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Kazem Esmaili

    Kazem Esmaili

    Weirs are the most common structures for discharge measurement in engineering research. Streamline curvature, non hydrostatic pressure distribution on weir and nappe adherence to the weir lead to differences between calculated and... more
    Weirs are the most common structures for discharge measurement in engineering research. Streamline curvature, non hydrostatic pressure distribution on weir and nappe adherence to the weir lead to differences between calculated and measured discharges. Thus discharge coefficient, which is the ratio of real and theoretic discharges, is usually less than unity. In circular weirs the pressure distribution and velocity differs from sharp crested weirs which affect on flow discharge and extend the discharge coefficient more than unity. In this study, pressure distribution and velocity of different circular weir measured in laboratory models and compared with Fluent simulation as a numerical code. The results showed significant relation between measured and simulated data. Also it is found that the critical flow depth and separated flow are located respectively before and after the crest of weir. Nappe separation depends on overflow discharge and will shift to the downstream face of the cy...
    Collection of surface and subsurface waters in small seasonal rivers is very crucial, particularly in dry seasons. In this study a kind of intakes introduced, the system acts as a river drainage network. In this study an experimental... more
    Collection of surface and subsurface waters in small seasonal rivers is very crucial, particularly in dry seasons. In this study a kind of intakes introduced, the system acts as a river drainage network. In this study an experimental model of the subsurface intake was constructed and the effective parameters such as upstream discharge, installation depth, and drains interval were evaluated. The results showed that the water diversion mostly influenced by the upstream flow rate. The very small drain interval caused the discharge of each drain to be reduced. It was also revealed that the total drained discharge in the very transmitting media was mostly controlled with the number of drain and drain interval did have a marginal effect. Finally the regression equations were established to estimate the discharge of each drain based on dimensional analysis, which facilitate the design of this structure. Keyword: subsurface intake, porous media, drainage system, design criteria
    یبآ زاین نیمأت یارب ار یرایسب یاه هنیزه یرشب عماوج هزورما ندناسر لقادح هب و دوس ندناسر رثکادح هب فده اب دوخ شهاک اب ،دشاب هنیزه شهاک فده رگا .دننک یم فرص هنیزه بآ راشف هک یروط هب هکبش رد هدافتسا دروم یاه هلول هنیزه ،دشابن رتمک بآ رتم 14... more
    یبآ زاین نیمأت یارب ار یرایسب یاه هنیزه یرشب عماوج هزورما ندناسر لقادح هب و دوس ندناسر رثکادح هب فده اب دوخ شهاک اب ،دشاب هنیزه شهاک فده رگا .دننک یم فرص هنیزه بآ راشف هک یروط هب هکبش رد هدافتسا دروم یاه هلول هنیزه ،دشابن رتمک بآ رتم 14 ینعی دوخ نییاپ دح زا اه هرگ رد شهوژپ نیا رد .دش دهاوخ نیمأت فده نیا زا یا هدمع شخب عیزوت هکبش زا یشخب هروظنمود فده عبات ساسارب یزاس هنیهب هتفرگ رارق یسررب دروم نامرک ناتسا رد عقاو رهشامه بآ .تسا تیمها زیاح هقطنم صاخ میلقا هب هجوت اب هک تسا ،هلأسم یلام دعب رب هولاع بآ عیزوت هکبش کی یزاس هنیهب رد رد هک اه هلول رد بآ تعرس ،راشف نوچمه یرگید داعبا هب دیاب دعب قیقحت نیا رد .درک هجوت دراد یساسا شقن هکبش یحارط دیق ناونع هب تعرس لامعا و مود فده عبات ناونع هب راشف فده عبات هکبش نیا رد رگا .تسا هدش هتفرگ رظن رد تیدودحم نیمأت ظاحل زا هکبش دوش هتفرگ رظن رد هنیزه ساسا رب اهنت .دش دهاوخ هجاوم لکشم اب فرصم یاه لحم رد بسانم راشف Waterدم طسوت عیزوت هکبش هعلاطم نیا رد روظنم نیدب ل متیروگلا زا هدافتسا اب دعب و هدش یکیلوردیه لیلحت GEMS زا یزاس هنیهب نایاپ رد .تسا هتفرگ م...
    Sediment motion behaviour plays an essential role in sediment and hydraulic engineering, though its physics is still not fully understood. Ignoring the stochastic nature of the sediment transport leads to various equations for bedload... more
    Sediment motion behaviour plays an essential role in sediment and hydraulic engineering, though its physics is still not fully understood. Ignoring the stochastic nature of the sediment transport leads to various equations for bedload transport which are now being challenged due to their results. In this study, the non-suspended particle motion (bedload transport) in different hydraulic conditions was assessed by a particle tracking technique called Particle Tracking Velocimetry (PTV). The results of the PTV were applied to describe the particle behaviour throughout the probability distribution functions. Knowing the particle motion behaviour would guide learning more about the parameter/s governing the particle transport in different sediment transport regimes. The instantaneous particle velocity was measured after calibrating and validating the frames (resulted from the PTV). Different probability distribution functions were assessed with the Kolmogorov-Smirnov criterion (in 5 per...
    The drying of lakes and wetlands is a significant challenge to the hydrological cycle of resources, to human life, and to animal and plant species. The bed soils of lakes in arid and semi-arid regions become dry and wet due to various... more
    The drying of lakes and wetlands is a significant challenge to the hydrological cycle of resources, to human life, and to animal and plant species. The bed soils of lakes in arid and semi-arid regions become dry and wet due to various factors, such as global warming, which decrease and increase water levels in lakes. Therefore, field measurements and surveys are necessary in the localities of these natural ecosystems and can improve the management and protective measures against various hazardous processes including wind-driven soil erosion in these areas. The purpose of this research was to evaluate the soil erosion potential of Lake Bazangan, a natural lake located in the province of Khorasan Razavi, Iran. Experiments of soil properties were performed to study the rate of soil wind erosion. Wind tunnels were used to model the airflow. The results showed that the clay particle content significantly reduced soil wind erosion rates. Because of SAR's effect on the dispersion of cl...
    The high energy impinging on the outflow through the overflows is controlled by the design of the energy absorber structures in the downstream or downstream relaxation pool. However, the occurrence of downstream local scour is one of the... more
    The high energy impinging on the outflow through the overflows is controlled by the design of the energy absorber structures in the downstream or downstream relaxation pool. However, the occurrence of downstream local scour is one of the major threats to the stability of the overflows. In the present laboratory research, first, by conducting control experiments (unimpeded shot) at different landing numbers, the geometry of the scour pit was investigated, then by providing a basic block-height protection method in three geometric shapes (Rectangular, Semicircular, Triangle), four mounting positions proportional to the total Lb/Lf shot length (0.2, 0.4, 0.6, 0.8) and also, to concave the installation of blocks, the dimensions of the scour pit are measured and Dimensional analysis was performed using PieBuckingham method. The results showed; The use of block base on the slope of the shot in all the models tested has an effect on the dimensionality of the scour and has always reduced th...
    Due to streamline curvature, non-hydrostatic pressure distribution, and nappe adherence on the weir wall, the discharge coefficient of weirs is less than 1.0. However, in cylindrical weirs, the discharge coefficient extends to values more... more
    Due to streamline curvature, non-hydrostatic pressure distribution, and nappe adherence on the weir wall, the discharge coefficient of weirs is less than 1.0. However, in cylindrical weirs, the discharge coefficient extends to values more than 1.0 due to the different pressures and velocity distributions. In this study, pressure and velocity distributions of different circular weirs are simulated by computational fluid dynamics (CFD) and Fluent software and compared with experimental results. The numerical results of CFD show a significant correlation with measured data from manometers and a laser Doppler velocimeter (LDV). Experimental observations show that the critical flow depth forms before and after the crest for greater and smaller discharge coefficients, respectively. Nappe separation depends on overflow discharge and will shift to the downstream face of the cylinder in high discharges. To recognize the location of critical flow and nappe separation, analytical formulations ...
    The Symbiotic Organisms Search Algorithm (SOS) is used as an algorithm based on the social behavior of Symbiotic Organisms in optimization of Non-linear 5 model parameters for flood routing. The data used in this article is 4 day... more
    The Symbiotic Organisms Search Algorithm (SOS) is used as an algorithm based on the social behavior of Symbiotic Organisms in optimization of Non-linear 5 model parameters for flood routing. The data used in this article is 4 day observations from 30 November 2008 to 3 December 2008, which is located between the Molasani, and Ahwaz station on the Karun River. The time series data used included river inflow, storage volume, and river outflow. The results of the developed model with the Symbiotic Organisms Search Algorithm (SOS) were compared with the other Evolutionary algorithms including Genetic Algorithm (GA, and Harmony Search Algorithm (HS). The analysis showed that the best solutions achieved from the objective function by the SOS, GA, and HS algorithms were 143052.02, 143252.35, and 142952.45, respectively. The processes of these datasets determined that the SOS algorithm was premiere to GA, and HS algorithms on the optimal flood routing river problem.• In this article applied the Symbiotic Organisms Search Algorithm for Estimation of nonlinear parameters of the Muskingum hydrologic model of the Karun River located in Iran.• This method can be useful for managers of water, and wastewater companies, water resource facilities for predicting the flood process downstream of the rivers.• The present algorithm performs better than the other algorithms in the discussion of the optimization of Nonlinear 5 parameters of Muskingum model in flood routing.
    AbstractIn this study, the characteristics of sediment deposition with three levels of wastewater, different shear stress, and initial sediment concentration were investigated in an annular flume. ...
    The energy dissipation in a gabion stepped spillway is compared with that of a rigid structure. The prototype had one, two or three steps, and models of rigid and gabion spillways with similar geometric dimensions were tested. The results... more
    The energy dissipation in a gabion stepped spillway is compared with that of a rigid structure. The prototype had one, two or three steps, and models of rigid and gabion spillways with similar geometric dimensions were tested. The results showed that stepped gabion structures in one, two and three step modes, on average, increase the energy dissipation as compared with the rigid structures. In addition, the increase in flow rate reduced the efficiency of energy dissipation. Furthermore, in gabion spillways increasing the number of steps to three increased the energy dissipation. The effect of the second step on the rate of increase in the efficiency of energy dissipation was higher than the third step. The results indicated the high impact of throughflow in the gabion spillways on the energy dissipation. The second and third steps increased the energy dissipations compared to the one-step spillways; however, in the third step, the energy dissipations decreased slightly.
    Abstract The classical sharp-crested weirs are not suitable to implement in irrigation canals with high suspended sediment flow. Over the time, sediment deposition occurs in the upstream of sharp-crested weirs and causes a time variant... more
    Abstract The classical sharp-crested weirs are not suitable to implement in irrigation canals with high suspended sediment flow. Over the time, sediment deposition occurs in the upstream of sharp-crested weirs and causes a time variant water level raise in the upstream and consequently variable discharge coefficients. A series of laboratory experiments was carried out to test the hypothesis of strong turbulent formation and three-dimensional flow in the upstream of half-cosine sharp-crested weirs to prevent sediment deposition. To verify this hypothesis, a series of laboratory experiment was carried out for different weir heights and top widths in free and submerged flow conditions. Mean flow structure and turbulent characteristics of half-cosine and rectangular sharp-crested weirs were measured using a micro-Acoustic Doppler Velocimeter (ADV) probe. It was found that the streamwise velocities of half-cosine weirs were higher than the corresponding rectangular weirs, however, the velocity fluctuations in this direction were similar for both types of weirs. Velocity fluctuations in vertical and transverse directions were found to be significant in half-cosine weirs. The results showed higher turbulent kinetic energy below the crest level for half-cosine weirs which made them capable of sediment resuspension and sediment removal. In was found that the introduced weir model are suitable structures for passage of small floating debris and sediments. A head-discharge formulation was also developed based on the geometry of half-cosine weir in free flow and a constant discharge coefficient was obtained by solving the Fresnel integrals. For practical purposes, semi-empirical formulations were also developed to estimate flow discharge in both free and submerged flow conditions.
    In this study, The Spotted hyena optimizer Algorithm (SHO) is used to optimize the parameters of the Non-linear type 6 Muskingum model for flood routing. To evaluate the performance of the SHO in the Non-linear Muskingum models, The... more
    In this study, The Spotted hyena optimizer Algorithm (SHO) is used to optimize the parameters of the Non-linear type 6 Muskingum model for flood routing. To evaluate the performance of the SHO in the Non-linear Muskingum models, The Wilson River and the Wye River are applied by many researchers for validation. Moreover, in these studies, the Non-linear Muskingum parameters were estimated by the SHO Algorithm. The SSQ and DPO were considered as objective functions between computed and observed data. According to the results of Wilson river flood, the values of these objective functions for the NL3 model are 128.781, and 0.92 m3/s, and for the NL6 model, are 3.20 and 0.027, respectively. The results of the Wye River flood with the SHO showed that the SSQ and DPO for the NL3 model are 34789.39 and 90.05, and for the NL6 model are 30812.07 and 72.35, respectively. The results show that the proposed algorithm can be applied confidently to estimate the parameter optimal values of the nonl...
    Compound channels are hydraulic sections that consist of two parts including the main channel and the floodplain. The main channel conveys the usual runoffs and the basic discharge that often flows in the river. Predicting the flow... more
    Compound channels are hydraulic sections that consist of two parts including the main channel and the floodplain. The main channel conveys the usual runoffs and the basic discharge that often flows in the river. Predicting the flow characteristics in the prismatic compound channels includes the effect of the interaction between a fast flow in the main channel and a slower one in the floodplains. This speed difference creates a shear layer at the interface between the main channel and the floodplain, which results in the exchange of the size of the movement between the main channel and the floodplains. The result is a reduction in the flow-conveyance capacity of the main channel and its increase in the floodplains, which should be considered in flow modeling. On the other hand, Flow3D software is a great software for Computational Fluid Dynamics that is used to solve complex geometry problems. The main objective of this study is to evaluate the Flow3D model in numerical simulation of behavior of hydraulic flow characteristics such as velocity distribution, shear stress distribution and in prismatic compound channels. In this study, Volume of Fluid Method (VOF) was used to simulate water surface profiles and the dimensional Buckingham π theorem was used to extract parameters without effective dimension; besides, the model’s precision was tested by an experimental analysis in a rectangular flume. The results showed that the Flow3D numerical model has high accuracy in computing the flow passing the prismatic.
    Scoure is the removal of particle sediment which results variation of flow pattern. Local scour is considered as one of the reasons of instability and ultimately failure of bridges.Therefore, proposing some controlling methods to reduce... more
    Scoure is the removal of particle sediment which results variation of flow pattern. Local scour is considered as one of the reasons of instability and ultimately failure of bridges.Therefore, proposing some controlling methods to reduce this phenomenon is essential. In the study, effects of two types of squar and circular collar on a single cylindrical model have been investigated. In the next step by providing a slot through the pier and combination of collar and slot was used to investigate the scouring reduction. The results showed that use of both collar, specically below bed level decreased the scour depth. Square collar was more effective than circular in decreasing the scour depth. Combination of slot and collar on the pier could further reduce the scouring depth in which a square collar with W/D=2.5 in the bed with a slot near the bed reduce scouring depth up to 80 percent consequence.
    Citation:Farahi G, Khodashenas SR, Ghahraman B, et al. Flood inundation extent in storage cell mode. Sci China Ser E-Tech Sci, 2009, 52(11): 3376―3381, doi: 10.1007/s11431-009-0371 -2 ... Flood inundation extent in storage cell mode ...... more
    Citation:Farahi G, Khodashenas SR, Ghahraman B, et al. Flood inundation extent in storage cell mode. Sci China Ser E-Tech Sci, 2009, 52(11): 3376―3381, doi: 10.1007/s11431-009-0371 -2 ... Flood inundation extent in storage cell mode ... G. Farahi, Saeed Reza ...
    Due to streamline curvature, non-hydrostatic pressure distribution, and nappe adherence on the weir wall, the dis-charge coefficient of weirs is less than 1.0. However, in cylindrical weirs, the discharge coefficient extends to values... more
    Due to streamline curvature, non-hydrostatic pressure distribution, and nappe adherence on the weir wall, the dis-charge coefficient of weirs is less than 1.0. However, in cylindrical weirs, the discharge coefficient extends to values more than 1.0 due to the different pressures and velocity distributions. In this study, pressure and velocity distributions of different circular weirs are simulated by computational fluid dynamics (CFD) and Fluent software and compared with experimental results. The numerical results of CFD show a significant correlation with measured data from manometers and a laser Dop-pler velocimeter (LDV). Experimental observations show that the critical flow depth forms before and after the crest for greater and smaller discharge coefficients, respectively. Nappe separation depends on overflow discharge and will shift tothe downstream face of the cylinder in high discharges. To recognize the location of critical flow and nappe separation, ana-lytical formulations are proposed depending on weir size and inflow conditions. The results show good agreement betweenthe analytical predictions and experimental observations.