Interesting sound, I like its tonal dissonant sound!
Check your ranges, you score way to low for cello in some places. They cannot play below a C below the staff. You might consider adding a double bass to carry those low pitches and double the cello at the octave when it's not. Adding the double bass will also add a "bottom" to the piece that might help you achieve the texture I think you're after.
Also, When composing in finale, make sure voice two (red notes) are on the bottom. That way you avoid stem crossings. Also, in measures 29-32 you might want to put a crescendo in the strings, because the flute is playing in a very high register, it will be piercingly loud, and will most likely obliterate sounds coming from the strings, and you can't very well tell a flutist to play something that high quietly.
I'm not sure what this is scored for, but there is not much development, and it ends very abruptly. I'm not sure if this was your intention, but it's just an observation.