Well, yes, this is my first post here, and I do hope I got it into the right section (And no, this is not homework, and although I was thinking of posting it there; I also considered posting it in the engineering forum, but I believe it would fit better in general physics forum). Would it be possible to calculate fluid friction against the walls of the tube, if it is moving within a narrowing pipe/tube, which is laid in a fashion that resembles Archimedean Spiral? I've been looking for the solution for past few days, yet most of the fluid friction topics describe drag friction, or contain very vague formulas for "water friction against pipes", but none of the really let me take into the account the decreasing diameter and increasing angle of piping. Additionally, how would that friction change according to the cross-section of the tube/piping (square/oval etc.) Any directions on where to look for the solution of this problem would be appreciated!