Resumen

KAYAL, Hamidreza  y  FAZELI, Meysam. Investigating the numerical modeling of the effect of direct and lateral congress overflows in channels on the discharge coefficient. J. Selva Andina Res. Soc. [online]. 2024, vol.15, n.1, pp.46-62.  Epub 29-Feb-2024. ISSN 2072-9294.  https://doi.org/10.36610/j.jsars.2024.150100046.

Congress overflows are economic structures to increase the output efficiency of the overflow in a limited width, which can be seen in the plan in the form of a trapezoid, triangle, etc. Increasing the overflow capacity by increasing its width is not always possible, the use of congress overflows is due to the increase of their effective length in hydraulic height and specific width. In this research, the effect of the geometric shape of concourse overflows in direct and lateral flow modes in channels is evaluat-ed. For this purpose, three rectangular, trapezoidal, and semicircular overflows have been chosen in such a way that their length is equal. These three spillways have been used in the direct and lateral paths after verification and calibration, and their discharge coefficients have been obtained. Flow3D software is used in numerical modeling. For validation and calibration, numerical modeling of direct sharp edge overflow and triangular and trapezoidal congressional shapes has been done and the results show a high 90 % agreement between numerical and laboratory results. After verification and calibra-tion, the above-mentioned congress overflows were used simultaneously in the direct and lateral paths. In all cases of discharge of the flow passing through the direct and lateral overflow obtained by using the relationship of overflows, the discharge coefficients were determined. The results of the numerical solution were verified with laboratory data to determine the flow rate of the overflow coefficient, which showed that there is a good match between the numerical and laboratory solutions and the Flow3D software has a high capability to simulate the flow on congressional overflows. The results show that under the same conditions and high flow rates, H/P > 0.2, the flow coefficient of congressional over-flows in the straight channel is about 0.8 and in the lateral state is about 0.7. Also, on average, the side overflow flow rate is calculated as 40 % of the total channel flow rate. The best performance is related to the trapezoidal overflow and also by increasing the flow rate, the effect of the overflow shape can be saved.

Palabras clave : Overflow geometry; discharge; direct and lateral congress; numerical model.

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