Catch a glimpse of a fish's body shape, and you can often guess how speedy it is. Tuna and mackerel look as if they should outpace frilly reef fish and eels. But how have all of these diverse body shapes evolved? Have fish bodies been shaped by the hydrodynamics of their environment or did they evolve for other reasons?
Turning to computational fish for answers, professor of Civil Engineering Fotis Sotiropoulos, along with postdoctoral researcher Iman Borazjani, from the university’s St. Anthony Falls Laboratory decided to race hybrid and realistic fish in a massive parallel computer cluster to find out what influence the aquatic environment has had on fish shapes and swimming techniques.
But building the computational fish was far from straightforward. ”We started this work over five years ago,“ says Sotiropoulos. "It was a challenge because we had never simulated anything living before."
Borazjani explains that the hydrodynamic forces exerted on swimmers vary enormously depending on their size and speed. Knowing that mackerel and eels swimming in water generate and thus experience different hydrodynamic environments, the duo simulated these different environments by varying tail beat frequencies and fluid viscosity (syrupiness).
Building two computational mackerels (one that beat its tail like a mackerel and a second that wriggled like an eel) and two eels (one that wriggled and another that beat its tail like a mackerel), the engineers set the fish racing from standing starts and noted how they performed.
The results showed clearly that all fish swam more efficiently if they had the body form or swimming style appropriate to the speeds at which they swam. For example, a lamprey that needed to swim faster could gain efficiency—which for a real fish would mean tiring less quickly—if it changed its shape or swimming style to mimic a mackerel. And a mackerel that had to move slowly would be more efficient if it could change shape or swimming style to mimic a lamprey. This is evidence that a fish’s optimal range of swimming speeds generates hydrodynamic forces that influence the shape and swimming style it will evolve.
“From these experiments, we can deduce that real mackerel and eel's swimming styles are perfectly adapted to the hydrodynamic environments that they inhabit," says Sotiropoulos. The method could be adapted to study how a fluid environment molds the evolution of other organisms and to design robots that would swim at different speeds or in water of different viscosities, the researchers say.
The full article can be found on the Journal of Experimental Biology Web site: http://bit.ly/b2ZqeY
More information about professor Sotiropoulos’ research at the St. Anthony Falls Laboratory can be found at www.safl.umn.edu.
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy