میرعلی محمدی

Flood plains of rivers play a significant role in the transfer of flood discharge. In this research, the vertical distribution of the longitudinal and transverse flow velocities and the amount of discharge passing through different sections of the main channel in flooded meandering rivers under the effect of the change in floodplain width and relative depth were investigated. Because the fact that the width of the floodplain is constantly changing along the river's path, in this article, from the four meandering compound channels with floodplain widths of 3.3, 4.31, 5.32, and 6.33 meters and three relative depths of 0.26, 0.35 and 0.45 were used. The results of the numerical simulation showed that with the increase in the width of the floodplain, the value of longitudinal and transverse flow velocities decreases and these changes in the transverse and longitudinal flow velocities are more noticeable due to the change in the width of the floodplain in the middle sections and above the overflow depth of the main channel, so that with the increase 92% of the width of the floodplain, the value of the maximum transverse and longitudinal flow velocity in the middle section decreases by 21% and 25%, respectively. Also, according to the results of this research, with a 92% increase in the width of the floodplain, the average flow velocity and discharge through different sections of the main channel will decrease by 24% and 33%, respectively.

Rivers as a natural drainage of a watershed have always been of interest in draining the runoff resulting from precipitation, especially during floods. Due to the formation of most cities and villages on the banks of rivers and the construction of structures in their floodplains, during floods, the pattern of river flow always undergoes changes, so it is necessary to study the interaction of flood flows of meandering compound channel in these areas. In this research, by using Flow3D software, which is a powerful software in the field of computational fluid dynamics, the flow structure and bed shear stress in meandering compound channel under the effect of structural density of floodplain during floods have been investigated. For this purpose, six types of structural density of 0, 8, 16, 11, 25 and 44% have been used on the floodplain using non-submerged blocks with distances of 7, 14, 21, 28 and 35 cm. The results of the numerical simulation showed that with the increase of structural density in the floodplain from zero to 44%, the average velocity of the main channel, the maximum water surface elevation and the amount of flow passing through the main channel increased by 51%, 25% and 84% respectively. Also, with the increase in structural density on the floodplain, the amount of bed shear stress has increased so that the maximum bed shear stress has increased from 1.32 to 4.61 pascal (250 percent) and moves towards the center of the main channel.

Due to the existence of various uncertainties in the materials and modeling of these structures, the quantification of these uncertainties requires sensitivity analysis and reducing the number of variable parameters to reduce cost and time in modeling. In this research, numerical analysis of Maku dam located in West Azerbaijan province which is considered as a case study is performed using FLAC2D software and the static response is obtained. The effect of construction layers and the amount and shape of contours of stress and displacement were compared and validated with previous researches. The 49 random variables (RVs) (of materials properties in the zones of the core, shell, filter, drainage, alluvium and bedrock) was considered. By performing sensitivity analysis and using the Tornado diagram, the number of variable parameters is reduced and 18 important RVs were identified for the modeling and analysis of the earth dam. The results showed that altering the dry density (γd) of the shell causes a change of about 8% and altering the Poisson's ratio (ν) and also the modulus of elasticity (E) of the core leads to a change of about 7% in earth dams’ response. Finally, parameters of dry density (γd), Poisson's ratio (ν), modulus of elasticity (E) and internal friction angle (ϕ) were identified as more sensitive parameters that have the greatest impact on the response of earth dams.

Failure to define the indicators and sub-indicators for measuring the performance of Repair and Maintenance (R&M) activities is one of the significant issues in a building to increase its life expectancy. Evaluation of R&M system in a building is one of the key factors in improving the quality of R&M performance steps. Therefore, to implement appropriate strategies, the criteria affecting on R&M system must be identified. Also, choosing the proper net policy is a strategic decision-making problem that effectively reduces the cost and longevity of buildings. In this research, by using the experts’ opinion and the Delphi method, the indicators and sub-indicators affecting the R&M system were identified, and those indicators were graded using the decision tool. The existing buildings in Karaj city as a case study were then considered to evaluate the proposed system. Analysis of the results shows that the safety index has the highest grade according to the experts’ opinion, but by reviewing the results of the case study, this rank was assigned to the health criterion. Then, by using the SWARA technique, the most critical policies affecting buildings’ R&M are identified among Emergency Maintenance (EM), Breakdown Maintenance, Corrective Maintenance (CM), Preventive Maintenance (PM), Predictive Maintenance (PdM), Total Productive Maintenance (TPM), Proactive maintenance. Applying the VIKOR method and the results of both approaches revealed that Corrective Maintenance (CM) and Breakdown Maintenance (BM) policies are the best for buildings, R&M policies.

Experimental investigation of embankment dams due to overtopping breach is a remarkable subject because it is the most possible failure reason, and it includes a complicated process. The mentioned phenomenon physical modeling has performed at energy ministry water research institute, hydraulics laboratory, and its hydraulic outputs compared with a benchmark model outcome in three scenarios framework. The results reveal that the breach process of physical models comprises three stages: i.e., initiation, development, and the end. Also, the development time is longer than that of the other stages. In first scenario, when shell gradation  varied from 0.5mm to 1.7mm, 26 percent of peak discharge increased and 14 percent of breach time decreased. In second scenario in which lake water level maintained at overtopping threshold for two hours (for more saturation), 15 percent of peak discharge and 14 percent of breach time declined. In third scenario where the primary breach groove did not excavate, the highest difference in comparison with benchmark model results occurred, when 34 percent of peak discharge grew and 24 percent of breach time reduced. Moreover, asymmetrical sedimentation pattern happened in the last scenario. The Calculation of eroded material volume and mass was sedimentation pattern determination harvest. Herein, the simultaneous measurements of breach geometry, flow hydrograph, and final sedimentation pattern are the research unique achievements. However, further acquired analysis would be influential for the embankment dam's failure phenomenon management.

The volume of sediment transport rate during floods is one of the important issues in river engineering. This volume of sediments has caused countless damages to the hydraulic structures which are built along the rivers, every year. The purpose of this study was to investigate the effects of hydrograph unsteadiness parameter on bedload transport rate. For this purpose, a real unsteady flow hydrograph was created inside a 15 m long tilting flume by installing an interface board between the computer and the pump inverter. 20 cases of hydrographs with different unsteadiness parameters were tested and the scour rate was obtained during the hydrograph time. The results indicate that the maximum scouring rate always occurs near the peak of the flood hydrograph and the time lag between them was positive. For hydrographs with the same peak and different base time, the maximum scouring rate occurs in the hydrograph with more unsteadiness. The maximum scouring rate of the bed has a direct relationship with the unsteadiness parameter, and it can be said that an 88% decrease in the flow unsteadiness parameter leads to a 76% decrease in the maximum bedload rate. Also, the scour rate in the ascending limb of the hydrograph is higher than the descending limb, which by reducing the unsteadiness parameter, the distance between the limbs in the sediment hysteresis diagram decreases.

Natural rivers experience significant sediment transport rates during floods.The purpose of this study was to investigate the effects of flood hydrograph intensity parameter on the amount of bed sediment transport rate. For this purpose, a real unsteady flow hydrograph was created inside a 15 meters long tilting flume by installing an interface board between the computer and the pump inverter. Sediments with a d50 of 2.69 mm have been put uniformly on the bottom of the channel and the flood hydrograph has been applied on it after saturation. 20 cases of hydrographs with different intensity parameters were tested and the erosion rate was obtained during the hydrograph time. The results show that the maximum erosion rate always occurs near the peak of the flood hydrograph and the time delay between the peak of the flood hydrograph and the peak of the sediment hydrograph is mostly positive. The erosion rate in the rising limb of the hydrograph is higher than the falling limb, and the distance between them decreases in the hysteresis diagram as the flow intensity parameter decreases. The changes of bedload transport rate (qb) in terms of flow rate (Q) are clockwise hysteresis. By decreasing the hydrograph intensity parameter by 32, 57, 75 and 87%, the total volume of transferred sediments decreases by 27, 51, 78 and 90%, respectively. A 50% decrease in the base time of the hydrograph under the same conditions has caused a 46% decrease in the total volume of transported sediments.

The downstream scour of the vertical drop can be one of the causes of instability and failure of this structure. In the present study, the downstream scour depth of this structure predicted using the support vector machine (SVM) method. For this purpose, 104 experimental data used to estimate the scour depth. hese data are a function of the two dimensionless parameters of dansimetric Froude number (Frj) and tailwater depth (yt / yj) that have been entered into the SVM in three different models. To evaluate the results, the evaluation criteria of R2, NRMSE, DC, and MARE used. The results showed that model number (1) with the input combination (Frj and yt / yj) with R2 = 0.9777, DC = 0.929, NRMSE = 0.0775, and MARE = 11.89% for the test stage leads to the best result. The SVM method also has appropriate accuracy, acceptable results, and desirable performance in estimating the scour depth. Also, it was found that the densimetric froude number has a greater effect on estimating the relative scour depth compared to the tailwater depth.

Prediction of flow discharge coefficient, Cd, for a sluice gate under free and submerged flow conditions is one of the essential issues in hydraulics. In recent years, various semi-empirical equations have been developed in order to predict Cd for a sluice gate that application of those formulas under submerged flow conditions suffered from large errors. The aim of the present research is to use Gaussian Process Regression (GPR) and Support Vector Machine (SVM) used in soft computing techniques, so that estimating Cd in submerged flow conditions and comparing the results with quasi-experimental methods are of interest, herein. For this purpose, an experimental dataset comprised of 122 data points were used to feed the methods utilized. Different combinations of dimensionless parameters were then prepared and the performance of the afore mentioned methods were assessed. The results showed that SVM with input parameters of 𝑦𝑡⁄𝑤, 𝑦0⁄𝑤, 1/𝐹𝑟2 and S by the values of Root Mean Square Error (RMSE=0.017), correlation coefficient (R=0.97) and Nash-Sutcliffe Equivalent (NSE=0.95) had a better performance than GPR and other semi-empirical approaches, indeed.

In order to understand the mechanism of flow patterns in vegetated channels, the flow located in a rectangular channel was numerically investigated by using OpenFOAM software. Firstly, two solvers of that software (i.e. icoFoam and pimpleFoam) were used to calculate the velocity profiles in both longitudinal and cross-sectional directions for four selected sections in a rectangular channel with a square cylinder. By comparing the simulation results with the available data, the icoFoam solver with a better performance (six Percent Error) was selected for the next developed model. A new model was then created with two tandem square cylinders with spacing ratios of two and a half and five. Flow patterns, velocity distribution and pressure characteristics in the channel with different inlet flow velocities were investigated for two cases. It was observed that a flow field disturbance occurred in all simulations and the current changed from steady state to unsteady one at a critical velocity. This instability occurred in a distance between the cylinders for the spacing ratio of five at an average Reynolds number of eight, while for the ratio of two and a half it is occurred at an average Reynolds number of 32. The maximum values ​​of longitudinal and transverse velocity timelines in a period of 200 seconds for four states (including two Reynolds numbers and two different spacing ratios) were plotted in two spatial ranges and fully investigated. According to the results, it can be said that the overlap has an important role on the flow characteristics in tandem arrangements and by increasing the distance ratio between the cylinders by 55 percent, the critical velocity value decreases by 74 percent.

In many organizations, the selection of the project portfolio and activities related to the management of selected projects during their life cycle is one of the most important activities of the organization. Due to the financial and physical constraints of the projects, there are always many projects waiting to be implemented. Therefore, the selection of projects should be such that a project portfolio is selected and formed in an optimal time horizon for proper management. Regarding the position and nature of public-private partnership agreements in Iran, ten projects with public-private partnership agreements have been selected by given the objective function to maximize the net present value of the projects by simultaneously considering two factors of reinvestment strategy and time value of capital. Input data were entered into Excel software using formulas related to public-private partnership contract to specify economic parameters, complete the data and also prepare them. Then, the model is coded in Lingo software and executed to find the research results. This model has an objective function that shows the maximum net present value of projects selected as a case study of portfolio management based on specific start times. The results of this study are obtained in two cases, according to the amount of the objective function in the case with considering the reinvestment strategy and the time value of capital with the optimal time horizon obtained in this research for eleven years, compared to the value of the objective function with the same conditions, for the assumed 20-year time horizon, 257.59 billion rials have been saved in construction costs and also one year has been reduced from the completion of the construction of the project portfolio.

Evaluation of maintenance system in the building is one of the key factors in improving the quality of maintenance and repair processes. It can be stated with certainty that all buildings need maintenance and scientific and technical repair after construction, and therefore how to define this system and determine the appropriate indicators and strategies for it will play an important role in the cost and longevity of the building during operation. The purpose of this paper is to identify and prioritize the indicators affecting the maintenance and repair system (R&M) of Residential buildings and determine the most appropriate policy related to it using a combination of multi-criteria decision-making method. In the presented method, first the weight of the indicators was calculated and then the indicators were prioritized based on multi-criteria fuzzy and non-fuzzy decision-making methods.Finally, considering the ranks obtained from those methods, the final ranking of indicators was calculated using the Average rating and Copeland method. The results showed that the indicators of safety, health, accessibility and proper utilization are in the highest priority respectively and reliability are in the last rank. This issue indicates the importance of safety indicator in evaluating the maintenance and Repairs system of buildings. in order to perform maintenance and repair operations, by identifying and prioritizing effective indicators, they can be used to evaluate the maintenance and repair system of the building based on them.Finally, according to the results and with the help of ARAS method, Breakdown Maintenance Strategy was selected as the most appropriate maintenance policy for buildings.The results of this study show that the application of multi-criteria decision-making methods can help the construction industry professionals to select the key effective indicators in the repair and maintenance system and determine appropriate strategies. Finally, suggestions for future research were provided.

The study of annual damage statistics due to floods in Iran and the world shows the extent of flood damage to natural and human resources in different regions. Determining the flood zone of rivers in order to protect national resources and reduce flood damage provides the possibility of protecting the river from encroachment and the construction of any unauthorized facilities in it. Therefore, in the present study, the capability of numerical models in simulating the flood zone of rivers was evaluated in the range of Azarshahr Qushqura river and the two-dimensional hydraulic model HEC-RAS 5.0.7 and one-dimensional HEC-RAS model were compared. Changes in the hydraulic characteristics of the flood flow including depth and velocity of the flow at different cross sections of the models were evaluated. The results showed that the water surface level (flow depth) of the two-dimensional model HEC-RAS compared to the one-dimensional model had the lowest error as compared to other hydraulic parameters of flood flow. The two-dimensional HEC-RAS model showed the highest error rate in the flow velocity parameter in comparison to the one-dimensional model. The results indicated that two-dimensional HEC-RAS model V5.0.7 determined the surface of the flood zone 12.46 % more than the one-dimensional HEC-RAS model. The confirmation of the resulting zones on the current state of the river and comparison with the river aerial photo of 1346 indicated the higher accuracy of the two-dimensional HEC-RAS model in estimating the flood zone of the river.

The purpose of present research work is to study the hydraulic properties of River Simineh and its process using HEC-RAS model, in a combination with ArcGIS software using HEC-GeoRAS extension to simulate the hydraulic parameters of river having a catchment area of 3726 km2. For that mean, since multi-dimensional models require long time and high cost in river bends, by using a combination of satellite images and HEC-RAS model a multi-dimensional simulation was prepared. Among those, 58 cross-sections are considered along the river lane that main data required in this research are elevation maps, satellite images, boundary conditions and River Simineh hydrometric stations. The results showed that at the upstream of river, the discharge was 316.3 m3/s and water level was 12.85 m, and at the downstream the flow rate and water level are 313.6 m3/s and 11.52 m, respectively. On the other side of the river bend, the water level variation is around 50 cm and the flow velocity is directly proportion to a distance from the river bank; so that the maximum flow velocity of 2.2 m/s occurred at a distance nearby 1.5 m. To verifying the model, a statistical parameter of NSE coefficient for the water level and flow depth were 0.805 and 0.845, respectively; which shows the accuracy of model. Those results indicate a high accuracy of HEC-RAS model in hydraulic simulation of River Simineh flow. Also, simulations prepared in GIS background have significant impacts on the accuracy of outputs

Bridge piers, which are constructed across the rivers, are always prone to the erosion and scouring phenomena. Bed shear stress is one of the main factors of scouring around bridge piers in which there is a direct relationship between bed shear stress and scouring. In the present research work, firstly the laboratory results of cylindrical bridge piers were used for validation of the model, and then the effect of bridge pier’s shape on bed shear stress and other effective parameters were studied by numerical modeling and applying Flow-3D software. The cylinder pier experienced the highest amount of bed shear stress. In contrast, the case lenticular shape showed 26% reduction with cylinder shape occurs. The results show that different pier shapes have a perceptible effect on reducing the maximum amount of bed shear stress. This function affects streamlines around the bridge piers, and the formation, length, and power of wake and horseshoe vortexes. So that, streams having -0.1m/s behind the cylinder affected the length of 0.2m but in lenticular shape, 40% decrease appears. Additionally, the piers with a forehead causes a stronger down-flow. In those sections, because of the presence of horseshoe vortex, streamlines shift to the upstream, so that the negative velocity figures occur in this region.

Given the importance of the repair and maintenance process in keeping equipment and facilities ready for use, it is necessary to assess the process and performance of maintenance indicators regularly so that the repair and maintenance is planned and upgraded. The main purpose of the building repair and maintenance is to control the equipment, facilities, and various building components to determine productivity and optimize their ability to achieve the highest efficiency. As measuring the efficiency is one of the most important performance evaluation methods, evaluating the efficiency of the repair and maintenance is one of the qualitative factors to improve this system. The purpose of this study is to evaluate the efficiency and performance of the repair and maintenance in buildings using a quantitative and provable data envelopment analysis (DEA) method. The results of this study show that the DEA is a suitable method for evaluating the efficiency and productivity of the decision-making units (DMUs).Therefore, first, the questionnaire is formed based on the building repair and maintenance system parameters extracted from Topic 22 of the National Building Code, the ranks are determined, and the results obtained from the sub-indices are integrated by the mean ranking index, and the qestionnaires’ reliability is measured using Cronbach's alpha. Finally, after defining the input and output indices by the DEA, the efficiency of each building and its cost are determined based on the repair and maintenance indices(In a case study of the city of Karaj). The results showed that the minimum and maximum reduction of the cost of charging, maintenance and repair of the building to convert them into an efficient building is 1% and 80%, respectively. Moreover, based on the results, it is possible to provide suggestions to improve the efficiency of the inefficient buildings based on the repair and maintenance costs.

The study of behavior of water level fluctuations is important for water balance due to the unbalanced distribution in the hydrological cycle. In present study, the groundwater level fluctuations of Urmia and Miandoab plains in two models SVM and Wavelet from the group of soft calculations have been investigated. For this purpose, information about the period years of 1381-1386 for both plains of Urmia and Miandoab by considering four scenarios of groundwater level -groundwater level with a delay of one month, groundwater level -groundwater level with a delay of two months, Groundwater level -precipitation and groundwater level -temperature. The simulation results were compared and the best model was introduced. The results of regression analysis showed that R2=0.9 and MSE=0.4 belong to the second piezometer well of Urmia plain and the third piezometer well of Miandoab plain in both SVM and Wavelet models for 3 scenarios of groundwater level -groundwater level with a delay of one month, Groundwater level was precipitation and groundwater level was temperature. Data on climatic variables of temperature, precipitation and groundwater level with a delay of one month as an independent variable and groundwater level data as a dependent variable formed the mentioned scenarios with 80% of educational data and 20% of test data. The results showed that the climatic variable of precipitation has a significant effect on groundwater level fluctuations. In general, the prediction results of Wavelet model were better than SVM model in investigating groundwater level fluctuations in Urmia and Miandoab plains. In the present study, an independent study of the mentioned models in order to simulate groundwater level fluctuations and compare each of the two models in their application.

The occurrence of oil spills in the seas and oceans causes many short-term and long-term damages to the coasts and marine ecosystems. Therefore, in order to reduce the damage, comprehensive coastal vulnerability maps can be provided to coastal management decision-makers as well as the emergency response team as a powerful tool. In the present study, by combining the mathematical model of oil slick routing and ArcGIS software, the northern coasts of the Persian Gulf were evaluated based on exposure to oil pollution. For this purpose, 20 hypothetical fall scenarios with oil type and time of random occurrence in summer and winter were designed. Then, using GNOME Lagrangian software, the path of the oil slick and its arrival time to the shores were simulated, and based on that, the matrix of exposure of each coastal area to pollution was formed. Finally, the northern shores of the Gulf were classified into five levels of vulnerability. The results showed that in summer Assaluyeh and Bushehr ports with a cumulative probability of 120 and 94%, respectively, and in winter Assaluyeh port with a cumulative probability of 119% in all scenarios were in a very high vulnerability. In addition, the ports of Bushehr and Assaluyeh had the highest potential for damage to the region. According to the results of this study, coastal vulnerability is significantly affected by seasonal changes in climatic conditions and flow conditions.

Applying the studies of resistance to flow in open channels and rivers with specific properties in order to manage them is necessary. An optimum and proper foresight of resistance to flow has a direct impact on the estimation of flow rate, which is important factors in decision about hydro-project developments. This research work tries to identify items which are influencing on the flow resistance by handling properties of the river in specific intervals. In this study, the best Manning’s coefficient of “Shahar-Chay” river by means of hydraulic characteristics and aggregation of river bed has been estimated. Manning’s coefficient by using several methods and using pictures and properties of a river reach with a specific Manning’s coefficient, by comparing to the river conditions with relative pictures and estimating approximate range of the Manning roughness coefficient has been verified. By preparing 3D drawings from region using Arc-GIS and creating lateral sections using Hec-GeoRas, geometric specifications of “Shahar-Chay” river used as input in order to complete hydraulic simulation of HEC-RAS model. By running the software for different values of Manning’s coefficient and hydraulic specifications output from modeling compared to the hydraulic specifications collected from the river reach area. It is found that the most proper value for the Manning coefficient at “Keshtiban” reach is about 0.032. The results of the present research work reveals that three methods, namely “Chaw”, “Coawn” and “comparison of pictures” are more accurate for estimating Manning’s roughness coefficient in rivers, because of introducing several factors taking into account.

Nowadays, extraction of materials from river bed is one of the effective factors in the occurrence of scouring phenomena around bridge piers. The extent of scouring around the bridges depends on a number of factors, including the type of foundation, the Froude number, flow rates and bed granulation. In , in vitro evaluation of scouring around piers groups in two different grains was investigated. The effect of scouring and armoring of scours in scouring control was investigated in both natural and river conditions. In the present study, 44 experiments with identical laboratory conditions were tested in a rectangular channel with of 13 m, width of 1.2 m and depth of 0.8 m. In this study, 44 experiments were conducted in two models 1 (control or simple groups) and model 2 (modified groups), both scaling behavior. B = 0.7) and Bꞌꞌ (= 1.7 mm) were analyzed. In addition, to investigate the effect of material extraction on the scour rate of bridge pedestals, experiments were conducted for both pit-bed (pit-extraction mode) and pit-free bed (river natural state). A removable sand bed with a height of 22 cm was placed between the floorboards. Two series of pedestals were located upstream and downstream of the bed with a clear distance from the flooring. The pedestals were arranged in the same arrangement (consecutive tripods in the direction of flow and in the center of the channel width) with center to center 21 cm apart.   The results showed that the armed (rough) pier group was less than the simple pier group (flat surface), due to the excavation of river materials, it increased the scour equilibrium time. The armed pier group also controlled the impact of extraction of materials on the scour rate. By examining the upstream and downstream materials mining, it was observed that extraction of materials of upstream of pier group decreased and extraction of materials of downstream pier group increased the scour. Therefore, it can be concluded that the scouring of pier is more sensitive to the downstream pit hole and even the mining of materials from upstream of the pier should be possible. In other words, the percentage of scour depth reduction in downstream bed due to extraction of materials and percentage of scour depth in upstream bed of extraction of materials in model with armed pier group were higher and lower than model with simple pier group, respectively. The percentage of scour reduction due to armed of the pier was also studied and it was observed that at best, the maximum scour depth in the aggregate with mean diameters of 0.78 mm and 1.7 mm by armed pier group were 55 and 66 percent, respectively. It is also observed that the extraction of materials from the bed increases the equilibrium time. It should be noted that scour is balanced when the driving force is approximately equal to the resistive force (particle saturation weight). The results show that the presence of the pit leads to an increase in the scour equilibrium time. In other words, when the sediments reach the pit site, due to the decrease in water velocity and increasing depth, the flow cannot carry the larger sediments and the sediments settle in the upper wall of the pit.

Natural channels always form meanders along their path, and it is important to consider the effect of this meander on the flow characteristics pattern. When a flood occurs, the water level crosses the main section of the river and enters its floodplains. In this case, the river crossing becomes a compound cross-section. In this study, using the Flow3D software (powerful software in the field of computational fluid dynamics),  the vortex rotational power and transverse flow in the meandering compound channel under the influence of relative depth and Sinusoidal Change were investigated. For this purpose, six channels with different sinuosity and three relative depths were used. The results of the numerical simulation showed that the maximum rotational power of vortices increased with an average of about 195% by increasing the sinusoidal rate from 1 to 1.209. The maximum rotational strength of the vortices and the transverse flow rate occurred at a 45-degree angle to the central arc and a sinusoidal value of 1.209. In the main cross-section of the meandering compound channel, for all sinusoidal values, by decreasing the relative depth, the vortex and transverse rotation strengths increased and the rate of change in transverse current power relative to relative depth changes decreased with increasing sinusoidal rate.

In this research, using FLOW3D software, the flow velocity distribution and shear stress of the bed in meandering compound channels due to the change of floodplain width and relative depth were investigated. For this purpose, four sections of meandering compound channels with floodplain width having 3.3, 4.31, 5.32 and 6.33 meters and three relative depths of 0.26, 0.35 and 0.45 have been used. The results of numerical simulation show that by increasing the floodplain width, the depth averaged velocity and bed shear stress are reduced. So that with a 92% increase in floodplain width, the maximum flow velocity in the main channel decreases by 24% , and the depth averaged velocity at relative depths 0.45 and 0.26 are reduced by 17% and 21%, respectively; and the rate of change of depth averaged velocity is more noticeable due to a change in the width of floodplain for low relative depths. The effect of changing the floodplain width on the bed shear stress has the highest value in the mid-section between two apexes (CS3 section); so that by 92% increase in the floodplain width in the mid-section (CS3), the bed shear stress is reduced by 35%. Also, the amount of boundary shear stress in the inner arch wall in all channels which is higher than the boundary shear stress in the outer arch wall; and the maximum amount of wall shear stress occurs near the bankfull level of the main channel and by increasing the relative depth, the wall shear stress increases.

WaterGEMS software provides a numerical model which simulates different parameters in water supply systems based on the principles of hydraulics. The most remarkable chemical substance used in water refinement procedure is the chlorine. Hence, WaterGEMS software models the chlorine to detect its concentration in each pipes of the water supply system. If the chlorine concentration exceeds 3mg/lit, it would be dangerous for the Man health. In addition, the model may calculate water age in water supply networks. And more, the WaterGEMS can trace the chlorine substance as well. In this research, the chlorine concentration, water age and chlorine trace parameters have been simulated by WaterGEMS for a case study: Vahidieh district (located on the west part of Tehran province). Meanwhile, other quantitative items have also been calculated in Vahidieh water supply network system. For example, flow discharge, flow velocity, water head loss in pipe networks. This is because, there are important relationships between qualitative and quantitative parameters for the optimization design of water supply networks. For more comfortable comparison and interpretation of the above concept, three pipes in different places of Vahidieh water supply network have been chosen (i.e. 18th,168th and 293th pipes put in the left, middle and right side of water supply network, respectively). The innovation of present research work is to provide quantitative and qualitative items for the simulation of Vahidieh region where it has not yet been found out up to now. In addition, modeling of all mentioned items will result in a comprehensive view to the design of water supply networks. A miniature previous research work on the subject is mentioned. Aghasi (2018) who has presented a model by WaterGEMS to determine appropriate points for injecting of chlorine in a part of Mashhad water supply network. He concluded that the appropriate points for chlorine injection dependent upon the network geometry, pipes diameter and the pattern of consumption. Javadinejad et al. (2019) utilized a pump and gravitational statuses in Semirom water supply by using WaterGEMS. They stated that in pumping method, water qualitative management may guarantee a better system. Vidhi and Geeta (2019) simulated a rural region in India by WaterGEMS. They resolved that the remained chlorine concentration in the pipes are in standard status (i.e. less than 3mg/lit).

The WaterGEMS numerical model has been designed by Haestad Methods company. Meanwhile, it is dependent upon the American hydraulics council. In the software, the analysis of water distribution networks is given step by step as: firstly, network drawing based on the nodes coordinates, pipes situation, reservoirs, tanks and other elements. Secondly, defining the network hydraulic traits. Thirdly, defining the distribution network for a hydraulic performance. Fourthly, defining the network analysis method. After that by running the software, the network parameters are obtained. Finally, the network quantitative and qualitative results may be achieved. The Vahidieh town water supply network where used as a case study; its population will be 78600 person at the end of 30 years design period. In so, for the total consumption of water will be 215lit/day per capita. The amount of water consumption in the region has been estimated 195lit/s. There are 2 reservoirs and 2 tanks in the new water supply network system. Volume of each reservoir is 5000m^3 and the volume of each tank is 500m^3. Meanwhile, a chlorination house has been designed to disinfect the region water that the maximum chlorine injection will be 3mg/lit. The pipes material was polyethylene. For modeling Vahidieh town water distribution network by WaterGEMS software, first of all, the nodes and pipes are drawn by AutoCAD software. Secondly, the reformed information imports to the WaterGEMS software. In this step, it is necessary to extract nodes altitude codes from ArcView software. Thirdly, other elements of network, consumption pattern and different scenarios are defined. Finally, the software reports will be analyzed and the results are obtained.

In this paper, a successful simulation has been carried out of a water supply network using WaterGEMS software. The numerical simulation reproduced the complex flow patterns in the pipes network associated with a particular water consumption in the Vahidieh water supply network are presented as a case study. On the basis of the analysis made by applying WaterGEMS, the following results are obtained: The chlorine concentration in 18th, 168th and 293th pipes were selected and have been studied, in more detail. Meanwhile, three defined scenarios are used: (1). Primary concentration in reservoirs, tanks, pumps, valves and nodes are 2, 0.5, 1, 1, 0.1 mg/lit. (2). The chlorine concentration reaches to 10 mg/lit in reservoirs, while its concentration is the 1st scenario in other ingredients. (3). The chlorine concentration reaches to 5 mg/lit in tanks, while its concentration is the 2nd scenario in other ingredients. Based upon the numerical model reports in 18th pipe, water age is higher than that of 168th and 293th pipes. According to the Vahidieh town population distribution, less population surrounded by 18th pipe in comparison to the other two pipes. Plus, in 18th pipe, the maximum water age is 3 times of maximum water age in 168th pipe. According to the WaterGEMS reports, under the different scenarios, chlorine concentration in 168th pipe is equal to injected chlorine concentration to reservoirs (the pipe which is closer to reservoirs). In addition, 168th pipe chlorine concentration is 10% higher than the other two pipes under three scenarios. The chlorine concentration computation in the selected pipes indicates much higher influence on the reservoirs chlorine concentration on chlorine concentration in water supply network pipes. Furthermore, based on the third scenario, when the chlorine concentration increases in the tanks, there is not tangible variation in pipes chlorine concentration. The reason is that much higher volume of reservoirs in comparison with the tanks volume occurs. Based upon the obtained results from WaterGEMS reveals that in 18th pipe the maximum water provision probability from the 1st tank is about 45%. Additionally, 168th pipe water provision probability from two reservoirs is the same. Also, 293th pipe water has surely been supplied from 2nd tank. As well, flow velocity, water head loss and water discharge can be studied in each 24hour period based on hourly consumption pattern. Based on the WaterGEMS outputs, the maximum water flow velocity in 18th pipe is 0.3 m/s. This result is reasonable, because of water age item in the pipe which is higher than that of the other two pipes. As a consequent, it seems that sedimentation probably occurs along pipe 18th. Moreover, 168th pipe reaches a maximum head loss of 0.4 meter, and 293th pipe receives a maximum water discharge of 8lit/s.

Flow in compound sections, due to the differences in velocity between the main channel and floodplains, is structurally quite different from that in simple channel sections. In the present research work, FLOW3D software was applied in a rough rectangular compound channel with single floodplain. The model geometry was selected from the experimental channel by Bousmar (2002), and the numerical solution results were validated by comparing the depth-averaged velocity parameter. The purpose of this study was to investigate the effects of roughness, depth and relative width on flow velocity distribution, bed shear stress variation, and location of maximum stress in compound channel sections and simulated flow for 3 relative roughness values of 1, 2 and 2.9. Results showed that flow rate difference between the main channel and floodplain as the generator of shear stress and secondary flows in those sections increased by 3 times. Relative roughness for the Model A, 33.5% and for Model B, increased by 15.12%. While the relative depth parameter increased from 65% (from 0.2 to 0.33), the difference for the two models A and B decreased to 36.32% and 37.85%, respectively. So, it seems that using Model B is more appropriate for high relative roughness. Also, by increasing the relative depth from 0.2 to 0.33 in all the relative roughness values studied, the location of maximum shear stress for both models changed from the main channel to the floodplain.