PhD position: Hybrid particle-continuum modelling of backward erosion piping in heterogenous soil layers

In dike safety assessment, it is important to understand how failure processes at different scales contribute to flood risk. In the case of BEP, this includes erosion at the pipe tip, continued erosion along the growing pipe, and the transport of sediment under changing hydraulic conditions. These processes are driven by local and regional groundwater flow, which is strongly affected by variations in the shallow subsurface. Existing models often rely on (semi-)empirical rules, such as the Sellmeijer criterion, to predict pipe growth and the critical hydraulic head. However, because the underlying BEP mechanisms are still not fully understood, the main parameters controlling pipe development remain uncertain. As a result, predictions of when failure will occur can vary significantly.

Within Work Package 3, Upscaling BEP models across scales, you will address the following scientific challenge: incorporating BEP mechanisms into continuum-based models in which the interaction between pipe growth at the micro-scale and groundwater flow at the local and regional scale is explicitly represented. You will use an existing concurrent multi-scale modelling framework that combines the finite element method (FEM) and the discrete element method (DEM).

You will work closely with two other PhD candidates who will study how 3D subsurface variability influences BEP behaviour, using both simplified and advanced BEP models within a unified probabilistic framework. This approach makes it possible to combine models with different levels of detail and computational cost, and to use them efficiently for quantifying the risk of dike failure caused by backward erosion piping.

PhD position: High resolution micro-scale modelling of Backward Erosion Piping

A key threat to dike stability is Backward Erosion Piping (BEP), a complex process in which seepage flow through the dike foundation progressively concentrates into internal erosion channels (“pipes”) caused by sand particle erosion, particularly during high-water events. In the worst-case scenario, such pipes can develop into breaches. Current assessment methods use overly simplified models that don’t account for the intricate physics beneath the surface. Digital Dikes addresses this critical challenge by developing advanced numerical models that capture the 3D nature of BEP and the variability of soil and water conditions. The program will train 14 young researchers to develop, apply and validate novel modelling methodologies to assess dike safety, in collaboration with industry, government, and international partners.

Project details:
Internal erosion mechanisms remain poorly understood, particularly at the microscale, which limits the development of reliable models for real-life dikes. Two distinct processes govern Backward Erosion Piping: primary erosion (Darcy-driven erosion at the pipe tip) and secondary erosion (tangential erosion along the pipe walls), which are responsible for the upstream propagation and for the widening of the erosion channel, respectively.

This PhD project will employ advanced particle–fluid simulation tools to model microscale piping erosion, with a particular focus on primary erosion mechanisms. The foreseen numerical simulations methods are the Discrete Element Method (DEM) for the granular soil and the Lattice Boltzmann Method (LBM) for the seepage flow at the pore scale. This coupled framework can resolve complex pore-scale fluid flow and effectively captures particle motion driven by erosion. The study will target:

• Primary erosion at the upstream-propagating pipe tip;
• Three-dimensional pipe networks, where secondary streams converge into the primary pipe, forming meandering pathways as the pipe advances;
• The influence of small-scale heterogeneities (e.g., local density variations) on the development of meandering patterns.

The overarching objective is to establish connections between soil characteristics (particle size distribution, initial density, and pressure), local heterogeneity, and, in turn, the 3D advancement of the pipe tip. By comparing different soil conditions, the study will assess how primary erosion is affected by the formation of 3D branches in relation to soil properties.

This project necessitates high-performance computing (HPC) methods and infrastructures to enable, for the first time, a three-dimensional particle-scale numerical investigation of BEP primary erosion.

PhD position on Dissecting Algorithmic Collusion

Governments and regulatory bodies around the world are discussing how to create laws that ensure artificial intelligence (AI) is used fairly and responsibly. One growing concern is that algorithms could learn to work together in ways that harm society, for example, by raising prices. In this project, you will provide a rigorous foundation for these discussions by examining if and how certain types of algorithms can learn such collusive behaviour. You will develop mathematical tools to measure how likely an algorithm is to engage in this kind of coordination by studying how and what it learns and then use these tools to analyze (using theory and simulations) how changes to three key areas can affect an algorithm’s tendency to collude: (1) its learning objective, (2) the representations of its environment, and (3) changes in the algorithmic metagame. By studying these factors, we will improve understanding regarding which design choices lead to harmful coordination and may need to be regulated in the future.

Postdoc position on Development of Hemodialysis membranes based on novel polymers

Within the Advanced Organ Bio-engineering and Therapeutics (AOT), at the University of Twente, The Netherlands, we have a vacancy for a Postdoctoral researcher.

Research description: Most patients with kidney failure receive dialysis therapy, because of a donor organ shortage. Unfortunately, current filters cannot remove all toxins from patients’ blood, especially protein-bound toxins, leading to high mortality and poor quality of life. Moreover, dialysis therapy requires lots of water. This research project aims to develop new hemodialysis membranes and dialyzers for improved dialysis therapy and to assess their commercial and technological feasibility.

Functioneel beheerder

De dienst Centre for Educational Support (CES) verzorgt alle onderwijsondersteunende activiteiten van de Universiteit Twente. Binnen deze dienst is de afdeling Information Management (IM) verantwoordelijk voor het functioneel beheer van de student- en onderwijs informatiesystemen. Deze systemen ondersteunen zowel het primaire onderwijsproces als de onderwijsondersteunende processen voor Bachelor- en Masterstudenten, exchange onderwijs (studenten) en Lifelong Learning (professional learners).

Optimalisering en digitalisering van processen zijn belangrijke thema’s voor de Universiteit Twente en binnen CES. Onze processen worden zoveel mogelijk geautomatiseerd ondersteund en er zijn volop ontwikkelingen op gebied van optimalisatie en innovatie om het onderwijs nog beter te kunnen ondersteunen. Functioneel beheer speelt hierin een belangrijke rol en daarom zoeken wij versterking voor het functioneel beheer van ons Studenten Informatie Systeem Osiris.

Als functioneel beheerder ben je een schakel tussen de vraag- en aanbodkant en heb je afwisselende taken zoals:

• het inrichten van systemen en het opstellen van bijbehorende conventies voor vulling/gebruik;
• het afhandelen van gebruikersvragen, het instrueren van gebruikers en het opstellen en onderhouden van instructiemateriaal;
• het signaleren, beoordelen en oplossen van knelpunten;
• het doorvoeren van wijzigingen in functionaliteiten en in configuratie binnen het systeem, het doorvoeren van releases en het testen van wijzigingen en releases;
• deelname aan en/of aansturing van verbeter- en verandertrajecten;
• het uitvoeren van procesanalyses en advisering over procesoptimalisatie, waarbij je verantwoordelijk bent voor het optimaliseren en automatiseren van bestaande en nieuwe processen;
• het zorgen voor een goede samenwerking in de beheerketen t.b.v. efficiënte en passende dienstverlening.