Interface-resolved simulations of dense particulate flows: Studies on sedimentation and slurry pipe flow

Dense suspension flows, both in the natural environment and industrial settings, are complex phenomena with significant implications. From rivers shaping landscapes to industrial processes involving slurry transport, these flows hold a prominent position in numerous sectors. This thesis delves into a specific facet of these intricate flows:...

Modelling and parameterizing the hydro- and morphodynamics of curved open channels

Meandering rivers are interesting features of the landscape due to their aesthetically pleasing forms. There is an abundance of scientific studies on meandering rivers, however, their behaviour is still not fully understood. The complexity of the flow, bed morphodynamics and bank stability, the related uncertainties in water and sediment motion,...

Meander dynamics: A reduced-order nonlinear model without curvature restrictions for flow and bed morphology

Reduced-order models remain essential tools for meander modeling, especially for processes at large length scales and long time scales, probabilistic simulations, rapid assessments, or when input data are scarce or uncertain. Present reduced-order meander models consider their dependent variables either as small-amplitude variations compared to...

Hydrodynamic processes in sharp meander bends and their morphological implications

The migration rate of sharp meander bends exhibits large variance and indicates that some sharply curved bends tend to stabilize. These observations remain unexplained. This paper examines three hydrodynamic processes in sharp bends with fixed banks and discusses their morphological implications: secondary flow saturation, outer-banks cells, and...

Meander dynamics: A nonlinear model without curvature restrictions for flow in open?channel bends

Despite the rapid evolution of computational power, simulation of meander dynamics by means of reduced and computationally less expensive models remains practically relevant for investigation of large?scale and long?term processes, probabilistic predictions, or rapid assessments. Existing meander models are invariantly based on the assumptions...

Saturation of curvature-induced secondary flow, energy losses, and turbulence in sharp open-channel bends: Laboratory experiments, analysis, and modeling

The paper investigates the influence of relative bend curvature on secondary flow, energy losses, and turbulence in sharp open-channel bends. These processes are important in natural streams with respect to sediment transport, the bathymetry and planimetry, mixing and spreading of pollutants, heat, oxygen, nutrients and biological species, and...

Flow and bathymetry in sharp open-channel bends: Experiments and predictions

This paper focuses on experiments and simulations conducted in very sharp open-channel bends with flat and equilibrium bathymetry, corresponding to the initial and final phases of the erosion and deposition processes, respectively. The study of flow in curved open bends is relevant for flow in natural river configurations, as most river reaches...

Depth-Averaged Numerical Modeling for Curved Channels

Without some correction for the interaction between lateral curvature and vertically nonuniform velocity, depth-averaged numerical models cannot predict the gradual migration of high velocity toward the outside of channel bends. Conventional depth-averaging does not account for the curvature-induced secondary flow that gives rise to the...

Improved simulation of main flow and secondary flow in a curved open channel

For the computation of depth averaged flows in tidal channels and rivers a recently developed fully implicit finite difference method of the ADI-type proved vastly superior to the partly explicit variants, commonly used. The fully implicit variant allowed a relatively large time step in combination with arealistic lateral diffusion coefficient....

Measurements of the rate of adjustment of the secondary flow in a curved open channel with varying discharge

Prediction of bottom changes in rivers and tidal channels require a thorough knowledge of the secondary flow, as this flow gives rise to bottom slopes transverse to the main flow direction. In the model used in this research, the computation of the secondary flow field is based upon an, independently computed, depth averaged main flow field. In...

Boundary-layer calculations on the leeward surface of a slender delta wing at incidence

The three dimensional flow field around delta wings with leading-edge vortex flow can be computed with panel methods. However, secondary flow separation may occur on the leeward surface of the wing. The associated free vortex sheet can be modeled in the potential flow calculation method, if the location of the secondary separation is provided by...

Simulation of main flow and secondary flow in a curved open channel

Knowledge of the secondary flow is essential for predictions about the morphology of alluvial bottoms in tidal channels. In this research the determination of the secondary flow is based on a known depth averaged velocity field. The depth averaged velocities must be computed with a high accuracy in order to make possible a reasonable...