Masoud Ghodsian

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Verified

Masoud verified their affiliation via an institutional email.

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• PhD
• Professor at Tarbiat Modares University

This research investigates scour dynamics downstream of triangular piano key weirs (PKWs), which can cause significant channel bed erosion. The study analyzed scour effects under four discharge conditions and varying submergence ratios in fine gravel and medium gravel beds within a 10 m long, 0.75 m wide, and 0.80 m high channel. Findings reveal th...

With advancements in monitoring natural processes on Earth, remote sensing has become an efficient tool for analyzing both variables such as precipitation, soil moisture, vegetation cover, land use and events similar to floods, land slide, erosion and sedimentation. The integration of remote sensing technologies has revolutionized water resource ma...

Investigating the downstream bed configuration of culverts is vital for assessing the integrity and performance of hydraulic structures. This study examined the bed topography downstream of a box culvert with a fixed bottom through a series of controlled experiments, investigating the effects of wing-wall angles, particle Froude numbers, and relati...

This study investigates the effectiveness of flow splitters in reducing scour downstream of trapezoidal Piano Key Weirs through a comprehensive experimental study. Three distinct geometries of flow splitters—square, rectangular, and circular—are examined under various hydraulic conditions to assess their impact on local scouring. The experiments we...

Analysis of bridge failures due to scouring has been extensively studied by different researchers in recent years and as a result various methods of controlling local scour cavity have been given. Since most of the research in this field has been done on straight paths and also the complexity of the flow pattern in bends, studying the scouring patt...

Understanding the downstream bed topography of culverts is essential for assessing the stability and performance of hydraulic structures. This study evaluates the downstream bed topography of a box culvert through a series of controlled experimental tests, considering variables such as wing-wall angles, particle Froude numbers, and relative tailwat...

The assessment of scour depth downstream of weirs holds paramount importance in ensuring the structural stability of these hydraulic structures. This study presents groundbreaking experimental investigations highlighting the innovative use of baffles to enhance energy dissipation and mitigate scour in the downstream beds of rectangular piano key we...

Soil fluidisation around buried pipes is one of the water leakage effects that has a direct influence on the ultimate failure of pipelines. In this research, using a laboratory model, the fluidisation caused by water leakage from three cracks with three lengths (14, 17, and 20 mm) and a 3 mm diameter hole for five pressures (1.5–5.5 bar) in non-uni...

This research investigated the local scour downstream of Piano key weirs (PKWs) with various shapes in plan, including rectangular, trapezoidal, and triangular. The experiments were conducted under various flow conditions with two different bed material sizes. The findings revealed that the scour parameters downstream of the PKW models followed sim...

In this paper, the scour downstream of a trapezoidal Piano key weir (PKW) is investigated under free and submerged flow conditions. For this purpose, an experimental model was used in a laboratory channel with a length of 10 m, width of 0.75 m, and height of 0.8 m at various discharges and tailwater depths. The results showed an increase and decrea...

This paper investigated the efficiency of the traditional weir equation (TWE), Domínguez, adjusted Domínguez, and Schmidt approaches, as an alternative to the De Marchi procedure, for computing discharge of a sharp-crested triangular side weir. Comprehensive experimental data were used for the analysis, including 342 data from the present study and...

In this research, the flow and scour patterns downstream of type-A rectangular piano key weirs (PKWs) were studied experimentally and numerically. Variations of the bed topography downstream of the PKW with different lateral crest shapes, i.e., a standard crest and a crest with an indentation in various geometries, including triangular, half-circul...

Employment of protective structures is vital for reducing the effect of the local scour created surrounding the bridge piers. One of the most effective protective structures used for controlling and reducing scour surrounding the bridge piers is the collars. Hence, research on the mechanism of scouring surrounding the combination of pier and collar...

In this paper, results of experiments on the discharge coefficient of rectangular Piano key weirs are presented. Experiments were conducted in a recirculating flume with 10 m length, 0.75 m width, and 0.9 m height. The walls and bed of the flume were made of glass and metal, respectively, and supported by metal frames. Experiments were conducted us...

Introduction: Piano Key Weir (PKW) is the newest type of nonlinear Labyrinth Weirs (LWs). An initial study on this weir has indicated that it can significantly increase the discharge besides having a simple and economical structure. During the past years, different researches have been done to check the factors effecting the flow discharge and opti...

Introduction: Piano key weir (PKW) is a type of long crest weir, with more crest length in the same width, and the capacity of weir is higher than that of a linear weir. The piano key weirs are used in the crest of reservoir dams and in irrigation and drainage networks. So far, many studies have been done on the discharge coefficient of the piano k...

One of the major problems of weirs located on an erodible bed is downstream scouring, which can endanger their stabilities. In this study, downstream scouring of a type-A trapezoidal piano key weir (PKW) was experimentally investigated. The experiments were carried out in a channel with a length of 10 m, a width of 0.75 m, and a height of 0.8 m. Th...

This study experimentally investigated the temporal evolution of the scour parameters downstream of a trapezoidal piano key weir. The densimetric Froude number (Frd50) in the range of 0.39–0.57 and the relative vertical distance of the sediment bed level to the weir toe (Δz/P) in the range of 0.025–0.5 were taken into consideration. In general, wit...

In this research, the flow and scour patterns downstream of a rectangular Piano Key Weir (PKW) were studied experimentally and simulated by using the Flow-3D numerical model and with RNG turbulence model. It was found that the Flow-3D model simulates the scour downstream of a PKW with acceptable accuracy. Variations of the bed topographical downstr...

In this paper, a fluidized granular sand bed by a vertically upward water leak jet was studied experimentally. It was found that an increase in the size of sand particles decreases the height of the fluidized zone, and vice versa. By increasing the cover depth, the height and area of the fluidized and mobilized bed zones are reduced. Dimensions of...

Estimation of maximum possible scour depth around spur dike is an important step in the design of spur dike foundations To determine the maximum scour depth in the design of spur dike foundations, the equilibrium scour depth, which is commonly estimated using peak-flow conditions for engineering design of spur dike foundations, are used. In fluvial...

The climatic change has led to the sea-level rise (SLR), which is expected to continue based on the current industrial and human activities. Previous studies indicated that most of estuaries which are of great environmental and economic importance are likely to be affected by SLR. Thus, understanding the hydrodynamic behavior of estuaries under SLR...

Laboratory experiments were carried out to study the behavior of turbidity current under subcritical approach flow condition. In order to study the effects of solid obstacle and bed roughness on turbidity current, 24 experiments were conducted. Two trapezoidal macro-roughness elements with 0.01 m and 0.03 m height and three triangular obstacles wit...

One of the problems with the piano key weir and the flow through the spillway in general is the oscillation of the water blade after spillway. The use of nappe breaker is one of the effective methods to reduce the oscillation phenomenon. Therefore, in this research, by placing the nappe breaker on the outlet of the weir, the effect of these nappe b...

In this paper, a straightforward approach was applied for estimating the discharge of sharp-crested rectangular and triangular side weirs. The extensive experimental data (356 for rectangular side weir and 362 for triangular side weir) and the available data from other sources (171 for rectangular side weir and 145 for triangular side weir) were us...

This paper focuses on Piano Key Weirs (PKWs) as an effective solution for improving the discharge capacity of spillway systems. The flow behavior in inlet and outlet keys is experimentally studied to analyze the discharge capacity of PKWs with different plan shapes (i.e., rectangular, trapezoidal, and triangular). The results show that in outlet ke...

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...

One of the causes of the destruction or damage of many bridges in the world is the local scour around the bridge piers. Accordingly, research on effective factors on the scouring pattern around the bridge piers is a necessity. In this study, the parameters of the scour hole created around rectangular piers, such as the depth, area and volume of the...

In this paper, the effects of the nondimensional parameters influencing the discharge coefficient of a side-combined structure located in a channel bend were studied using 288 experimental data. Experiments were conducted in a rectangular recirculating U-shaped channel (0.6 m width and 0.7 m height) for different discharges and depths of flow in th...

The leakage in the urban water distribution networks wastes a large amount of treated water, every year. Therefore, investigation of this phenomenon is necessary. In this research, the leakage discharge from a 2.5-mm diameter hole located in the beneath of a polyethylene pipe is investigated in three types of sandy soils. The soils employed in the...

Scouring around the bridge's piers is one of the major causes of serious damage to the bridge pier. A laboratory modelling method has been utilized in this research to study the effect of level and thickness of collar on scouring around the pier. The experiments were carried out in a channel with a 180° bend and a relative curvature radius equal to...

Piers and abutments cause local contraction in the rivers. As a result of the contraction, the water level increases in the upstream section of the bridge named as afflux. Afflux is one of the key concerns in the design of a bridge construction and the afflux estimation is important since the specific regions in the upstream of the bridge must be p...

Introduction The newest type of nonlinear weir is Piano key weir. Initial studies on this weir have shown that this weir significantly increases the discharge, has a relatively simple structure, and is an economic structure. Various studies have been conducted to investigate the factors affecting the discharge and optimization of this type of wei...

جديدترین نوع از سرريزهاي غیرخطی سرريزهاي کلید‌پیانویی هستند. مطالعات اوليه بر روي این سرریز نشان داد که این سرریز دبی را به ميزان قابل توجهي افزايش مي‌دهد، ساختاري به نسبت ساده دارد و سازه¬ای اقتصادي است. در طی سالیان گذشته پژوهش¬های مختلفی برای بررسی عوامل موثر بر آبگذری و بهینه¬سازی این نوع سرریز انجام شده است. اما مقایسه ای کامل در خصوص جریان و...

جديدترین نوع از سرريزهاي غیرخطی سرريزهاي کلید‌پیانویی هستند. مطالعات اوليه بر روي این سرریز نشان داد که این سرریز دبی را به ميزان قابل توجهي افزايش مي‌دهد، ساختاری به نسبت ساده دارد و در هر شرايطي به سهولت قابل اجرا و سازه¬ای اقتصادي است. در طی سالیان گذشته پژوهش¬های مختلفی برای بررسی عوامل موثر بر آبگذری و بهینه¬سازی این نوع سرریز انجام شده است. ا...

In this paper, the effect of increase collar thickness has been investigated by considering other parameters affecting the flow pattern around the oblong bridge pier located at 90˚ from the 180˚ bend constant. Data acquisition was performed using the Vectrino 3D velocimeter. The leveling of the collar in both tests is constant and 0.4 times the pie...

A series of experimental observations are presented in the current study to discuss the effects of artificial bed roughness on the turbidity current flowing in a rectangular channel with an abrupt change in bed slope. For this purpose, two different types of elements, sinusoidal and trapezoidal, with various heights and arrangements are considered...

Labyrinth weir is one of the approaches to increase the discharge capacity. An arced ‎configuration improves the orientation of the labyrinth weir cycles to the approach flow and ‎increases the weir crest length for a given width. In this study, the effects of the entrance flow ‎conditions on the hydraulic‏ ‏performance of the arced ‎labyrinth weir...

The piano key weirs have been considered by designers as a sure solution to increase drainage capacity. This study investigates the effect of the weir location of the internal and end state of the channel under free and submerged flow conditions. After the laboratory examination, the state of the interior showed a higher discharge coefficient than...

Increasing human activities, such as urbanization, and the construction of hydraulic structures along with climate change, have caused changes in the flow of rivers. On the other hand, coastal areas, estuaries, and rivers have been confronted with increasing Pollutants and nutrients. Therefore, it is very important to check the presence time of pol...

Today, there is a growing concern about the pollutants and nutrients in coastal areas, estuaries, and their tributary. The retention and export of these materials inside a system depend on the residence time. Considering the economic and environmental significance of the New York estuary and the Hudson River, as well as the entry of urban and agric...

Burrowing-type suction pipe method is a siphon dredging technique which removes sediment. This innovative technique attracted the attention of many researchers, recently, because of main advantages such as preventing water loss and conserving downstream environmental sustainability of dams. This study investigates the influence of geometrical and m...

One of the main causes of damage to dams, especially earth dams is the overtopping which may cause huge human losses and financial damages. Fuse plug is used as a safety valve to protect dams against catastrophic damages of overtopping. The increasing outbreak of floods and their huge and sometimes irrecoverable damages has incentivized dam experts...

The management of flood entering the reservoir of the dam and flood control to prevent the overtopping of the dam and dam destruction, especially in the embankment dams, is something that designers are particularly concerned about. The embankment fuse plug is used as a safety valve to protect the dam against catastrophic dam break caused by overtop...

The effects of an obstacle on the suspended load transport rate of supercritical turbidity currents were investigated experimentally. A Vectrino velocity meter was used to measure velocity and sediment concentration profiles. The effects of important parameters including inlet discharge, mean inlet sediment concentration and obstacle height on susp...

In this paper, effects of bed roughness on the flow pattern and turbulence characteristics, such as velocity contours, shear stresses, Reynolds stresses and turbulence intensities on a three-dimensional wall jet were investigated experimentally. The experiments have been conducted in a channel which is made of metal floor and glass walls, width 0.5...

Overtopping is the most probable reason for the dam breaking phenomena, particularly for embankment dams, that could pose danger to many human lives and properties. The fuse plug is used as a safety valve to protect the dam from catastrophic failurs caused by overtopping flow. In this experimental study, using a series of experimental tests, the ef...

For a given width, labyrinth weirs provide an increase in the weir crest length, which increases the weir flow capacity. Labyrinth weirs are generally designed in linear configurations. However, arced configurations have been employed in reservoir applications to improve the orientation of the weir cycles to the approach flow and to further increas...

This paper experimentally studies the hydraulic characteristics of arced weirs located in a reservoir. The accuracy and ability of the response surface methodology (RSM), especially central composite design (CCD), to describe the hydraulic performance of this type of weir is validated using experimental data. The discharge coefficient of arced weir...

This paper experimentally studies the hydraulic characteristics of arced weirs located in a reservoir. The accuracy and ability of the response surface methodology (RSM), especially central composite design (CCD), to describe the hydraulic performance of this type of weir is validated using experimental data. The discharge coefficient of arced weir...

Floods, with huge amount of water and sediment, play an important role in deposition and distribution of sediment in reservoirs. In this paper, the flow pattern and characteristics of delta in a reservoir are experimentally studied using steady and unsteady flows of water and sediment. The experiments were carried out using triangular and trapezoid...

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In this paper, scour and flow fields around two spur dikes with different submergence ratios located in a 90 developed bend were experimentally investigated. The spur dike and scour rate around the low submerged spur dike are higher than those around the high submerged condition. The ejection and sweep events are the predominant events in the upstr...

Turbidity currents are one of the most important factors in sedimentation process in dam reservoirs. Increasing the sediment deposition in front of a dam declines its storage capacity and poses significant operational challenges. Therefore, understanding of turbidity currents fluid dynamics and associated depositional patterns is crucial for effici...

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...

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...

The Swash zone, as extreme area of inner surf zone, influences coastal area and coastal structures. It defined as the part of the beach between the minimum wave run-down and maximum wave run-up. It constitutes a beach area where waves dissipate or reflect their remaining energy after traveling towards the shore. The role of Swash zone is influenced...

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...

Nowadays, rivers are impacted by different human activities and highly regulated. To rehabilitate these systems, spatial and process-based analyses of rivers are essential. Hydrodynamic models are sophisticated tools in this regard and instream topography is one of the most important input of these models. To represent hyperspatial topography and b...

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...

Spillways play an important role in the safety of dams. To ensure the safety of dams, spillways should be designed considering oods with long return periods. To increase the discharge capacity of a spillway, a designer can increase the crest length using the labyrinth spillway. For high head conditions, the local submergence may decrease the eecien...

Spur dikes are training structures used for river banks protection. The failure of these structures is due to excessive local scour. Velocity measurements were conducted to investigate the effect of spur dike location on the flow field around a spur dike located in a 90°. ADV apparatus with 50 HZ sampling rate was used to measure the 3D instantaneo...

با توجه به روند رو به رشد جمعیت و نیاز به افزایش تاسیسات آبرسانی و انتقال فاضلاب، ناگزیر به بهره گیری از سیستم های جدید و در عین حال اقتصادی برای هدف مورد نظرمان هستیم. یکی از سازه های انتقال آب و فاضلاب، سازه های شیب شکن گردابه ای است. نوع گردابه ای این سازه ها به دلیل قابلیت کنترل بیشتر جریان و استهلاک انرژی آن، بیشتر مورد کاربرد قرار گرفته است....

The photo induced properties of self-cleaning materials can be attributed to the synergy of two fundamental photochemical phenomena, oxidation-reduction reaction of adsorbed substances and photo induced superhydrophilicity, which occur on the surface of photo catalysts. The photo-induced properties make these materials able to mimic the tunable wet...

The results of experiments on the local scour due to free fall jets are presented in this paper. Experiments were conducted for various values of the densimetric Froude number, the relative tailwater depth, the relative drop height and the relative sediment size. It has been found that by increasing the sediment non-uniformity parameter the scour h...

Experiments involving both a circular wall jet and an impinging jet were conducted, as occurring at irrigation control structures or at dams with combined crest and low-level spillways. The effects of the non-dimensional parameters on the scour hole dimensions have been investigated. It was found that the effect of the expansion ratio of the channe...

On account of viscosity and surface tension effects the discharge equation for flow over a rectangular sharp crested weir loses its significance at low heads. The low head discharge prediction methods in usage are based on multiplying correction factors which are either dimensionally inhomogeneous, or have to be obtained from a graph which makes th...

This paper deals with the study of the geometry of the scour hole and topography of the bed around a T-shaped unsubmerged spur dike located in a 90° bend. The experiments were carried out in a channel with a 90° bend. Uniform sediments having an average diameter of 1.28 mm were used under clear-water scour conditions. The effects of parameters like...

Results are presented of 80 experiments on the time variation of scour in uniform bed materials due to a sedimentladen free-overfall jet. It was found that the scour hole characteristics (i.e. the depth of scour, the width of the scour hole, the length of the scour hole and the height of the ridge formed downstream of the scour hole) are functions...

In the past few decades, the use of spur dikes for stability of the outer banks of rivers has attracted the attention of hydraulic engineers. Setting spur dikes in the flow’s direction leads to local scour around the spur dike and changes the topography of the bed. This paper deals with the study of the temporal variation of the scour hole and topo...

To alleviate the scour depth around a series of existing spur dikes (SDs), a protective SD located upstream of the first was experimentally investigated. To determine the optimal design parameters, various values, lengths, angles and the spacing of a protective SDs were experimentally tested under different clear-water conditions in a straight rive...

The results of experiments on the scour due to an upwards inclined circular wall jet are presented. Outflow water jets with a velocity of 0.5-1.67 m/s at different angles of 0-208 using two pipes of 1 and 2 cm inner diameter were considered. The tailwater depth varied from 3 to 22 cm. The scour process due to horizontal and inclined wall jets is pr...

The purpose of this study is to simulate flow pattern in a 90°bend experimentally and numerically. The numerical model used in this study is SSIIM 1.1. The k–ε model was used to predict the turbulence and the SIMPLE method was used to compute the pressure. For verification of the results of the numerical model the experimental data was used. The fl...