Mohammad Saud Afzal

Indian Institute of Technology Kharagpur | IIT KGP · Department of Civil Engineering

A three-dimensional (3D) computational fluid dynamics (CFD) model is used to calculate the scour and the deposition pattern around a pier for two different boundary conditions: constant discharge and regular waves. The CFD model solves Reynolds-Averaged Navier–Stokes (RANS) equations in all three dimensions. The location of the free-surface is repr...

The effect of three-dimensional wave-induced streaming on the seabed boundary layer is investigated for following and opposing waves and current where the wave propagation forms a nonzero angle with the current. It is shown that the seabed boundary layer flow results from an interaction between the classical wave-current interaction (reducing the m...

The scour and deposition pattern around an abutment under constant discharge condition is calculated using a three dimensional (3D) Computational Fluid Dynamics (CFD) model. The Reynolds-Averaged Navier Stokes (RANS) equations are solved in three dimensions using a CFD model. The Level Set Method (LSM) is used for calculation of both free surface a...

This paper presents three dimensional (3D) numerical modeling of local scour around a single pile under the combined action of waves and currents. A semi-coupled hydrodynamic and morphological model (REEF3D) is used in this study which solves the Reynolds-averaged Navier–Stokes (RANS) equation with k-ω turbulence model closure. The Exner equation i...

This study explores the scour phenomenon around a submerged square pile under the combined influence of waves and currents. To this end, a three-dimensional Computational Fluid Dynamics model was developed. The numerical model solves the Reynolds-averaged Navier-Stokes (RANS) equations with k-ω turbulence closure model. The Level-Set method is util...

This paper conducts a thorough numerical investigation into the three-dimensional hydrodynamic interactions of wave-current flow with a square cylinder. Utilizing the open-source computational fluid dynamics modeling tool, the study considers variations in the Keulegan–Carpenter (KC) number, wave-current parameter ( U c w = U c / U m) (Uc and Um ar...

Development of a numerical model to study the hydrodynamics and sediment transport phenomenon is essential in venturing into the field of coastal engineering applications. In the framework of OpenFOAM, a solver which can simulate simultaneously waves and current and its impact on sediment transport is nonexistent. Here, a semi-coupled sediment tran...

The paper presents three-dimensional (3D) simulations conducted to study scour around a pair of twin piles arranged in different skew angle (α) configurations under combined wave-current flow conditions, utilizing a computational fluid dynamics (CFD) model, REEF3D. The Reynolds-averaged Navier-Stokes (RANS) equation is solved using the k-ω turbulen...

The present study investigates the scour at vertical-wall abutments under a strong current-dominated combined wave-current and current-only environment using experiments and computational fluid dynamics (CFD) modeling. The CFD modelling is performed using an open-source three-phase numerical model (REEF3D), which solves Reynolds-Averaged Navier Sto...

The present study employs numerical simulations to investigate vertical wall abutment scour with different aspect ratios (B/L, where B is the abutment length in the flow direction, and L is the abutment length transverse to the flow direction) under the combined effect of waves and current. The numerical model solves the Reynolds-averaged Navier–St...

A numerical investigation of hydrodynamics around a monopile foundation is presented in the paper. An open-source CFD program REEF3D is used for the present study. The REEF3D model solves the Reynolds-averaged Naiver-Stokes equation with k-w turbulence closure to obtain the flow hydrodynamics. The code utilizes a staggered cartesian grid system. Al...

The development of pier scour in coastal environments severely affects the bridge’s stability. Therefore, estimating pier scour around the vertical cylinder is important for the safety of the bridge structure. The estimation of pier scour depth in combined wave-current conditions has become a challenging task for researchers in recent times. The ex...

Most bridge failures occur due to the development of scour holes around the abutment and pier. Therefore, accurate prediction of abutment scour depth is critical for designing and maintaining bridges to ensure their safety and longevity. Traditional methods for predicting abutment scour depth, such as empirical formulas and physical models, have ac...

This study utilizes three-dimensional simulations to investigate scour in combined wave–current flows around rectangular piles with various aspect ratios. The simulation model solves the Reynolds-averaged Navier–Stokes (RANS) equations using the k–ω turbulence model, and couples the Exner equation to compute bed elevation changes. The model also em...

Waves of large size can damage offshore infrastructures and affect marine facilities. In coastal engineering studies, it is essential to have the probability estimates of the most extreme wave height expected during the lifetime of the structure. This study predicts significant wave height using the machine learning (ML) technique with generalized...

In early January 2020, the causal agent of unspecified pneumonia cases detected in China and elsewhere was identified as a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and was the major cause of the COVID-19 outbreak. Later, the World Health Organization (WHO) proclaimed the COVID-19 pandemic a worldwide public health emergenc...

Flow past circular cylinder modified by grooves is one of the passive control techniques to control the drag and lift forces. The presence of grooves tends to reduce the hydrodynamic drag and lift. The aim of this work was to numerically investigate the influence of a single groove modification on a circular cylinder and how it was impacting the hy...

The flow past cylinders is considered as a classical problem of fluid mechanics owing to its numerous engineering applications. Researchers, in the past, while studying the hydrodynamic aspects around cylinders of different cross-sections considered no-slip boundary condition on the cylinder surface. However, very little is known when the flow i...

This article presents a review of the state of research on bridge pier scour under combined wave–current flow. The hydrodynamics and scour around the bridge pier under combined wave–current flow have been explained in detail based on the information available in the literature. The impact of relative flow velocity (Ucw), Keulegan–Carpenter number (...

In the present work, an effort has been made to delineate the effect of the position of an isolated elliptical cylinder, placed in an infinite rectangular flow domain, on the various hydrodynamic parameters. Numerical experiments pertaining to flow past a two-dimensional elliptical cylinder are performed by making use of the open-source f...

An analysis of forces for flow around an elliptic cylinder at low Reynolds number has been presented in this work. The finite-volume based open source code OpenFOAM is used for the numerical simulations. pimpleFoam solver is used to solve Navier- Stokes equations for incompressible flow. The combined effects of aspect ratios (AR = 0.2, 0.3, 0.4, 0....

The investigation of the flow characteristics around cylinders of different cross-sections is considered as a classical problem of fluid mechanics. Owing to significant engineering applications like deducing the vortex-shedding associated with the wind flow around cylindrical high-rise structures, laying of underwater pipelines and the hydrodynamic...

With the advancement of the computing facilities, meshless techniques have become a new arena of research for the computational scientists. Smooth particle hydrodynamics (SPH), a popular mesh free method, has shown significant potential in the numerical reproduction of many complex problems associated with environmental hydraulics. The present pape...

This paper presents a numerical study of the three-dimensional hydrodynamic characteristics of oscillatory flow past a square cylinder including the effect of the variation of blockage ratio and the Keulegan-Carpenter (KC) number on those characteristics. The oscillatory flow is simulated using an open-source Computational Fluid Dynamics (CFD) mode...

The whole valley corresponding to a dam is involved during a dam break. Therefore, buildings and roads become obstacles to the flow in that region. This study presents a numerical and experimental study of hydrodynamics influence on waves generated during dam break due to such obstacles. The case is simulated by the LSM based CFD program, i.e., REE...

The population growth and GDP in India are at risk due to riverine flooding. Therefore, flood inundation mapping is required to understand and manage the floodplain and mitigate the subsequent impacts of riverine flooding. The flood simulation models were developed to calculate the elevation of water surfaces that occur during a flood event. A one-...

The water quality measurement of marine water is a key research topic for environmental and ocean modelers in the past several decades. Marine water quality is mainly described by its chemical, physical and biological properties. According to the Environmental Protection Department (EPD), Hong Kong, the chemical and physical measurements are integr...

This book (Vol. - I) presents select proceedings of the first Online International Conference on Recent Advances in Computational and Experimental Mechanics (ICRACEM 2020) and focuses on theoretical, computational and experimental aspects of solid and fluid mechanics. Various topics covered are computational modelling of extreme events; mechanical...

This book (Vol. II) presents select proceedings of the first Online International Conference on Recent Advances in Computational and Experimental Mechanics (ICRACEM 2020) and focuses on theoretical, computational and experimental aspects of solid and fluid mechanics. Various topics covered are computational modelling of extreme events; mechanical m...

The soil temperature within the Arctic coasts within the continuous permafrost is not widely measured; the temporal and spatial resolutions of the measured temperature observations are relatively high. In this study, we examined the methods to interpolate, hindcast and forecast temperature measurements within the active layer and shallow permafrost...

The propagation of waves in shallow waters is affected by the bottom topography unlike deep water waves of the coastal environment. Due to the interaction of the wave with bed topography, the wave transformation processes occur. Refraction, diffraction, shoaling, and breaking are the wave transformation processes that occur in the coastal environme...

The continuous shift of shoreline boundaries due to natural or anthropogenic events has created the necessity to monitor the shoreline boundaries regularly. This study investigates the perspective of implementing artificial intelligence techniques to model and predict the realignment in shoreline along the eastern Indian coast of Orissa (now called...

Weirs serve the dual purpose of flow measurement and flow regulation in open channels. In the past, weirs of improved plan form have been used to increase the discharge through the weir and to regulate the afflux. This study presents the results of the experiments that were carried out to investigate the discharge capacity of a multi-cycle W-form l...

A comprehensive review of the local scour due to vortical flow around a cylindrical bridge pier under steady current is presented in this paper. The mechanism of the formation of vortices, the size, velocity and strength of horseshoe vortex (HSV), formation of the HSV by the separation of laminar and turbulent boundary layer and the scour around a...

Arctic coastal erosion demands more attention as the global climate continues to change. Unlike those along low-latitude and mid-latitude, sediments along Arctic coastlines are often frozen, even during summer. Thermal and mechanical factors must be considered together when analysing Arctic coastal erosion. Two major erosion mechanisms in the Arcti...

In this paper, a mathematical equation is developed for the equilibrium scour depth considering an arbitrary shape of the scour hole around a pier under the action of collinear waves and current. A power-law current velocity profile is assumed for the purpose of the analysis. The equilibrium scour depth is obtained by equating the work done by the...

This paper sheds light on the formulation of a new equilibrium local scour depth equation around a pier. The total bed materials removed from the scour hole due to the force exerted by the flowing fluid after colliding with the pier in the flow field are estimated. At the equilibrium condition, the shape of the scour hole around the pier may take a...

Abstract: In this review article, the current status of research on pier scour under waves is presented. This includes a summary of different bridge failure events due to scour, scour mechanism, scour depth predictors under waves, influence of pier shape on scour depth formation, shape of scour hole around piers, and many others. Further, this arti...

Arctic permafrost constitutes one-third of the world’s coastline that is characterized by the presence of ice and cohesive sediments. Erosion of Arctic coastline has adverse impacts on social life and economy of the communities living in the area. There are two main processes of coastal erosion in the Arctic regions: Thermodenudation and thermoabra...

The objective of the work carried out in the present thesis is to obtain new insights into wave- current seabed boundary layers by studying the wave-current interaction for the general case of a non-zero angle between the waves and the current using numerical modelling. The first part of this work focuses on the hydrodynamics, while the second part...

Two-dimensional (2D) numerical simulations are performed to investigate free surface waves past two semi-submerged horizontal circular cylinders in tandem. The 2D simulations are carried out by solving the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations with the k-ω turbulence model. The level set method is employed to model the free-sur...

The three-dimensional numerical model REEF3D is used to simulate the detailed flow field and sediment transport around a non-slender cylinder under regular waves. The location of the free surface is calculated with the interface capturing level set method. The model is used as a numerical wave tank. Waves are generated at the inlet boundary, which...

Sediment transport in wave-current bottom boundary layer under linear propagating waves at an angle with the current have been investigated for different sediment grain sizes. The model uses the incompressible unsteady Reynolds-averaged Navier-Stokes (URANS) equations and the continuity equation as the governing equations for momentum and mass cons...

Effect on sediment transport due to veering of mean velocity in the seabed boundary layer has been investigated using numerical simulations. The effect on veering and hence the sediment transport pattern due to varying angle between the waves and current is presented. The flow results because of the classical wave-current seabed interaction. The cl...

Contraction scour is a type of general scour that occurs due to a reduction in the channel cross-section. This is observed where the flow is constricted due to the placement of structures like bridg- es abutments and other onshore/offshore structures. The flow accelerates in constrictions, which increases the bed shear stress and increases the turb...

Stability of offshore structures can be threatened by local scouring which could ultimately lead to their failure. As a consequence, knowledge of the scouring mechanism and the accurate prediction of the characteristic scour geometry is very important for the design of such structures. A three-dimensional computational fluid dynamics model is used...

The sediment transport module of REEF3D is used to calculate the scour and the deposition pattern for abutment, pier and contraction under constant discharge and for pier under waves. The time development of scour for all these cases is also observed. To this effect, the Reynolds Averaged Navier Stokes (RANS) equations are solved in all three dimen...