Common woodwind instruments, as you know, are blown into from one of the two ends; the acoustic studies for air columns mainly center around these. But I am attempting to understand the acoustics of a woodwind instrument in which one does not blow into one of the ends but rather into a hole in the center, like the Chinese Koudi instrument.
In order to begin attempting to understand the acoustics of such an instrument, I need to know the fundamental frequency of the instrument. So let us say we only have the two open ends, and the hole you blow into (e.g. no tone holes). My first question is: What frequency would resonate based on the length of the instrument (also disregarding end correction for now)?
With that question answered (hopefully), let's say we covered one of the endholes with the blow hole and the other end hole still open, and still lacking tone holes. What frequency would resonate then, and how would it compare to the frequency from the first question?