Ebrahim Jabbari

Iran University of Science and Technology · School of Civil Engineering

High-accurate streamflow data obtained from the Fluvial Acoustic Tomography (FAT) increase forecasting accuracy, especially in the case of short-term forecasting. The reason is due to the better temporal resolution and higher measurement frequency than the traditional Rating-Curve (RC) method. In this study, Multilayer GMDH Algorithm (MGA) and Comb...

Short-term forecasting of streamflow is one of the most important goals in water resources management and flood control. However, one of the problems that researchers always face in this type of prediction is the Lack of an accurate and high time resolution database. The Fluvial Acoustic Tomography (FAT) is an innovative method of data gathering wh...

با توجه به اهمیت فراوان پیش بینی نرخ جریان در مهندسی آب به منظور مدیریت بحران و کنترل منابع آب شناخت یک روش مناسب برای پیش بینی و عوامل مؤثر بر آن میتواند یک امر مهم باشد. یکی از عواملی که تأثیر زیادی بر دقت پیش بینی دارد بانک داده های ورودی می باشد. در این راستا میتوان با اسیتفاده از روش های نوین مانند تیکه نگاری صوتی یک بانک داده منظم و دقیق ایجا...

Prediction of dynamic pressure distribution (\( P^{*} \)) is a subject of great importance in the design and operation of the hydraulic structures. Flip buckets, using as hydraulic structures for dissipation of the excess energy outflow, are usually constructed at the end of the chute of the spillways. In this research, based on experimental studie...

فناوری تیکه نگاری صوتی (Acoustic Tomography) یکی از جدیدترین و دقیق ترین فناوری های روز دنیا به منظور پایش پیوسته منابع آب در اقیانوسها، دریاها و رودخانه ها است که در حال حاضر در کشورهای توسع هیافته مورداستفاده قرار میگیرد. خروجی خام این سیستم به دلایل مختلفی حاوی داده های پرتی بوده که عدم شناسایی و حذف آنها موجب خطا در اندازه گیری میشود، لذا ضرورت...

Fluid–Structure Interaction (FSI) in pipes can significantly affect pressure fluctuations during water hammer event. In transmission pipelines, anchors with axial stops have an important role in the waterhammer-induced FSI as they can suppress or allow the propagation of additional stress waves in the pipe wall. More specifically, a reduction in th...

Pressure fluctuations are among the favorite topics for hydraulic engineers due to their critical role in the design and safe operation of hydraulic structures. In this study, three explicit data-driven models, including Classification and Regression Trees (CART), Gene Expression Programming (GEP), and Multivariate Adaptive Regression Splines (MARS...

Pile groups are employed in sea and ocean environments in order to support marine and offshore structures. Estimation of scour depth around pile groups is one of the important factors in the design of coastal and marine structures. The scour phenomenon is a serious hazard that threats the structural stability of piles. Data-driven methods are being...

Scour around piles is considered as one of the most important phenomena which could undermine the stability of piles. Data-driven methods are now being used more and more to predict complex phenomena such as scour around of pile groups. In this study, three data-driven methods including multivariate adaptive regression spline (MARS), classification...

Fluid–Structure Interaction (FSI) in pipes can significantly affect pressure fluctuations during water hammer event. In transmission pipelines, anchors with axial stops have an important role in the waterhammer-induced FSI as they can suppress or allow the propagation of additional stress waves in the pipe wall. More specifically, a reduction in th...

Fluid–Structure Interaction (FSI) in pipes can significantly affect pressure fluctuations during water hammer event. In transmission pipelines, anchors with axial stops have an important role in the waterhammer-induced FSI as they can suppress or allow the propagation of additional stress waves in the pipe wall. More specifically, a reduction in th...

This paper investigates the effect of fluid-structure interaction (FSI) on the efficiency of transient-based reflections analysis (TBRA) applied to the detection of extended deteriorations in a reservoir-pipe-valve system. A waterhammer-with-FSI solver, based on the method of characteristics (MOC) and the finite-element method (FEM), is used and va...

Fluid-Structure Interaction (FSI) in pipes can significantly affect pressure fluctuations during water hammer event. In transmission pipelines, anchors with axial stops have an important role in the waterhammer-induced FSI as they can suppress or allow the propagation of additional stress waves in the pipe wall. More specifically, a reduction in th...

In the present study, the effect of inlet flow condition of a stilling basin on the hydrodynamic parameters of flow as well as velocity and pressure distributions, vorticities, pressure fluctuations, turbulence intensities, and hydrodynamic loads were investigated. To do so, two practical and usual cases of flow at the downstream of a bottom outlet...

In the present paper, the effect of guide wall and pier geometry on the flow pattern of a dam spillway was studied. Different scenarios were numerically simulated to optimize the geometry of the guide walls and piers of the spillway in different hydraulic conditions. The RNG and VOF models were used for turbulence and free surface simulations, resp...

Transverse mixing coefficient (TMC) is one of the key factors in the modelling of lateral dispersion of pollutants. Several researchers have attempted to estimate this coefficient using various models. However, robust equations that can accurately estimate lateral mixing in both straight and meandering streams are still required. In this study, nov...

A least squares based meshfree method is used in the numerical simulation of a turbulent flow. The proposed approach is integral free, vectorized and enjoys sparse positive definite matrices. Here, the standard k–ε model is employed to model the turbulent flow. A matrix formulation is illustrated that simply can be extended for other turbulence mod...

There are various kinds of methods and techniques for water leakage detection from buried aqueducts. Most of them are costly and time consuming while Water companies need to identify leakage quicker than conventional approaches with lower cost and also cover larger areas. In the present study, the possibility of locating water leakages was evaluate...

Erosion and scouring caused by the outflow jets of hydraulic structures is one of the most important topics in hydraulic engineering. In free overfall spillways, a water jet impacts the erodible downstream bed almost vertically and creates a scour hole. The scour hole can affect the safety and stability of the dam. In the present paper, the multiva...

To dissipate energy and invert excessive discharge flow away from high dams into plunge pool, flip buckets are commonly designed and optimized by hydraulic model studies. In the present study, performance of chute flip buckets in different hydraulic and geometry conditions was investigated using experimental data of five different physical models....

A fully implicit least-squares-based meshfree method is used to solve the governing equations of viscoelastic fluid flow. Here, pressure is connected to the continuity equation by an artificial compressibility technique. A radial point interpolation method is used to construct the meshfree shape functions. The method is used to solve two benchmark...

In the present work, a numerical study was performed to analyze the flow behavior in a reservoir in the presence of strong vortices. A challenging subject in this study was the flow field in the reservoir and the mechanism of vortex formation. The numerical model was verified with the available theories and experimental data. Experiments were condu...

Thermal stratification is strongly associated with hydrodynamics, and plays an important role in the dynamics of water quality and the ecosystem of stratified water bodies. Changes in the climate or hydrological conditions can alter thermal regimes. This study aims to investigate the effects of climate change on the thermal structure of a reservoir...

The velocity field in a reservoir in the presence of surface vortices was experimentally studied. Experiments were performed with a horizontal intake and with a constant submerged depth and two different intake Froude numbers. The spline smoothing method was used to improve the graphical presentation of the measured data. Results are presented and...

This paper introduces the honey-bees mating programming (HBMP) algorithm as a novel tool for predicting suspended sediment concentration for the Mad River catchment near Arcata, USA. The paper also applies gene expression programming (GEP) as a comparison and shows that these two approaches can theproduce transparent, nonlinear relationships betwee...

A simple node enrichment strategy using a gradient based error estimator is presented for the Collocated Discrete Least Squares (CDLS) meshless method. Also, a procedure is defined to distribute collocation points according to the field nodes position. Here, shape functions are constructed using the Radial Point Interpolation Method (RPIM). As temp...

Wind waves are one of the important, fundamental and interesting subjects in port and coastal engineering. Thus, within years, different methods such as experimental methods, numerical modeling and soft computing methods have been employed to estimate the wave parameters. In this study, waves height in Anzali port is predicted using soft computing...

Abstract Background & Objectives: the past, collection and disposal of sewage in cities, was a serious problem and the necessity of the treatment in terms of public health and environmental issues associated was important. In this study Treatability of wastewater treatment in laundry unit by electrocoagulation process using two pair of aluminum and...

Spillways are constructed in the structure of a dam in order to drain the water excess to the reservoir capacity during the floods. Water outflow jet of spillways impacts the erodible downstream bed and causes the scour hole. Development of the scour hole may threaten the stability of the dam. Hence, downstream scour should carefully be estimated a...

Spillways are constructed in the structure of the dams in order to drain the water excess to the reservoir capacity. In the ski-jump bucket spillways, water jet impacts diagonally the downstream erodible bed and causes scour hole at the downstream of the dam. The scour hole development may threaten the stability of the dam. Hence, an accurate and c...

Least squares is a robust and simple method in function approximation. Collocated Discrete Least Squares (CDLS) is a meshless method based on least squares technique. In this paper CDLS is used with a non-incremental projection method for the solution of incompressible generalized Newtonian fluid flow equations in the simulation of laminar flow of...

Wave characteristics are necessary for many coastal operations and marine structures design. Different methods such as empirical methods, numerical models and soft computing have been developed for this purpose. In this study, one of the well-known numerical models, SWAN model, has been used for the prediction of wave parameters in Anzali, Caspian...

So far, many attempts have been made to identify the relation between discharge and suspended sediment load.Empirical relations such as sediment rating curves are often applied to determine the average relationship between discharge and suspended sediment load. This type of models generally underestimates or overestimateswhen sediment load are esti...

The Least squares approach is a robust and simple method for function approximation. Collocated Discrete Least Squares (CDLS) is a meshless method based on least squares technique enjoying symmetric and positive-definite properties. In this paper, the CDLS method is extended for the stream function-vorticity formulation of 2D incompressible Navier–...

Phosphorus is an important mineral element for organisms' growth. Nowadays, the use of detergents and cleaners has become one of the essentials of human life. Since these materials enter into the sewage systems, the existing polyphosphate reacts with water and gradually changes to phosphate ions and cause environmental problems. Electrocoagulation...

Free spans or suspended spans normally occur in subsea pipelines due to the irregularity of seabed and by scouring phenomena around the installed non-buried pipeline. The hydrodynamic around the pipeline can lead to a vibration of the pipeline.This kind of vibration may cause fatigue damage to the pipeline. In order to study the hydrodynamic around...

The scour below spillways can endanger the stability of the dams. Hence, determining the scour depth downstream of spillways is of vital importance. Recently, soft computing models and, in particular, artificial neural networks (ANNs) have been used for scour depth prediction. However, ANNs are not as comprehensible and easy to use as empirical for...

Free spans or suspended spans normally occur in subsea pipelines due to the irregularity of seabed and by scouring phenomena around the installed non-buried pipeline. The hydrodynamic around the pipeline can lead to a vibration of the pipeline.This kind of vibration may cause fatigue damage to the pipeline. In order to study the hydrodynamic around...

So far, various models have been developed to identify the relation between discharge and suspended sediment load. Empirical relations such as sediment rating curves are often applied to determine the average relationship between discharge and suspended sediment load. This type of model generally underestimate when sediment load are estimated from...

In this research, possibility of reducing excess sludge production in wastewater treatment was investigated using a combined anaerobic and aerobic submerged biological filter in a pilot scale. The physical model designed, erected and operated consisted of two pipes of PVC type with 147mm and 237mm diameter used as aerobic and anaerobic filters, res...

This study presents the development of classification and regression tree (CART), artificial neural network (ANN) and linear regression approaches to predict the critical submergence in an open channel flow for different clearance bottoms. To use the models for application purposes and cover the wide range of inputs, the nondimensional parameters a...

A novel approach to local radial point interpolation meshless (LRPIM) method is introduced to investigate the influence of leakage on tidal response in a coastal leaky confined aquifer system, based on a local weighted residual method with the Heaviside step function as the weighting function over a local sub-domain. The present approach is a truly...

Jabbari, E. and Talebi, O., 2011. Using Artificial Neural Networks for estimation of scour at the head of vertical wall breakwater. An accurate estimation of scour depth around a vertical wall breakwater is very difficult due to the complex behavior of the flow on an erodible bed in the estuarine and marine environment. In the current study, Artifi...

Saeedpanah, I., Jabbari, E. and Shayanfar, M A., 2011. A new approach for analyses of groundwater flow response to tidal fluctuation in a coastal leaky confined aquifer. Journal of Coastal Research, SI 64 (Proceedings of the 11th International Coastal Symposium), 1175 - 1178. Szczecin, Poland, ISSN 0749-0208 A new approach is introduced to analyze...

One of the most important factors in bridge destruction is scour around piers of bridges. The scour depth evaluation around the bridge pier is very critical in bridge design. Although there are several empirical formulas to predict depth scour, these formulas usually have not had accurate results. Therefore, there has been an increase in use of sof...

In this paper, the local radial point interpolation meshless method (LRPIM) is used for the analysis of two-dimensional potential flows, based on a local-weighted residual method with the Heaviside step function as the weighting function over a local subdomain. Trial functions are constructed using radial basis functions. The present method is a tr...

SAEEDPANAH, I. and JABBARI, E., 2009. A novel approach to local radial point interpolation meshless method (LRPIM) for numerical solution of groundwater flow response to tidal fluctuation in a coastal confined aquifer. In this paper the local radial point interpolation meshless method (LRPIM) is developed for the solution of groundwater flow respon...

Arvand River Estuary is the most important inland water body of Iran and its discharge has been reduced in the last decades due to construction of several dams. Hence, a two-dimensional laterally averaged time dependent hydrodynamic and water quality model called CE-QUAL-W2 was applied to this estuary to assess the impacts of river discharge reduct...

ABSTRACT: A genetic algorithm is used for the simultaneous layout and size optimization of pipe networks. A typical pipe network is a collection of pipes, reservoirs, pumps, and different kinds of valves connected to each other in order to meet specified demand at nodes. An engineering concept of reliability is used in which the number of independe...

Heuristic search techniques are highly flexible, though they represent computationally intensive optimization methods that may require thousands of evaluations of expensive objective functions. This paper integrates MODSIM, a generalized river basin network flow model, a particle swarm optimization (PSO) algorithm and artificial neural networks int...

SAEEDPANAH, I. and JABBARI, E., 2007. Simulation of water pollution in coastal areas using combination of the Meshless Local Petrov-Galerkin scheme with radial basis functions and the fuzzy parameters. Randomly-changing values in time and space of different parameters such as pollutant load sources and physico-chemical coefficients is the difficult...

JABBARI, E. and SAEEDPANAH, I., 2007 Simulation of sediment transport in coastal areas with Meshless Local Petrov-Galerkin scheme. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 943 - 948. Gold Coast, Australia, ISSN 0749.0208 The phenomenon of sediment transport plays an important role in the design of...

The aims of this study were to evaluate the SCOD removal efficiency in submerged biological aerated filters (BAFs) and subsequently to assess the relationship between the specific surface area (S_s) and Excess Sludge Production (ESP) rate in such filters. Accordingly, four filters with different porosity and specific surface (647, 295, 17...

The aims of this study were to evaluate the SCOD removal efficiency in submerged biological aerated filters (BAFs) and subsequently to assess the relationship between the specific surface area (Ss) and Excess Sludge Production (ESP) rate in such filters. Accordingly, four filters with different porosity and specific surface (647, 295, 175 and 136 m...

The determination of the longitudinal distribution of a substance in natural channels is based on the mass balance equation. In this equation the dispersion term accounts for the longitudinal mixing which results from the combined effects of turbulent diffusion and the shear-induced velocity distribution in both the transverse and vertical directio...

The main parameters that affect the salinity intrusion in estuaries are their geometric, hydrologic and hydrodynamic characteristics. The recognition of effective parameters and understanding their roles in the salinity intrusion are required for estuarine water management. In this study, the governing equations of the salinity intrusion processes...

Numerous models have already been worked out to achieve an optimum design of a pressurized water conveyance system. These models have mostly been made for the analysis and the design of a water distribution network in which layout of the system is more or less fixed. In the design of a water supply line, however, layout of the line could also be op...