Inlet Pressure for Horizontal Tapered Laterals

Analytical equations are presented for two average pressure correction factors developed for linear displacement laterals with or without outflow at the downstream end. The average correction factor for laterals without downstream outflow, when applied to a relatively large number of outlets is in good agreement with earlier work. For a relatively small number of outlets, the average correction factor presented is more accurate. The average correction factor for laterals with outflow reduces to that for laterals without outflow when the outflow ratio is reduced to zero. For a relatively large number of outlets, this average correction factor is primarily a function of the outflow ratio. For both large outflow ratios and large outlet numbers, the average correction factor is almost a constant. To apply the average correction factor to design a tapered lateral, an expression relating lateral inlet head to required average head and friction head loss has been developed. The expression can be applied to a lateral with any number of reaches with different diameters. A practical application has been demonstrated through an example.