Vízügyi Közlemények, 1973 (55. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

(73> 1. at the smallest possible collecting flume dimensions free overfall should prevail event at the greatest discharge, 2. the dissipation of energy should be sufficient to ensure tranquil flow hydraulically in the collecting flume. The problem has been treated exclusively by Frank, Favre, Marchi, Citrini,. Ruggiero, Georgescu, Sassoli and Gusberti. Their results were analysed by Kebelmann and supplemented by experiments he developed methods for computing the surface profiles in rectangular, trapezoidal and parabola cross-sections. The graphical procedure was further simplified by Kebelmann, by constructing nomographs (Fig. 1 ). The characteristics of the surface profile are given by Eqs. (2) to (9) and Fig. 2. The formulae apply to prismatic canals. The influence of spreading has been discussed by Komora. In his investigations he assumed the depth at the terminal cross-section of the collecting flume to equal the critical depth. This is true in certain particular cases only, but does not apply in general. This has been verified also by the experments conducted in Hungary at the Research Institute for Water Resources Development. A situation approximating the theoretical situation resulted only when the collecting flume was deepened. The dissipation conditions of water impinging into the collecting flume are similar to those in stilling pools (Eq.(lO)and Fig. 3). Experiments have been conducted also at the hydraulic laboratory of the Budapest Technical University with the objective of reducing the dimension of the collecting flume. The influence of an inclined weir on glow conditions was investigated (Fig. 4). The properties of water flowing in the collecting flume at rtctangular and trapezoidal cross-sections of different dimensions ( Fig. 5) were also considered. The objective was to make the first steps towards the design of an economical collecting flumes for the discharges commonly encountered in Hungary, namely from 30 to 150cu. m/sec. The experimental results indicated positively that — the conventional lateral weir design is superior in all respects, — widening of the collecting flume is unlikely to result in improvement concerning the critical depth, — the depth of the collecting flume may be 15 to 20% smaller than the value recommended by Kebelmann, and — lor ease of construction and econiics trapezoidal collecting flumes are preferable. Ligetvári, F.: :5. The TrikLon trickling irrigation system (For the Hungarian text seepp. 351) The principles and advantages of the trickling irrigation systems, in particular the TrikLon system are described. The filtered water is delivered by the pump through the principal and secondary pipeline into the laterals (Fig. 3) through which it is conveyed into the trickling bodies and thence to the plants (Figs. 1 and 2.) The trickling body consists of a capillary helix made of polypropylene which can be mounted on the lateral wiLhout cutting the pipe. The rate of application is controlled by the number of windings of the trickling body. This method ol' irrigation has been developed first in Israel, but is used extensively in Australia, in the US and recently also in Italy. Experiments have been started also in Hungary in some branches of fruit growing in open orchards (vineyards, strawberry, peach and apple orchards) as well as in closed farming installations. Horcher, F., Civ. Engr. : Wind -generated waves in minor canals (For the Hungarian text see pp. 355) A method is described l'or estimating the wave height needed for determining the freeboard allowance between the highest operating watcrlevel and the embankment crest in the case of minor irrigation canals. Under a study program on the experimental reach of the principal canal of the К. IV. irrigation section (Figs. 1 and 2) two wave recorders (Figs. 3 and 4) 8*