Publications de Roham Bakhtyar

Impacts of wave and tidal forcing on 3D nearshore processes on natural beaches. Part II. Sediment transport

This is the second of two papers on the 3D numerical modeling of nearshore hydro- and morphodynamics. In Part I, the focus was on surf and swash zone hydrodynamics in the cross-shore and longshore directions. Here, we consider nearshore processes with an e ...

Techno-Press2016

Impacts of wave and tidal forcing on 3D nearshore processes on natural beaches. Part I: Flow and turbulence fields

David Andrew Barry, Roham Bakhtyar

The major objective of this study was to develop further understanding of 3D nearshore hydrodynamics under a variety of wave and tidal forcing conditions. The main tool used was a comprehensive 3D numerical model – combining the flow module of Delft3D with ...

Techno-Press2016

Direct effects of dominant winds on residence and travel times in the wide and open lacustrine embayment: Vidy Bay (Lake Geneva, Switzerland)

Ulrich Lemmin, Florence Bonvin, David Andrew Barry, Tamar Kohn, Roham Bakhtyar, Amir Mehdi Razmi

Numerical simulations were carried out to determine the residence (or flushing) time of water in Vidy Bay (north shore of Lake Geneva) for different meteorological conditions. A hydrodynamic model (Delft3DFLOW) was applied to simulate the flow field in the ...

Springer Verlag2014

Transport of variable-density solute plumes in beach aquifers in response to oceanic forcing

David Andrew Barry, Alessandro Brovelli, Clare Robinson, Roham Bakhtyar

A comprehensive numerical study was undertaken to investigate transport of a variable-density, conservative solute plume in an unconfined coastal aquifer subject to high and low frequency oceanic forcing. The model combined variable-density saturated flow ...

Elsevier2013

Experiments and numerical modeling of baffle configuration effects on the performance of sedimentation tanks

David Andrew Barry, Roham Bakhtyar, Amir Mehdi Razmi

The hydraulic efficiency of sedimentation basins is reduced by short-circuiting, circulation zones and bottom particle-laden jets. Baffles are used to improve sediment tank performance. In this study, laboratory experiments were used to examine the hydrody ...

National Research Council Canada2013

Two-phase flow modeling of the influence of wave shapes and bed slope on nearshore hydrodynamics

David Andrew Barry, Roham Bakhtyar, Amir Mehdi Razmi

An Eulerian two-phase flow model (air-water) was used to simulate nearshore hydrodynamic processes driven by wave motion. The flow field was computed with the Reynolds-Averaged Navier-Stokes equations in conjunction with the Volume-Of-Fluid method and the ...

Coastal Education and Research Foundation2013

Numerical experiments on interactions between wave motion and variable-density coastal aquifers

David Andrew Barry, Alessandro Brovelli, Roham Bakhtyar

A comprehensive two-dimensional (cross-shore) process-based numerical model of nearshore hydrodynamics (based on the Navier-Stokes equations, k-ε turbulence closure and the Volume-Of-Fluid method), beach morphology, and variable-density groundwater flow (S ...

Elsevier2012

Numerical experiments on breaking waves on contrasting beaches using a two-phase flow approach

David Andrew Barry, Roham Bakhtyar

A mechanistic understanding of beach environments needs to account for interactions of oceanic forcing and beach materials, in particular the role of waves on the evolution of the beach profile. A fully coupled two-phase flow model was used to simulate nea ...

Elsevier2012

An application of Evolutionary Optimization Algorithms for Determining Concentration and Velocity Profiles in Sheet flows and Overlying Layers

David Andrew Barry, Roham Bakhtyar

The Particle Swarm Optimization (PSO) method and the Genetic Algorithm (GA) were used to derive formulas for determining the velocity and concentration profiles in sheet flows. Specifically, these evolutionary optimization algorithms were used in conjuncti ...

Asme-Amer Soc Mechanical Eng2012

Numerical experiments of breaking waves on dissipative and intermediate beaches using a two-phase flow method

David Andrew Barry, Roham Bakhtyar

A fully coupled two-phase flow model was developed to simulate nearshore fluid-sediment turbulent flow. It includes the Reynolds-Averaged Navier-Stokes equations and turbu¬lent stress closures for each phase, and accounts for inter-granular stresses. It wa ...

2011

Wave-induced watertable fluctuations, sediment transport and beach profile change: Modeling and comparison with large-scale laboratory experiments

David Andrew Barry, Alessandro Brovelli, Roham Bakhtyar

Coastal groundwater systems can have a considerable impact on sediment transport and foreshore evolution in the surf and swash zones. Process-based modeling of wave motion on a permeable beach taking into account wave-aquifer interactions was conducted to ...

Elsevier2011

Numerical Simulation of Two-Phase Flow for Nearshore Hydrodynamics under Wave-Current Interactions

David Andrew Barry, Roham Bakhtyar, Amir Mehdi Razmi

Surf and swash zone hydrodynamics are complex, being composed of a highly energetic water-air mixture under periodically unsteady motion. Wave-current interactions have a major effect on the results of hydrodynamic simulations, and consequently on predicti ...

Coastal Education and Research Foundation2011

Cross-shore sediment transport estimation using fuzzy inference system in the swash zone

Roham Bakhtyar

The interactions between fluid and sediment in the swash zone dominate the erosion or accretion of the beach, and they act as boundary conditions for nearshore hydrodynamic and morphodynamic models. Thus, the evaluation of sediment transport is of particul ...

2011

Two-phase hydrodynamic and sediment transport modeling in the nearshore zone

David Andrew Barry, Roham Bakhtyar

2011

Numerical simulation of two-phase flow for sediment transport in the inner-surf and swash zones

David Andrew Barry, Roham Bakhtyar

A two-dimensional two-phase flow framework for fluid- sediment flow simulation in the surf and swash zones was described. Propagation, breaking, uprush and backwash of waves on sloping beaches were studied numerically with an emphasis on fluid hydrodynamic ...

Elsevier2010

Effects of wave forcing on a subterranean estuary

David Andrew Barry, Clare Robinson, Roham Bakhtyar

Wave and tide are important forcing factors that typically co-exist in coastal environments. A numerical study was conducted to investigate individual and combined effects of these forces on flow and mixing processes in a near-shore subterranean estuary. A ...

American Geophysical Union2010

Discussion of “Application of a Nonstandard Explicit Integration to Solve Green and Ampt Infiltration Equation” by Damodhara R. Mailapalli, Wesley W. Wallender, Rajendra Singh, and Narendra S. Raghuwanshi

David Andrew Barry, Roham Bakhtyar

Mailapalli et al. (2009) presented an explicit numerical scheme for calculation of solutions to the 1D Green and Ampt (1911) infiltration equation. They compared their numerical solution to a numerical solution obtained using the Newton-Raphson method (e.g ...

2010

Air-water two-phase flow modeling of turbulent surf and swash zone wave motions

David Andrew Barry, Roham Bakhtyar, Amir Mehdi Razmi

Wave breaking and wave runup/rundown have a major influence on nearshore hydrodynamics, morphodynamics and beach evolution. In the case of wave breaking, there is significant mixing of air and water at the wave crest, along with relatively high kinetic ene ...

Elsevier2010

Numerical simulation of surf-swash zone motions and turbulent flow

David Andrew Barry, Roham Bakhtyar

A two-dimensional numerical model was presented for the simulation of wave breaking, runup and turbulence in the surf and swash zones. The main components of the model are the Reynolds-Averaged Navier-Stokes equations describing the average motion of a tur ...

2009

Optimization of cascade stilling basins using GA and PSO approaches

David Andrew Barry, Roham Bakhtyar

In high head dams, the kinetic energy at the spillway toe is very high and the tail-water depth available for energy dissipation is relatively small. Cascade stilling basins are energy dissipation systems for high head dams, the design of which is based on ...

2009