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Mathematical-computational optimisation models of irrigation networks with a distributed flow that are capable of providing hydraulic data are important for understanding the behaviour of a system in relation to the distribution of the hydraulic head (energy) and the pressure in the pipes of the network. The objective of this study was to examine the distribution of the parameters ofhydraulic irrigation pipes, which were optimised using genetic algorithms. The degree of the op- timisation was evaluated with the help of the genetic algorithms based on the diameters of stretchof the network: two for the lateral lines, four for the derivation lines, four for the secondary lines and one for the main line. A MatLab code was developed that considered all of the losses of energy, both distributed losses and those at specific locations between the beginning of the network and the pump system. The sensitivity analysis was based on the variations in the slope of the ground (0%, 2.5% and 5%). The results show that for pipes with a distributed flow, the influence of the behaviour of the kinetic energy in the pipe contributed to the distance between the energy lines and the piezometric lines at the beginning of each stretch after the decrease in the diameter of the pipes. At the end of the pipes, the values of the energy lines and the piezometric lines were very similar, and they were essentially the same for the final emitter.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T04:22:09Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:28:02Z : No. of bitstreams: 1 2-s2.0-0023797523.pdf: 316387 bytes, checksum: 32acdd14e8a575eef48614f09e5ffeff (MD5) Made available in DSpace on 2014-05-27T04:22:09Z (GMT). No. of bitstreams: 0 Previous issue date: 1988-02-01 An adjusted F factor to compute pressure head loss in pipes having multiple, equally spaced outlets is derived for any given distance from the first outlet to the beginning of the pipe. The proposed factor is dependent on the number of outlets and is expressed as a function of the J. E. Christiansen's F factor. It may be useful to irrigation engineers to estimate friction in sprinkle and trickle irrigation laterals and manifolds, as well as gated pipes. Faculdade de Ciencias Agronomicas-UNESP, Botucatu-SP, Braz, Faculdade de Ciencias Agronomicas-UNESP, Botucatu-SP, Braz Faculdade de Ciencias Agronomicas-UNESP, Botucatu-SP, Braz, Faculdade de Ciencias Agronomicas-UNESP, Botucatu-SP, Braz