Gergely Torok

Budapest University of Technology and Economics · Department of Hydraulic and Water Resources Engineering

3D numerical models are increasingly used to simulate flow, sediment transport and morphological changes of rivers. For the simulation of bedload transport, the numerical flow model is generally coupled with an empirical sediment transport model. The application range of the most widely used empirical models is, however, often limited in terms of h...

The aim of this study is to introduce a novel method which can separate sand- or gravel-dominated bed load transport in rivers with mixed-size bed material. When dealing with large rivers with complex hydrodynamics and morphodynamics, the bed load transport modes can indicate strong variation even locally, which requires a suitable approach to esti...

In this study, the field measurement-based validation of a novel sediment transport calculation method is presented. River sections with complex bed topography and inhomogeneous bed material composition highlight the need for an improved sediment transport calculation method. The complexity of the morphodynamic features (spatially and temporally va...

The composition or bed material plays a crucial role in the physical hydromorphological processes of fluvial systems. However, conventional bed material sampling methods provide only pointwise information, which can be inadequate when investigating large rivers of inhomogeneous bed material characteristics. In this study, novel, image-based approac...

A Duna-vízgyűjtő magyarországi részének felülvizsgált, 2015. évi vízgyűjtő-gazdálkodási terve („VGT2”) alapján legtöbb folyónkon medermélyülés figyelhető meg, amely magával vonja a vízszintek süllyedését. A legjelentősebb medermélyülés a Dráva folyón tapasztalható (kb. 3-4 cm/év), amit a természetes mederváltozási folyamatok mellett különféle inten...

Exploring the effects of bank vegetation on fluvial morphodynamics has long been an essential part of fluvial morphodynamic-related research. In a practical sense, a central question is: does increased vegetation density increase or decrease the channel width? Several aspects concerning the role of vegetation may result in examples of both width de...

Our study is based on 3D CFD model studies of the impact of wing dams. We look for characteristics that are expected to play an important role (e.g., bed material, geometry) in the morphodynamic changes caused by such interventions. Based on these characteristics our 3D model tests can be performed. Using schematic 3D models with real morphodynamic...

Theanalysisofbed-loadmovementisessentialtounderstandmorphologicalprocessesinalluvialrivers.Betterunderstanding of these mechanisms may help predict changes occurring in the riverbed during flood events, estimate the effect of these events on riverbank ecosystems, and forecast the amount of sediment deposited in reservoirs. Mostly physical based samp...

The aim of this study is to introduce a novel method which can separate sand or gravel dominated bed load transport in rivers with mixed-size bed material. In engineering practice, the Shields-Parker diagram could be used for such purposes, however, the method has certain applicability limits, due to the fact that it is based on uniform bed materia...

The reliable prediction of morphological changes of rivers is of major need in the field of river engineering. Besides the conventionally used empirical procedures or hydraulic scale models, the numerical modeling is a progressively developing, but still not a widespreadly used tool. Moreover, the sediment transport modeling at non-uniform river be...

The aim of this study is to analyze the current morphological changes and to predict the potential future trends of a critical reach of the upper Hungarian Danube River. In this section of the river the morphological features have undergone significant changes, mainly due to human impacts, such as the construction of the Gabcikovo hydropower plant...

The spatial and temporal variability of the flow field, the sediment transport and the morphology of rivers directly influence navigation, habitat and flood risk. Therefore, the prediction of bed geometry changes is essential for rivers that are exposed to multiple use, such as the Danube River. Nowadays, the computational models are increasingly u...

A Duna hidromorfológiai állapotát nagymértékben befolyásolják a hajózási, energiatermelési, vízhasználati és egyéb célú emberi beavatkozások. A szabályozások okozta mederszűkítések, valamint a hordalékháztartás módosításai, mint pl. a vízgyűjtő területen való hordalék visszatartás és a hordaléktranszport folytonosságának megszakítása, a természetes...

In this study the local scour development around a single groin was investigated in the laboratory flume of the Norwegian University of Science and Technology (NTNU). The main goal of the experiments was to carry out a comprehensive data analysis on bed morphology, sediment transport, bed composition as well as hydrodynamics at conditions where bed...

A three-dimensional numerical model is introduced which is capable of reproducing the bed armoring process in rivers resulted by nonuniform bed material. The numerical flow model solves the 3D Reynolds Averaged Navier-Stokes equations with a k-ɛ turbulence model. The bed shear stress field is calculated over the study domain which serves as input d...

A confluence zone of two rivers of different sizes was chosen to study the complex flow and morphological features with up-to-date measurement techniques. The main stream is River Danube with a mean flow of 2000m 3/s, an average depth of 6m and an average width of 500 m, which approaches the junction zone in a sharp bend. The second river is a trib...