Jalal Sadeghian; Mohammad Reza Mihani
Abstract
The hydrous bed of the rivers covered with coarse alluvial materials is a goodresource along with other resources to provide the needs of the water. Therefore,studying and investigating the flow behavior around wells excavated in these bedsand determining their discharge capacity is very important. Since ...
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The hydrous bed of the rivers covered with coarse alluvial materials is a goodresource along with other resources to provide the needs of the water. Therefore,studying and investigating the flow behavior around wells excavated in these bedsand determining their discharge capacity is very important. Since the flow to thewells is radial and previous research on coarse, porous media, there has beenmainly for parallel flows, and yet any equation replacing the Laplace relationship incoarse, porous media, is not provided for non-Darcy radial flows with a free surface,Therefore, the extraction of the differential equation ruling on these types of flowsin the cylindrical coordinates and a method for numerical solution of them in thisresearch has been followed. Based on the research carried out in this research, thepower (exponential) equation as the most suitable basic relation for the analysis ofradial flows was determined and used. Also, in order to solve the governingequations a numerical model was developed using finite volume method. Thedeveloped numerical model act well for the analysis of radial flows in the coarsealluvial beds. The results of the implementation of the numerical model indicate thatthe pressure distribution can be considered hydrostatic.
Majid Heydari; Jalal Sadeghian; Saeid Shabanlou
Abstract
Manning roughness coefficient is one of the most important parameters in designing water conveyance structures. Unsuitable selection of this coefficient brings up some mistakes. This research aims to present a method to determine the Manning roughness coefficient based on a combination of optimization ...
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Manning roughness coefficient is one of the most important parameters in designing water conveyance structures. Unsuitable selection of this coefficient brings up some mistakes. This research aims to present a method to determine the Manning roughness coefficient based on a combination of optimization algorithm of simulated annealing (SA) with gradually varied flow equations. Therefore, in a lab rectangular flume of 12 m, 60 cm and 65 cm in length, width and height with fixed channel bed slope of 0.0002, nine series of water level profiles were carried out. Then, an objective function based on observed and calculated water level gradient was defined to decide on manning roughness coefficient while it was minimized with simulated annealing optimization method. The values of objective function parameters were discussed by sensitivity analysis and the most optimal objective function was obtained. To measure the accuracy of coefficient obtained, Statistics indices of R2, Root mean square error (RMSE), Mean bias error (MBE), d were used. The results showed that manning roughness coefficient has a great accuracy.
