Fluid dynamics of microplastics: fiber-flow interaction simulations to reduce 
plastic microfiber pollutant release 

Job description

Increasing scientific evidence and public awareness of risks from micro-plastics 
mean that new technologies are urgently needed to limit micro-plastics release 
in the aquatic environment. A large contribution to micro-plastics pollution 
comes from microfibers released from clothes in our washing machines, which 
cannot be completely filtered with current methods. We are working with an 
industrial partner to find a solution to the problem.

In this project, the PhD researcher will develop high-resolution simulations to 
investigate numerically the interaction of model fibers with the complex 
geometry of mesh-based filters.  The simulations will initially focus on single 
fibers interacting with curved solid walls. The simulations will be carried out 
with an immersed boundary method, using an appropriate "slender body" 
approximation for the fibers. Later the PhD student will investigate many 
fibers, assessing the effects of spontaneous fiber curvature, flexibility and 
multi-fiber interactions. Part of the project is also the development of 
analytical one-dimensional filtration models that take into account poly-
dispersity in fiber length and stiffness. The research group in which the PhD 
will work has developed codes for flexible particles (Salussolia, G., et al. 
"Simulation of interacting elastic sheets in shear flow: Insights into buckling, 
sliding, and reassembly of graphene nanosheets in sheared liquids." Physics of 
Fluids 34.5 (2022) and has almost 20 years of experience in the simulation of 
multiphase systems.

Developing the simulations will require a good understanding of fluid dynamics 
and numerical discretisation methods, so any prior research experience in these 
areas will be valuable. Furthermore, the PhD student will interact with other 
PhD students (also team members in the project) who will be carrying out 
experiments for validation, as well as with the industrial partner of the 
project. Therefore, the ability to communicate effectively and interact in a 
workgroup is highly valued. Most important is the student's motivation to use 
fluid dynamics knowledge to contribute solving an important societal challenge.

The preferred start date is September 2024.

The work will be carried out in the Process & Energy Department of TU Delft, 
within the research group of Dr. Lorenzo Botto. For information about Botto's 
research group and his scientific output, see 
https://bottogroup.wordpress.com/publications/. For information about the 
Process & Energy Department, see 
https://www.tudelft.nl/me/over/afdelingen/process-energy. The project is done in 
collaboration with Burak Eral, Process & Energy Department 
(https://erallab.com/index.php/burak-eral/) and Valeria Garbin, Chemical 
Engineering Department (https://www.tudelft.nl/tnw/over-
faculteit/afdelingen/chemical-engineering/principal-investigators/valeria-
garbin), who will supervise the experimental parts of the project.

Requirements

MSc degree in physics, engineering, mathematics or related areas. The MSc degree 
should have been awarded by the start of the PhD project.

A solid background in fluid dynamics, as evidenced by academic courses as well 
as research reports and papers (even unpublished).

Some experience with coding in a modern programming language and an interest in 
using computers for scientific discovery. Having attended courses in numerical 
methods is a plus.

Good scientific communication and writing skills.

The applicant should be open to collaboration, as the project requires 
coordination and synergy with other team members and external partners.

Doing a PhD at TU Delft requires English proficiency at a certain level to 
ensure that the candidate is able to communicate and interact well, participate 
in English-taught Doctoral Education courses, and write scientific articles and 
a final thesis. For more details please check the Graduate Schools Admission 
Requirements.

Conditions of employment

Doctoral candidates will be offered a 4-year period of employment in principle, 
but in the form of 2 employment contracts. An initial 1,5 year contract with an 
official go/no go progress assessment within 15 months. Followed by an 
additional contract for the remaining 2,5 years assuming everything goes well 
and performance requirements are met.

Salary and benefits are in accordance with the Collective Labour Agreement for 
Dutch Universities, increasing from € 2770 per month in the first year to € 3539 
in the fourth year. As a PhD candidate you will be enrolled in the TU Delft 
Graduate School. The TU Delft Graduate School provides an inspiring research 
environment with an excellent team of supervisors, academic staff and a mentor. 
The Doctoral Education Programme is aimed at developing your transferable, 
discipline-related and research skills.

The TU Delft offers a customisable compensation package, discounts on health 
insurance, and a monthly work costs contribution. Flexible work schedules can be 
arranged.

For international applicants, TU Delft has the Coming to Delft Service. This 
service provides information for new international employees to help you prepare 
the relocation and to settle in the Netherlands. The Coming to Delft Service 
offers a Dual Career Programme for partners and they organise events to expand 
your (social) network.

TU Delft (Delft University of Technology)

Delft University of Technology is built on strong foundations. As creators of 
the world-famous Dutch waterworks and pioneers in biotech, TU Delft is a top 
international university combining science, engineering and design. It delivers 
world class results in education, research and innovation to address challenges 
in the areas of energy, climate, mobility, health and digital society. For 
generations, our engineers have proven to be entrepreneurial problem-solvers, 
both in business and in a social context.

At TU Delft we embrace diversity as one of our core values and we actively 
engage to be a university where you feel at home and can flourish. We value 
different perspectives and qualities. We believe this makes our work more 
innovative, the TU Delft community more vibrant and the world more just. 
Together, we imagine, invent and create solutions using technology to have a 
positive impact on a global scale. That is why we invite you to apply. Your 
application will receive fair consideration.

Challenge. Change. Impact!

Faculty Mechanical Engineering

From chip to ship. From machine to human being. From idea to solution. Driven by 
a deep-rooted desire to understand our environment and discover its underlying 
mechanisms, research and education at the ME faculty focusses on fundamental 
understanding, design, production including application and product improvement, 
materials, processes and (mechanical) systems.

ME is a dynamic and innovative faculty with high-tech lab facilities and 
international reach. It’s a large faculty but also versatile, so we can often 
make unique connections by combining different disciplines. This is reflected in 
ME’s outstanding, state-of-the-art education, which trains students to become 
responsible and socially engaged engineers and scientists. We translate our 
knowledge and insights into solutions to societal issues, contributing to a 
sustainable society and to the development of prosperity and well-being. That is 
what unites us in pioneering research, inspiring education and (inter)national 
cooperation.

Click here to go to the website of the Faculty of Mechanical Engineering. Do you 
want to experience working at our faculty? These videos will introduce you to 
some of our researchers and their work.

Additional information

For more information about this vacancy, please contact Lorenzo Botto at 
l.botto@tudelft.nl.

Application procedure

Are you interested in this vacancy? Please apply no later than 14 July 2024 via 
the TU Delft job vacancy website. The vacancy can be reached directly via the 
link: https://www.tudelft.nl/over-tu-delft/werken-bij-tu-
delft/vacatures/details/?
nPostingId=6043&nPostingTargetId=17890&id=QEZFK026203F3VBQBLO6G68W9&LG=UK&langua
geSelect=UK&mask=external

In the application, please updload:

- A motivation letter specific to this vacancy in which you explain your 
interest in the project and your fit for our research group.

- Your Curriculum Vitae including names and contact information of 2 references.

Please note:

A pre-employment screening can be part of the selection procedure.

You can apply online. We will not process applications sent by email and/or 
post. But you can contact Lorenzo Botto at l.botto@tudelft.nl for informal 
enquires about the post. 

Please do not contact us for unsolicited services.