My name is Tess Homan. I work as an assistent professor in the Power and Flow group, Department of Mechanical Engineering, Eindhoven University of Technology. On this website you will find some of my current and past projects.
I'm always interested in recording 3D experiments in a smart way. This camera uses a diffuser plate instead of a lens to collect all 3D information on a 2D CCD chip. With the use of mathematics or deep learning the 3D scene can be reconstructed.
An acoustic levitator allows us to study droplets without interaction with a solid surface. It is important to understand the local environment (such as the acoustic boundary layer) to be able to interpret the results.
Bubbles rising in a liquid interact with each other, the walls, and the free-surface. How do they coalesce, especially when there are surfactants present in the liquid, and how can you break them up?
With a Fourier-based analysis it is possible to determine ensemble averages of the cell size in biological tissues, both in 2D and for 3D image stacks. Using generated images we analyzed valuable criteria for image acquisition settings to optimize accuracy.
Now that human cardiac cells can be produced from pluripotent stem cells (coming from blood or skin cells) a fast and easy way to analyze the beating patterns is needed. Our software finds arrhythmias and other anomalies from low time resolution movies.
The structure and distribution of sacromeres in cardiomyocytes play an essential role in the contraction efficiency of the heart. From fluorescent microscope images we can automatically detect parameters that separate cells from heart-patients and cells from healthy people.
Mechanical forces play a fundamental role in the development of tissues, such as during embryogenesis. We use soft probes to calculate the stresses inside MultiCellular Aggregates.
By continuousy injecting air into a granular bed, particles are lifted from the bed and mixed with the liquid above. If the suspended particles are heavier than the surrounding liquid they will settle back onto the bed. Because of the continuous ejection of particles an equilibrium will form.
Using a smart particle we perform direct acceleration measurements of a ball impacting on sand. We find detailed dynamics that cannot be seen in the position data such as, a downward acceleration due to the cavity collapse and the influence of interstitial air on the bed compressibility.
I did my PhD under supervision of Devaraj van der Meer and Detlef Lohse in the physics of fluids group at the university of Twente, on the influence of interstitial air on the movement of fine sand. Here you can find a pdf of my thesis.
The force that needs to be exerted to push a ball into a loose granular bed is lower when there is air present inside the bed. Pressurized, trapped air in front of the ball reduces the experienced drag.
The air pressure in the volumes above and below a loose granular bed is recorded during the impact of a metal ball. Air gets trapped inside a region of compressed sand around the ball, temporarily lowering the pressure above the bed.
As soon as an object hits the side wall of a container filled with very loose sand, the sand bed collapses. The amount the bed level changes decreases when the air pressure is lower. This indicates that interstitial air has a lubricating effect on the friction between grains.
Using an X-ray tomography system it is possible to "see" what happens inside a granular bed after the impact of an object. Different analyzation techniques give a reconstruction of the air cavity, the shape of the air bubble and the density changes in the sand.
If a metal ball impacts on fine, very loose sand, the bed behaves fluid like and the ball sinks into the bed. As soon as the cavity that is created behind the ball collapses a jet is created that rises above the bed surface.
When food is getting scarce a group of the single cellular organism Dictyostelium agglomerates. During my internship at the group of Wolfgang Losert at the university of Maryland I tracked the boundary movement of a Dicty cell to find the protrusions and retractions.
During an internship in the group of Tomas Bohr at the technical university of Denmark I investigated the formation and surface flow of a rotating polygon on a water surface.
The shape of the splash that forms after the impact of a ball on sand depends on the ambient pressure. When air is present, the splash becomes more vertical due to the suction of air flowing into the cavity created behind the ball.
9 - Tess Homan, Sylvain Monnier, Cécile Jebane, and Hélène Delanoë-Ayari, Measuring the average cell size in cellular tissues using Fourier transform, preprint arXiv:2008.12036 (2020)
8 - Melina Durande, Sham Tlili, Tess Homan, B. Guirao, F. Graner, and Hélène Delanoë-Ayari, Fast determination of coarse grained cell anisotropy and size in epithelial tissue images using Fourier transform, Physical Review E 99, 062401 (2019)
7 - Tess Homan and Devaraj van der Meer, Giant drag reduction due to interstitial air in sand, preprint arXiv:1607.07774 (2016)
6 - Tess Homan, Rob Mudde, Detlef Lohse, and Devaraj van der Meer, High-speed X-ray imaging of a ball impacting on loose sand, Journal of Fluid Mechanics 777, 690-706 (2015)
5 - Sylvain Joubaud, Tess Homan, Yoann Gasteuil, Detlef Lohse, and Devaraj van der Meer, Forces encountered by a sphere during impact into sand, Physical Review E 90, 060201 (2014)
4 - Tess Homan, Christa Gjaltema, and Devaraj van der Meer, Collapsing granular beds: The role of interstitial air, Physical Review E 89, 052204 (2014)
3 - Gabriel Caballero, Kevin Kelly, Tess Homan, Joost Weijs, Devaraj van der Meer, and Detlef Lohse, Suction of splash after impact on dry quick sand, Granular Matter 14, 179-184 (2012)
2 - Meghan Driscoll, Colin McCann, Rael Kopace, Tess Homan, John Fourkas, Carole Parent, and Wolfgang Losert, Cell shape dynamics: From waves to migration, PLoS Computational Biology 8, e1002392 (2012)
1 - Raymond Bergmann, Laust Tophoj, Tess Homan, Pascal Hersen, Anders Andersen, and Tomas Bohr, Polygon formation and surface flow on a rotating fluid surface, Journal of Fluid Mechanics 679, 415-431 (2011)
Power and Flow
Department of Mechanical Engineering
Eindhoven University of Technology
Gemini Zuid 2.136