Mohammad Vaghefi

Mohammad Vaghefi
Persian Gulf University | PGU · Department of Civil Engineering

Associate Professor of Hydraulic Structures

About

130
Publications
28,103
Reads
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1,334
Citations
Citations since 2017
46 Research Items
1017 Citations
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
Additional affiliations
April 2012 - September 2017
Persian Gulf University
Position
  • Professor (Associate)
February 1999 - present
Persian Gulf University
Position
  • Professor (Assistant)
February 1999 - present
Persian Gulf University
Position
  • Research Assistant
Description
  • Hydraulic, Hydrology, Dam Engineering, Fluid Mechanics, River Engineering, Advanced Hydraulics, Sediment Hydraulics, Hydrodynamic, etc.
Education
September 2005 - March 2009
Tarbiat Modares University
Field of study
  • Hydraulic Structures
September 1997 - September 1999
Shiraz University
Field of study
  • Hydraulic Structures
September 1992 - September 1996
Shiraz University
Field of study
  • Civil Engineering

Publications

Publications (130)
Article
This paper presents a computationally efficient and an accurate methodology called the incremental differential quadrature method (IDQM) for analysis of the nonlinear two-dimensional Burger’s equation. This equation is used to model the phenomenon of the fall of sediment particles in its dimensionless form. Both the spatial and the temporal domains...
Article
Full-text available
In this paper, the effect of collar width ratio on the flow pattern around an oblong pier in a 180-degree channel bend was experimentally studied. This channel has a rectangular cross section. It is 1 m in width and 0.7 m in height. The upstream and downstream paths are respectively 6.5 and 5 m long. The ratio of the bend's central curvature radius...
Article
This paper investigates the transient behavior and the water hammer in pipelines due to rapid changes in the operation of the group of parallel pumps. After a brief introduction of the water hammer and the boundary conditions related to the transient characteristics of a group of pumps with a parallel arrangement, a time marching second-order finit...
Article
Full-text available
– Due to serious damage of concrete structures caused by natural hazards and accidents, evaluating dynamic response of these structures is one of the most important objectives in the field of engineering. In this article, a case study is carried out in order to understand influences of blast load on a concrete bridge. In order to do so, 3D Finite E...
Article
Full-text available
As 180-degree meanders are observed in abundance in nature, a meandering channel with two consecutive 180-degree bends was designed and constructed to investigate bed topography variations. These two 180-degree mild bends are located between two upstream and downstream straight paths. In this study, different mean velocity-to-critical velocity rati...
Article
Full-text available
An open channel flume with a central 180-degree bend with a rigid bed is designed to obtain a better understanding of the complex flow pattern around a T-shaped spur dike located in a sharp bend. The 3-dimensional velocities are measured by using an acoustic Doppler velocimetry under clear-water conditions. This study’s primary objective is to comp...
Preprint
Full-text available
As 180-degree meanders are observed in abundance in nature, a meandering channel with two consecutive 180-degree bends was designed and constructed to investigate bed topography variations. These two 180-degree mild bends are located between two upstream and downstream straight paths. In this study, different mean velocity to critical velocity rati...
Article
In this paper, the scouring around a triad series of vertical bridge piers located in a bend is investigated using SSIIM software. To this end, some of the most essential parameters such as the relative radius and the bridge pier position in both transverse and longitudinal directions to the flow have been examined. Then the bed topography variatio...
Article
Various protective methods are incorporated in order to change the flow pattern and reduce the intensity of the vortices around the piers with the aim of reducing scour at bridge piers. One of these methods is the employment of submerged vanes at the upstream side of the bridge piers. This study investigated the effect of the submergence ratio of t...
Article
In this study, effects of inclined pair piers on bed topography in a scaled river bend were experimentally investigated. Three separate groups of experiments under clear water, incipient motion and movable bed conditions were performed. The results showed that for a pair of V-shaped piers, the scouring was higher for the pier closer to the bend out...
Article
In the present study, the effect of peak occurrence time and flood duration on the scour around the bridge pier installed in a sharply bended channel was investigated. For this purpose, several simple single-peaked hydrographs with the same durations and different peak occurrence times were produced in laboratory. In addition, hydrographs having tw...
Article
Full-text available
As the concrete material is eliminated from the locations situated around the middle of the cross-sections of bubble decks (BDs), chiefly at mid-span, the DB type slabs are lighter than the solid slabs. That is why the use of the BD slabs has been augmented recently. In the building codes of practice, the response modification factor (RMF) is gener...
Article
Numerous bridges are destroyed worldwide every year mostly due to the role of hydraulic factors including scour being ignored when they are designed. Therefore, examination of the scour phenomenon around bridge piers in rivers and identification of the parameters affecting them gain a great level of significance. Particularly, if the bridge piers a...
Article
Full-text available
This work has compared the performance of three well-known artificial neural network (ANN) approaches in turbulent flow pattern modeling based on geometric characteristics of the channel (angle of horizon, distance from outer bank of the bend, and distance from the bed) in a 180° sharp bend with and without a T-shaped spur dike. ANN methods discuss...
Article
With the advancement in the science of engineering, bridge piers scouring has become a well-known phenomenon, and engineers have always been making efforts to counter such a destructive phenomenon. One of the methods used to reduce scouring around the bridge pier is application of other hydraulic structures which influence the amount of scouring in...
Article
In this paper, in order to investigate the effects of abutments in presence of a pier on scour depth and bed topography alteration, a series of tests were carried out considering abutments with a length twice that of the pier and vertical and inclined piers with their inclination towards upstream, downstream, inner and outer banks. The results show...
Article
This paper focuses on developing a numerical model based on Implicit Local Multiquadric Based Differential Quadrature Method for simulation of water hammer phenomena in a pipeline system consisting of a valve, pipe and surge tank. This model is used with the aim of reducing computational costs and increasing accuracy. After brief interdicting of go...
Article
Various factors such as human or instrument errors, measurement conditions, and the nature of the flow under unique circumstances may lead to the generation of data inconsistent with the normal pattern of the statistical population and result in the assumption that they may have been generated through a different process. In a general definition, t...
Article
Full-text available
A mesh-free numerical model based on the Radial Basis Function Differential Quadrature is introduced to simulate the hydrodynamic response of the dam-reservoir-foundation system affected by earthquake acceleration. The governing equation of the hydrodynamic pressure of dam-reservoir system with non-vertical face shape was discretized using the pres...
Article
Full-text available
This paper is aimed to investigate the temporal variation of scour depths and bed topography in the presence of a group of six vertical and inclined piers placed in a 180-degree bend flume. For this purpose, a series of tests were performed in a test flume provided by Hydraulics Laboratory of Persian Gulf University, Bushehr, Iran. The piers were p...
Article
Data collection related to the flow pattern has always been associated with outliers due to various reasons. Outlier detection in flow pattern experiments is of high importance and results in a better and more accurate understanding of the flow pattern. In this study, six data mining methods have been used to identify the outliers in flow pattern e...
Article
This piece of research presents flow pattern around a T-shaped spur dike in repelling, attractive, and vertical positions in a 90° mild. To this aim, SSIIM CFD software, one of the most powerful software applications in hydraulic engineering field, was employed. In this research, Navier–Stokes equations and k–ε turbulent model were used for solving...
Article
Every year, thousands of bridges around the world are destroyed by scouring around their piers. One of the methods to control and protect the piers against scouring is to use submerged vanes. The purpose of this paper is to investigate the effect of upstream submerged vanes on scouring around the bridge pier and bed topography changes. For doing ex...
Conference Paper
به دست آوردن جواب تحلیلی برخی از معادلات دیفرانسیل جزئی غیرخطی، مگر در شرایط خاص امکان‌پذیر نمی‌باشد که این‌گونه معادلات را می‌توان با روش‌های عددی حل نمود. معادله‌ مورد نظر در این تحقیق، معادله برگر در حالت دو بعدی وابسته به زمان است که پدیده سرعت سقوط ذره درون سیال نزدیک به سکون مانند آب رسوب دار پشت یک سد را مدل می‌کند. در این تحقیق برای حل معاد...
Article
Full-text available
Accurate outlier detection is an important matter to consider prior to data applied to predict flow pattern. Identifying these outliers and reducing their impact in measurements could be effective in presenting the authentic flow pattern. This paper aims to detect outliers in flow pattern experiments along a 180 degree sharp bend channel with and w...
Article
Full-text available
Since in bubble deck (BD) system, the concrete in the middle of deck’s cross sections, mainly in the middle of the spans, is removed, the slabs become lighter compared to the traditional slabs. The application of this type of structural system has been recently increased. In the researches, the ductility factor is expressed generally for the reinfo...
Article
In this study, scouring around piers perpendicular to flow (PPF) and piers toward the flow (PTF) under clear-water condition was examined by placing a set of triad cylindrical piers with a 5-cm diameter and a 15-cm center to center distance at the positions of 60, 90, and 120° of the bend at a constant flow rate of 70 l per second. Natural sand of...
Article
Full-text available
In the present research, by using a numerical model, some analyses were performed on flows around a T-shape spur dike and a support structure located at its upstream under different wing to length ratios of T-shape spur dike in the order of 0.25, 0.50, 0.75 and 1.00. In order to verify numerical model, physical model data were used in presence of a...
Article
This piece of research simulated the flow pattern around a T-shaped spur dike in the vicinity of attractive and repelling protective structures in a 90° bend using computational fluid dynamic (CFD) model. This CFD analysis has utilized RNG turbulence model to simulate turbulent flow field, and free surface variations were modeled through finite vol...
Article
This study investigates the lateral buckling of pipelines on a rigid seabed under temperature and internal pressure, regardless of the effects of waves and currents. The analytical results in some cases are compared with the numerical results obtained from ABAQUS software. Then, the inuence of effective parameters (such as internal pressure, fricti...
Article
Full-text available
The local buckling has always been known as an undesirable and destructive phenomenon in steel structures. Thus, it is necessary to identify the effective factors in local buckling of the steel box column. Currently, box columns are generally fabricated by welding plates using fillet or groove welds with various manufacturing patterns,in terms of w...
Article
Base-level fall in river beds occurs due to varying natural or unnatural causes. Base-level fall causes the change in the behavior of flow at the location of drop in base-level. In such situations, most of scour occur at the foot of the slope, and slope wall retreats in the upstream direction. This phenomenon widens the wall of the river bank, thus...
Article
One of the most important concerns of hydraulics engineers is predicting erosion at the outer banks of rivers by studying the flow pattern along the bend. Not only are the streamlines in meanders non parallel curved lines, but they are also twisted. To study the streamlines flowing a sharp bend, a 180° sharp bend was constructed at Persian Gulf Uni...
Article
Full-text available
The capacity of reinforced concrete sections highly depends on the interaction between reinforcing bars and surrounding concrete. The buckling of longitudinal steel bars have an important role in the nonlinear behavior of RC sections. In order to nonlinear analyzing of the bar's buckling in RC columns, two types of column and joint elements are mod...
Article
Full-text available
Spur dikes are used widely as flow control structures in rivers. The main direction of the flow is changed by a spur dike, which is accompanied by formation of separation and reattachment zones around the spur dike. This study was focused on the effect of a submerged single T-shaped spur dike and the influence of the distance between non-submerged...
Article
One of the methods to strengthen the structures against the seismic lateral loading is the employment of the composite columns. A concrete-filled tube (CFT) has the cumulative advantages of steel and concrete. Concrete-filled steel tube columns have been widely used in the moment-resisting frame (MRF) structures, located in both non-seismic zones a...
Article
Full-text available
In this paper, the scour hole dimensions around submerged and emerged spur dike in a 90° bend along with the mean and turbulent flowfield were investigated experimentally. Two types of re-circulating flow at the downstream of the spur dike and around the spur dike wing were observed. A direct relation between the estimated bed shear stress using TK...
Article
The flow field around a T-shaped spur dike located in a 90° bend is investigated experimentally. The three-dimensional Acoustic Doppler Velocimeter (ADV) was used for measuring the flow field. The comparison of the three dimensional components of velocity was made in different sections of the bend and the differences of the flow pattern along the b...
Article
Bridge piers are highly susceptible and sensitive to scouring effects, so careful determination of scour depth can ultimately lead to more properly designed pier foundation. The goal of this study is to evaluate scour depth and location around an inclined cylindrical bridge pier in the apex of a sharp 180-degree bend, and also to compare the result...
Article
Spur dikes are used for river training purposes. To meet the navigability of rivers, the mean annual flow is considered; hence, in terms of river flooding, spur dikes are necessarily submerged. Considering the importance of submerged spur dikes, this paper studied the effects of a T-shaped spur dike's submergence ratios on turbulent flow parameters...
Article
Spur dike is one of the river training structures. This work presented a numerical simulation of flow field and three-dimensional velocity around a T-shaped spur dike located in bend using SSIIM model. The main objective of this work is to investigate the three-dimensional velocities and streamlines at transverse and longitudinal sections and plan...
Article
الگوي غالب رودخانهها در پلان بصورت پیچانرودي میباشد. با استقرار پایههاي پل در رودخانه یک سلسله جریانهاي گردابی ایجاد میشود. این گردابهها عامل اصلی آبشستگی به حساب میآیند که در دراز مدت باعث ایجاد چاله آبشستگی در محل پایه پل می شوند. آبشستگی موضعی عامل اصلی خرابی پل ها در سراسر جهان میباشد. از آنجا که رودخانههاي پیچانرود متداولترین نوع رودخانهها در...
Article
High flow velocity near the free surface in rivers is due to the presence of shear stress near the bed and its absence on the free surface. This phenomenon results in unsteadiness of the vertical velocity profile. Moreover, secondary flows in river bends cause velocity variations, accordingly leading to changes in shear stress near the bed. The pre...
Article
Full-text available
In this paper, a new approach for nonlinear numerical modelling of the reinforced concrete shear walls with consideration of bar-concrete interaction and shear deformation is proposed. Bar and concrete stress-strain relations, the bar-concrete interaction, the shear stress-strain relation and, also, their cyclic behavior including the strength degr...
Article
Spur dikes are hydraulic structures frequently applied to protect rivers’ banks. Since flow pattern around a spur dike located in a rivers’ bend is particularly complicated due to the existence of secondary flow and helical flow, the effect of submergence ratio on flow patterns around a short T-head spur dike located in a 90° bend has been monitore...
Article
The influences of thermal environment on the free vibration characteristics of functionally graded (FG) truncated conical panels are investigated based on the first-order shear deformation theory (FSDT). By taking into account both the temperature dependence of material properties, which are assumed to be graded in the thickness direction, and the...
Article
Currently, box columns are fabricated by welding plates using fillet or groove welds. According to probable seismic failure mechanism of these columns, their nonlinear behavior in terms of ductility and strength is necessary. In this research, a variety of columns with different welding patterns including groove and fillet welding with various over...
Article
Full-text available
In this paper, the bed topography of a channel at a 90-degree bend was studied at the T-shaped spur dike installed at the middle of the outer bank. Numerical analyses were performed with the Sediment Simulation in Intakes with Multiblock Option (SSIIM) model. Three relative curvatures (R/B = 2, 3, and 4) related to the three sediment densities (P =...
Article
Full-text available
The analysis of the dynamic response of a circular tunnel in three types of soil at different depths under surface detonation of a 250-kg TNT charge reveals that the tunnel peak particle velocity and the failure zone length are sensitive to the soil type and material properties. The buried tunnel in silty clay sand has the least damage; the length...
Article
This article studied the effect of submergence percentage of the T-shaped spur dike on scour and flow pattern in a 90° bend. Three submergence percentages of 0, 15 and 25 were considered. The three-dimensional flow velocities were invoked using SSIIM software. The distance between maximum scour hole depth and spur dike situation was fixed by changi...
Article
This study investigates in to the dynamic response of an inclined cross-ply laminated composite beam traversed by a moving mass. For this purpose, a finite element method based on the classical lamination theory is used. By taking the effects of inertial, Coriolis and centrifugal forces, the property matrices of the moving mass element are extracte...
Article
Reduced beam section (RBS) moment resisting connections are among the most economical and practical rigid steel connections developed in the aftermath of the 1994 Northridge and the 1995 Kobe earthquakes. Although the performance of RBS connection has been widely studied, this connection has not been subject to in the skewed conditions. In this stu...
Article
Full-text available
A fundamental principle in the safe design of bridge piers is to estimate maximum scour depth. As such, many researchers devoted their efforts to study the phenomenon of scour around bridge piers and to present relationships to estimate maximum scour depth. In the current research, scour around circular bridge piers with two different diameters and...
Conference Paper
In this research, a bend channel with a 180 degree central angle (curvature radius to channel width equal to 2) was designed and built in the hydraulic laboratory of Persian Gulf University in order to help better understand complicated flow pattern in a sharp bend. Vectrino velocimeter was employed to measure velocity components and determine bed...
Article
Full-text available
Today, concrete is the most widely used construction material in the world, cement is major component of concrete. Consuming energy in cement industry is very high and CO2 emissions generated during the production of Portland cement has serious environmental threatens. Therefore utilize of pozzolanic material as a supplementary cementitious materia...
Article
Full-text available
In this paper, flow and scour patterns resulted from the installation of two T-shaped spur dikes were evaluated in a 90° bend under clear water conditions. The submerged and non-submerged spur dikes were modeled at different locations in the bend using the numerical model. Based on the dikes’ location and submergence, different scour holes on the c...
Article
Full-text available
The purpose of this paper was to study the local scour formation due to an inclined circular bridge pier. The experiments for two cases of inclined and vertical piers under clear-water condition with four different flow conditions have been performed. The experiments were conducted in the hydraulic laboratory of Tarbiat Modares University in a rect...
Article
Bracings, due to their high rigidity and strength, are widely employed in seismic design of steel buildings. They play a fundamental role in the absorption and dissipation of earthquake forces. Failures of braced steel buildings are often clue to the shortage of compressive strength and out-of-plane buckling of bracing connections. One of the facto...
Research
Full-text available
Flow pattern in river bends is very complicated and fully three dimensional in nature with high turbulence intensity. This flow has a great influence on the river morphology by eroding the outer bank which results in deposits of sediment at the inner bank. Owing to the importance of the study of such flow, in this study flow in bend was simulated u...
Article
Spur dikes have been usually applied as river-training structures for many years. One of the spur dikes with the proper application in the regulation of rivers is a T-shaped spur dike. In this paper, we study the effects of relative curvature of bend on scour pattern due to installation of a T-shaped spur dike with equal ratio of wing to web length...
Conference Paper
The Reynolds shear stress and Turbulent Kinetic Energy are two of the important parameters when predicting the turbulent flow pattern in river bends, because such parameters indicate flow structures, especially the secondary flows. Since the product of the velocity components' fluctuations in various directions can be used to show the Reynolds shea...
Article
The nonlinear behavior of reinforced concrete columns subject to biaxial bending and consideration of bond-slip at the steel-concrete interface are investigated. Separate degrees of freedom are used for the steel and concrete parts to allow for the difference in displacement between the reinforcing bars and the surrounding concrete. The effect of b...
Article
Full-text available
Totally, spur dike is an economical way to preserve morphology of rivers. Numerical methods can be useful for evaluating hydraulic parameters for spur dike because of their reduced simulation time, while experimental ones take a long time and need lots of tools to simulate any models. In this paper, flow patterns around a T-shape spur dike and a su...
Article
Keywords Abstract Three-dimensional Velocity 180 Degree Sharp Bend Flow Pattern Vectrino Velocimeter River bend routes are one of the considerable areas in flow pattern investigation. The flow in river bends is affected by centrifugal force and pressure gradient. Thus, studying 3D flow pattern in bend routes is of high importance. The aim of this p...
Article
Because of the great importance of shear stress parameter in river sediment transport mechanisms, different methods for calculating them are presented. This paper has used Depth-Averaged Method to study and analyse shear stress distribution near the bed in a 180 degree sharp bend. The results suggested that the maximum dimensionless shear stress ne...
Article
In this paper, flow pattern around an unsubmerged T-shaped spur dike in a 45 degree position, and located in a 90 degree bend with different Froude Numbers has been studied using Flow-3D and has been compared with experimental results. To determine the effect of Froude Number on flow pattern, flow pattern in longitudinal, cross, and plan sections h...
Article
Spur dike is one of the hydraulic structures used in rivers to protect river banks. In this paper, flow pattern around a T-shaped spur dike which is located in a 90 • bend and different amounts of submersion has been studied using Flow-3D. Numerical results have been compared with experimental results and have been analysed.
Article
Full-text available
Today’s with increasing of capacity of the ports and ships dimension, the needs for applying an appropriate berthing (fenders) system has been also increased. The principal function of the fender system is to prevent the vessel or the dock from being damaged during the mooring process or during the berthing periods. Forces during the vessel berthin...
Article
This paper examines the effect of geometric parameter of wing to web length ratios of T-shaped spur dike in a 90 degree bend on scour around them using SSIIM software. The results show that the main scour hole to about two-thirds, or 67 percent of channel width has developed towards the outer wall. Analysis of scour pattern result, Cavity geometry...