Trajectory optimization with gradient descent for a variable-volume float

In the realm of fluid dynamics and particle transport, the control of particle trajectories represents a formidable challenge. It would be useful to be able to optimally navigate an oceanographic float from one pre-set location to another by solely changing its buoyancy. In this thesis, a first step in discovering whether this is possible and...

A Comprehensive Study of Magnetic Map-making Techniques for Navigation and Localization

Estimation of surface currents using optical satellite imagery of Kelvin wakes

Ocean currents play a crucial role in many scientific and industrial applications. Contemporary measurement techniques are limited in spatial coverage or spatial resolution. This study presents a proof-of-concept for a new measurement principle that merges optical satellite imagery of Kelvin wakes with data from the Automatic Identification...

Parameter and state estimation of a groundwater model using the Ensemble Kalman Filter

Groundwater is an essential ingredient in farming, knowledge about how this is expected to change over time can help farmers improve yields and save water. Predictions about the groundwater level can be made using a mathematical model. This model takes into account the precipitation and evaporation, the flux towards a deeper aquifer and flux to...

The application of differentiable programming frameworks to computational fluid dynamics

In recent years many automatic differentiable programming frameworks have been developed in which numerical programs can be differentiated through automatic differentiation (AD). Examples of these frameworks are Theano, TensorFlow and Pytorch. These frameworks are widely used in Machine Learning. AD also finds applications in the field of...

Where does plastic in the ocean come from?: Using the end location to find the likelihood of a possible start location of plastic particles in the ocean

In the ocean resides a large amount of plastic. This has severe environmental consequences for the oceans. To be able to clean up all this plastic the location of the plastic is needed. A lot of times plastic is cleaned up at the source, but to clean up here this location needs to be known. However, what if the start location is not known and...

A Particle-based Approach for Stochastic Modelling of Waves in the Near-shore Region

Processes occurring in the near-shore region operates on a small spatial and temporal scale. Simulations of these processes have long posed challenges for computational science, and to have accurate representations require a higher resolution. This results in computationally expensive models. This project aimed to investigate the possibility of...

The influence of fresh water discharge on coastal water levels: By a combination of physical and probabilistic models

Globally, at each river mouth freshwater is discharged to coastal waters. At each river mouth a freshwater plume is formed. These fresh water plumes are also known as the regions of freshwater influence (or ROFI’s). Furthermore, the freshwater plume will affect local coastal water levels. In order to improve global flood forecasting, research on...

Plastic litter in the ocean: Modeling of the vertical transport of micro plastics in the ocean

Plastic pollution is a big problem all over the world. Every year more plastic is produced, a lot of plastic litter is mismanaged and enters the ocean. It’s important to know where these plastics accumulate. With this information the problem can be quantified and the plastic litter can be cleaned up. In this project, the transport of micro...

Parametric wave growth in a frequency integrated wave model

Waves in coastal waters play a role in forecasting storm conditions, as boundary conditions for the assessment of coastal risk and in coastal structure design. Assessment of their impact can be made through numerical modeling. In a forecasting context, the CPU time of the wave model is decisive in its suitability. Recent years wave model...

A modified POD procedure with patterns in time for parameter estimation

Proper orthogonal decomposition (POD) is a well established model order reduction technique, however its efficiency is limited for advection dominated model. In this report, we explore a modified proper orthogonal decomposition procedure with patterns in time instead of the usual patterns in space. This modified procedure is more suitable for...

A modelling study on the residual circulation in the North Sea, with the focus on water fluxes through the Strait of Dover

In this master thesis the residual circulation in the North Sea is investigated. It has been shown that the numerical models used in this thesis (DCSMv5 and DCSMv6) give a rather low representation of the actual circulation pattern in the North Sea. The dominating forces which cause residual currents in the North Sea are the tidal forcings,...

Global tide model with DFlow-FM

This thesis is about the beginning of a global tide model in DFlow-FM, a project by Deltares. The first focus lay on finding the best grid that can be used for this model. We tried to grids, a rotated lat-lon grid and a squarely grid with local refinement. After calculating the RMS-value it was found that the local refined grid gave the best...