with the piano. (See previous two posts) And of course you can do this exercise on any scale. I like to do this exercise in the key of the piece I am about to play to find the tonal centre of that piece.