Applications are welcomed for a joint PhD position KULeuven-UCLouvain starting October 1, 2021.

The objective of the project is to develop a better understanding of the soil-structure interaction during the installation and operational use of piles installed by vibratory driving for Offshore wind turbines. Semi-analytical and numerical models will be developed and calibrated using cyclic triaxial tests in conditions characteristic for offshore environments. The results of the models will be compared to reduced scale experiments of impact and vibratory driving for the installation and the extraction, but also the mechanical behavior of the pile subjected to cyclic loading under wind and wave loading. The developed methodology will be applied to actual case studies, aiming at a characterization of the soil-pile interaction and providing design guidelines.

To apply and get more detailed information, please see https://www.kuleuven.be/personeel/jobsite/jobs/60029856?hl=en

The Nottingham Centre for Geomechanics (NCG) is currently undertaking two large multi-disciplinary projects related to investigating the behaviour of coal-mining spoil materials with a focus on the geotechnical, sustainability, environmental, socio-economic and long-term management challenges. NCG brings together expertise from the worlds of civil, geotechnical, and mining engineering as well as mathematics and material sciences to solve all forms of soil and rock-related design and construction problems. The projects are funded by the European Commission Research Fund for Coal and Steel (RFCS) and include project partners from across Europe. We seek a highly motivated researcher to join our team to work on this challenging project.

We are looking to recruit a post-doctoral researcher who will support the work of these RFCS projects as well as support the wider work of the research group. We would consider any candidate with a strong fundamental geotechnical background.

Candidates should be inquisitive, with a strong interest in applied research, and the personality and drive to interact effectively with industry and project partners. They will have a first degree in Civil Engineering or cognate subject and will have been awarded a PhD (or have submitted their thesis for examination), ideally in an area of Geotechnical Engineering. The successful candidate will have good presentation and report writing skills. A good publication record will be an advantage but its absence should not hinder applications from those who have recently submitted their theses.

For application details see https://www.nottingham.ac.uk/jobs/currentvacancies/ref/ENG196421

Further information about the work of the Nottingham Centre for Geomechanics is available on www.nottingham.ac.uk/ncg/

Applications are invited for a PhD student at Delft University of Technology, to work on the development, implementation and application of a multiscale numerical testing environment for geomaterials.

For further details, please see the attached document or visit https://www.tudelft.nl/over-tu-delft/werken-bij-tu-delft/vacatures/details/?jobId=3083

« Fluid phase change simulation in porous and cracked media based on multimodal full-field measurements»

Project summary

The performance of reinforced concrete containment structures is analysed with respect to their ability to prevent a fluid from percolating through the wall barier. For concrete structures, the leaks break down into two flows, one of which passes through the porous networks of the cement matrix and the other passes through eventual cracks and crack network space. Conventionally, the fluids used to experimentally test the tightness are either liquid water or a neutral gas. In reality, the percolating fluid could be more complex, consisting of a multiphase mixture of air and hot water vapour.

The present project aims to pursue towards the quantitative experimental analysis and numerical multi-physics modelling of the two-phase (hot steam and air) flow and condensation processes during injection into fractured concrete material. Indeed, first ever experiments of in-situ quantitative visualization of vapour condensation in cracked concrete through high-speed neutron radiography have been performed revealing a complex interplay between pressure and sorption flow phenomena and a significantly different behaviour between dry and saturated sample.

Project summary

The project aims at studying numerically the rheological properties of suspensions of hard to soft spheres, dispersed in a Newtonian fluid, which are found in many industrial and geophysical processes. Using a DEM approach, and a recently developed model of lubricated contact, we will study the role of particle deformability, an essential ingredient which is usually overlooked in existing simulations. Deformability is crucial to regularize the divergence of the lubrication forces at contact, but its effects on the suspension rheology remain to be investigated in depth.

Our recently developed model of lubricated contacts [Chevremont et al., Powder Tech. 2020] produced new results related to the role of contact friction [Chevremont et al., Phys. Rev. Fluids 2019] and led to a complete set of constitutive relations for dense suspensions [Chevremont et al., arxiv.org/abs/2103.03718]. This model is implemented in the open source code yade-dem.org. We are now able to tackle efficiently the case of slightly deformable particles, for which lubrication, friction and deformability are strongly coupled.

At a macroscopic level, these effects are ignored by the established “μ(Iv)” constitutive model of hard sphere suspensions, as there is a new dimensionless number characterizing the ratio of viscous stresses to particle stiffness, the capillary number Ca. One goal of this project is to extend the μ(Iv) rheology to a phenomenological μ(Iv,Ca) rheology, which we will characterize by DEM simulations with systematic variations of the particle deformability, in a large range of volume fractions and shear rates.

We will also focus on viscous resuspension, which occurs when an external force field (typically gravity) is exerted on a flowing buoyant suspension, leading to gradients of volume fraction. This phenomenon is closely related to particle migration and the study of the transient regime from a homogeneous (non flowing) suspension to the re-suspended steady state will lead to improve existing continuum models by determining expansional viscosity.

This numerical project will be conducted in close relation to an ongoing experimental study.