Show archive
Winning Video Contest APS-DFD “Gallery of fluid motion”
The gallery of fluid motion is an international annual contest in which videos and images compete for the aesthetic and science of contemporary fluid mechanics, and it is given during the American Physics Society conference on Fluid Dynamics. Our winning video entry is called “The Yarning Droplet” by Carola Seyfert (PhD) and Alvaro Marin (Assoc. Prof.). Music by Rodrigo Ezeta (PoF alumnus). This is the 3rd gallery of fluid motion winning entry for Alvaro Marin and the 11th for the Physics of Fluids cluster at the University of Twente.
Aurel Stodola medal awarded to Professor Detlef Lohse
The Aurel Stodola Lecture Series commemorates the personality and seminal contributions of Prof. Aurel Stodola in the early 20th century whose work on applied thermodynamics has guided many engineers and engineering developments worldwide. The Department of Mechanical and Process Engineering (D-MAVT) elected Prof. Dr. Detlef Lohse as the 2021 Laureate of the Aurel Stodola Lecture.
Microswimmers May Shepherd Large Liquid Volumes
Microswimmers can serve as cargo carriers that move deep inside complex flow networks. When a school collectively entrains the surrounding fluid, their transport capacity can be enhanced. This effect is quantified with good agreement between experiments with self-propelled droplets and a confined Brinkman squirmer model. The volume of liquid entrained can be much larger than the droplet itself, amplifying the effective cargo capacity over an order of magnitude, even for dilute schools. Hence, biological and engineered swimmers can efficiently transport materials into confined environments.
Windbreaks May Improve Wind Farm Power
Cost-effective ways to produce more renewable energy are critical in the fight against climate change. New simulations suggest that windbreaks—barriers, such as walls or rows of trees—can improve the power generation of wind farms by as much as 10% [1]. Previous work suggested that windbreaks can help individual wind turbines but that they are counterproductive for very large wind farms. The new work is the first simulation of a realistic wind farm with windbreaks. The researchers involved hope that their work will lead to improved efficiency in real wind farms.
Wind turbines unexpectedly more productive behind hill
If someone asked you to name the ideal place to build a wind turbine, chances are your first answer would not be “behind a hill”. Yet researchers from the University of Twente have discovered that in some cases wind turbines can actually produce more energy in that position than in a wide, open landscape. In an article published in the leading scientific journal Renewable Energy, Dr Luoqin Liu and Dr Richard Stevens (Faculty of Science and Technology) show in a series of simulations that wind turbines behind hills can generate up to 24% more energy.
Exhaled Droplets Grow in Size on Cool Days
The COVID-19 pandemic has focused attention on the respiratory droplets produced by breathing, coughing, and singing. Numerical simulations of a cough now show [1] that in cooler, more humid air, these droplets first grow before evaporating and shrinking—they don’t continuously evaporate, as previous research has suggested. The growth occurs when warm, humid breath interacts with colder air, producing a plume of water-vapor-saturated air—an effect that leads to the familiar “frosty” breath on cold days. The enlargement of cough droplets inside this plume causes them to survive longer than they do at higher temperatures, potentially allowing an infected person to spread an airborne disease to people located farther away.
Overdracht van Corona via Aerosolen, stand van de wetenschap na een jaar van pandemie
In een recent webinar van de Koninklijke Akademie van Wetenschappen (KNAW) kwamen sprekers uit de verschillende relevante disciplines bijeen om de huidige inzichten in de verspreiding van het Coronavirus, via aerosolen, te bespreken. Na de bijeenkomst hebben wetenschappers van de Universiteit van Cambridge, de Universiteit van Amsterdam en de Universiteit Twente, onder wie UT-vloeistoffysicus prof Detlef Lohse, een informatiedocument opgesteld met de nieuwste wetenschappelijke inzichten. Het document ‘Aerosolen, ventilatie en COVID19’ is nu online beschikbaar.
Windparken profiteren van sterke stroming in lagere atmosfeer
Krachtige luchtstromingen in de lagere atmosfeer, de zogenaamde ‘low-level jets’ hebben invloed op de prestaties van windmolenparken. De hoogte waarop dit effect plaatsvindt, maakt het verschil: stroomt het op het niveau van de windturbine, erboven of eronder? Die hoogte bepaalt of alle molens in het park van de stroming kunnen profiteren, of alleen de turbines op de eerste rij. Dit laten onderzoekers van de Universiteit Twente zien in het Journal of Renewable and Sustainable Energy.
'Mayonnaise' shows extreme behaviour in turbulent flow
When water and oil form an emulsion inside a strong turbulent flow, this emulsion consists of either water-in-oil droplets or oil-in-water droplets. The turning point between these two is spectacular, researchers of the University of Twente now show: it can make a difference of liquid friction of a factor six. The size of the droplets changes equally fast. This effect may have consequences for the transport of oil or nutrients. The paper, informally already known as ‘the mayonnaise paper’ is in Physical Review Letters and highlighted as an ‘Editor’s suggestion’.
Trillende nanodruppels kunnen doordringen in tumor
Minuscule druppels naar een tumor sturen en die ter plekke met een gefocusseerde geluidbundel laten verdampen: het kan een manier zijn om de tumor te beschadigen of lokaal medicijnen af te leveren. Onderzoekers van de Universiteit Twente laten nu een nieuw fenomeen zien dat de druppelverdamping in gang zet: het gebeurt precies bij de akoestische resonantiefrequentie en zorgt voor een snelle en efficiënte verlaging van de druk in de druppel, tot ónder de drempelwaarde voor verdamping. De onderzoekers publiceren erover in Physical Review Letters.

The 10th Complex Motion in Fluids 2022
Max Planck Gesellschaft
Centre for Scientific Computing