Hydraulic design charts for elliptical pipes.

This paper concerns charts for the hydraulic design of elliptical pipes under partfull
gravity flow conditions. Examples of such pipes are currently commercially available, and may be
laid with the major axis of the cross section either horizontal or vertical. Similar charts have been
published for circular pipes and for pipes of ovoid cross section, which have particular uses in
combined sewerage. Such charts are useful for preliminary sizing and outline design purposes. The
applications of this type of chart to elliptical pipes lead to two distinctive points that will be discussed
in the paper. Firstly, the two possible orientations of the pipe resulted in different sets of lines on the
chart, and these may be used to illustrate the relative performance of the two orientations, which have
different practical benefits. The second point, of somewhat more academic interest, relates to the
geometry of the ellipse. Although the cross sectional area of the ellipse has a well known and exact
mathematical formula, the perimeter of the ellipse does not. Different approximate expressions for
the total perimeter are compared with the elemental approach that was used to establish the pipe cross
section geometry for the computerised production of the design charts.

Citation:
Marriott, M.J. and Uddin, M.S. (2009) ‘Hydraulic design charts for elliptical pipes.’ Proceedings of Advances in Computing and Technology, (AC&T) The School of Computing and Technology 4th Annual Conference, University of East London, pp.120-125.