نشریه سد و نیروگاه برق آبی ایران
پیاپی 28 (بهار 1400)

In this study, a Darrieus hydraulic turbine for power generation applications is chosen and the response surface methodology (RSM) based on central composite design (CCD) is applied to obtain the optimized design for its hydrofoil geometry to increase the torque coefficient. For this aim, all turbine performance factors, except hydrofoil geometry, were considered to be constant and the turbine torque coefficient was estimated as a function of hydrofoil geometry using Parsec hydrofoil function by CCD technique. Optimized geometry of the turbine blade is the maximum points of the proposed function by RSM. To determine the turbine torque coefficient, two dimensional and transient numerical simulation for incompressible fluid flow using finite volume method is considered. Results show that the optimized geometry increases the torque coefficient about four percentages.

In this study, the discharge coefficient of side weirs located on converging channels was simulated for the first time using a new method of Extreme Learning Machine (ELM). To examine the accuracy of the numerical model, the Monte Carlo simulations were used and the experimental values validation was conducted by the k-fold cross validation method. Then, the input parameters were detected for simulating the discharge coefficient. Subsequently, the number of the Extreme Learning Machine hidden layer neurons was determined using a trial and error process. In the next step, the most optimized activation function was also obtained. Then, using the input parameters, six ELM models were developed and the superior model and the most effective input parameter were identified through a sensitivity analysis. The superior model estimated the discharge coefficient values with an acceptable accuracy. For example, the values of the indices R2 and MAPE for this model were estimated 0.963 and 5.135, respectively and the Froude number at the downstream of the side weir (Fd) was introduced as the most effective parameter. Then, a relationship was provided for the superior model.

In RCC dams, usually large amounts of concrete are poured in a short time that the heat generated by the cement hydration has led to an increase in temperature in the dam body.In this research, Abacus software, which is a finite element software, has been used for thermal analysis of the dam during construction and concreting. This is how thermal changes are applied. For the structure of 50 cm layers, it is assumed that each layer takes up 72 hours of analysis time. In general, the problem under analysis is analyzed 12 times. Each analysis is considered based on the start of the project from different months of the year, thus collecting information and using the perceptron network algorithm to the optimal time to build based on the maximum temperature in the concrete of the dam and the stresses created by it. Using perceptron algorithm and machine training with the data of 12 analyzes performed, the output for 365 days of the year as the start time of the production project and finally the optimal time to start the construction of the dam was obtained.

The main goal of preset research is investigate the effects of vertical component of Near-Fault and Far-Field earthquake records on the probability of overtopping induced damage of earth dam due to the reduction of freeboard due to the settlement of dam crest. In this respect 12 different earthquake record are selected. Nonlinear dynamic analysis of earth dam is implemented with FLAC 3D using Finn model that relates the increment of volume decrease per cycle of shear strain to the cyclic shear strain amplitude for considering the pore pressure build-up during seismic loading. Obtained results show that the response of dam for near-fault earthquakes considerably is larger than far-field records. Applying vertical component of earthquakes in the dynamic analysis caused the horizontal maximum displacement of damchr  crest increase 5.58% for near-fault records and 2.96 % for far-field records and also maximum settlement for damchr crest increase 31.69 % for near-fault records and 73.65 % for far-field records with including vertical component of records in the dynamic analysis, Also can be get form obtained results the damage probability of dam with considering vertical component of earthquakes is increase 249% for near-fault records and increase 2419% for far-field records.

Recently pianokey weirs become important in hydraulic structures. In this paper effect of the number of cycles on the flow of pianokey sideweir has been investigated experimentally. 45 experiments on single, two, four, six cycles pianokey and sharp crest linear weir on different heads (H/P = 0.3, 0.5, 0.65, 0.85 and 1) has been conducted. The input flow rate to the main channel was applied in such a way that the flow in this channel became subcritical. Experiments are conducted for different heads in order to determine the surface water profile and discharge coefficient. At the beginning of the opening, the height of water decrease significantly and as the number of cycles increases, this decrease further so that in 6 cycle water reduction is 5 percent more than 1 cycle. Discharge coefficient of the weir decreases with increasing the number of cycles in a constant effective length of the weir from 5 to 21 percentages. The ratio of discharge coefficient of the TPKWs to the rectangular sharp crest weir, was between 1.15 and 1.75. Experimental results show that the discharge coefficient of inertial weirs are larger than inverted ones but this difference is not significant.

Effective implementation of managerial systems needs software and hardware requirements. Project management competencies of the managers is one of the most important and inevitable requirements to ensure the success of the projects in any industry. Inorder to clarify the requirements, many international and professional instituts have presented well-known frameworks to help the managers to shape their management styles and action plans. For instance, Project Management Institute (PMI) based on ten knowledge areas indroduce project management processes and publish them in the book named: PMBOK. Intenational Project Management Assosiation (IPMA) with regared to the competencies present the most important project management competencies and publish them in the book named: ICB. With respect to the two mentioned standard the objective of this study is to show the relationship between project management competencies and project management processes. In this study a closed questionary was designed and distributed among 100 project managers and professionals. This research is implemented in one of the governmental company which is affiliated to the ministry of energy, responsile to construct macro hydropower plants. This study showed and proved the relationships between PM competencies and PM processes.

Population growth, growing scarcity of freshwater resources and food security have convinced all operators that spending large sums of money on cross-cutting responses to water, energy and food needs, especially in the face of climate change and global warming, is unreasonable.According to the latest classification of the International Geographical Organization, Iran is located in the category of arid and semi-arid regions and the city of Varamin is one of the driest regions of the country and faces the challenge of water scarcity. The increase in pollutants from energy production and consumption and its effects on climate and water resources has highlighted the importance of using cross-sectoral management in water, energy, food and water-focused issues.Lack of efficient management has sometimes led to increased tensions in each water-focused sector as well as rising costs. The purpose of this study is to identify and evaluate the potential of water, energy and agriculture resources in Varamin city, within the framework of the principles of sustainable development with a correlated approach of water, energy and food.