We have a new member in our group, Sangseung Lee! During his Phd in POSTECH, Sangseung made significant contribution on data-driven prediction of unsteady flows using deep learning. We are excited to further explore data-driven modeling of flow physics at KTH. Welcome Sangseung!
We are looking for motivated and enthusiastic postdocs to join our group! The topics include:
- numerical simulations of multiphase flows in porous media. See ad here
- experimental fluid mechanics with experience in PIV, LDV
- numerical simulations of wall-bounded turbulence
If you are interested in any of the above topics or have a project idea of your own that you think would fit in our res
The Young Academy, formed by the Royal Swedish Academy of Sciences in 2011, is an independent forum for younger, leading researchers from all research areas. Shervin will together with the academy focus on improving the academic system in Sweden for young scientists as well as engaging in outreach activities for youths with diverse backgrounds.
We are excited to have submitted the following at the APS this year:
“Roughness-like modulation of canonical wall-bounded turbulence using effective boundary conditions” (Seyed Morteza)
“Motion of contact line and reconfiguration of two-phase interface: realistic molecular dynamics simulations and Cahn-Hilliard phase-field simulations” (Ugis)
“Stability limits of liquid-infused surfaces and their effects on turbulent drag” (Johan)
“Droplet impact on asymmetric microstructures” (Susumu)
“New repulsive lift force between objects due variations of wall slip” (Shervin)
“Validation of Brinkman Equation for a simple shear driven flow over porous media” (Aidan)
See you virtually there!
Congratulations to Aidan Rinehart in our group for his first publication, which also is highlighted as “Editors’ suggestion”! Check it out if you are interested in lubrication forces, Janus particles, surface slippage, particle dynamics near interfaces.
Here is a brief popular science summary:
New repulsive force between objects
Surfaces in nature are rarely perfectly smooth but have physical, chemical and other defects. Our work has discovered a new hydrodynamic repulsive lift force that arises when surfaces with chemical contrasts or with varying textures come near contact. This lift force modifies the mobility of cells, colloids, bubbles, grains, and fibers traveling near walls and interfaces. Specifically, we demonstrate the spontaneous emergence of oscillations, transverse migration, spiral-like propulsive motion of a particle as it moves near a wall; these motions would not occur if the surfaces of the wall and the particle were perfectly homogenous. The physical mechanism behind the lift force is the breaking of the fluid pressure symmetry in the thin gap between two surfaces induced by a change of wall slip. Our study has implications for understanding how inhomogeneous biological interfaces interact with their environment; it also reveals a new method of patterning surfaces to reduce friction/wear or to influence self-assembly processes. Our work provides scaling estimates of the lift force induced by a change of wall slip for different configurations. This enables biologists, engineers, and physicists to predict the order of magnitude of the lift force, prior to performing experiments.
We have two exciting postdoctoral positions open in fundamental studies of turbulent transport near surfaces and complex materials! The projects can be tailored depending on the background of the candidate. See here for more general information. Contact Shervin if you are interested. We look forward to hearing from you!
Susumu has combined experiments, numerical simulations and scaling models to explain and describe a new hydrodynamic mechanism, which we call leaping, for the spreading of liquid drops on non-smooth and textured surfaces.
Similar to everyday life experience, where jumping and leaping to overcome obstacles increase the speed and efficiency of mobility, Susumu has shown that a liquid contact line may jump between texture posts and ridges and thus obtain speeds much larger than expected.
These insights improve our understanding of splashing, droplet impact, or in situations where time scales are imposed externally, such as wetting phenomena in the presence of vibrations. Moreover, our model helps in answering how asymmetric textured surfaces should be designed to direct the fast motion of liquids.
The article which of course is open access can be found here!
The animation below shows experiments (left) and numerical simulations (right) of a water drop spreading on skewed ridges.