22 September 2009

New Publication from Oxford Group

In a new paper published in Science last week the Oxford group of animal flight, headed by Adrian Thomas, shows how important it is for a locust to have appropriate camber and wing twist to maintain the high performance achieved by insect wings. The way they do it is by using a CFD (computational Fluid Dynamics) model, and in a stepwise manner remove the camber and twist exhibited by the real locust. Before trusting the model output, the CFD model was validated against real data using smoke flow visualization and PIV measurements obtained from locusts tethered in the wind tunnel. In accompanying podcast Adrian explain certain problems they had in modeling the upstroke of the hind wings, so go an listen also for that.

15 September 2009

Final symposium tally

Abstract submission has closed for SICB's 2010 meeting, where we (Isabelle Bisson, Martin Wikelski, and I) will be holding our Integrative Migration Biology symposium. The way SICB organizes the meetings, the 13 symposium speakers (including Anders, Susanne and myself) are set, but people can apply to give a presentation in a coordinated session. The official numbers are in, and our symposium attracted more coordinated session speakers (24) than any other symposium this year! I can't wait to meet and talk with everyone who's coming; it sounds like there will be some great presentations.

You can still register for the meeting if you haven't already; it should be a lot of fun--and there are plenty of biomechanics talks for those of you who are less interested in migration than I am!

New Lab intern: Roel Vleugels

During the autumn 2009 Roel Vleugels, a student of aeronautical engineering at Delft University, is visiting our lab as part of his master program. Roel is going to adapt our aerodynamic balance for precise measurements of aerodynamic forces on different wings, such as flat plates and the Eppler 387. He will also make measurements on the drag of a swift look-alike model bird body. We welcome Roel to the group and hopes he gets a great time while here!

01 September 2009

New Fridge for the Wind tunnel

A new fridge was delivered today, 1 September 2009, to be used for storing animal food for wind tunnel birds and bats. The fridge has a constant temperature facility, meaning it has a fan that mixes the air inside the fridge. The old fridge was broken since many years and in the interim a constant temperature box has been used, which accommodates fridge-like temperatures but is otherwise not large enough. The recent problems with the large generic cold rooms in the Ecology building, with measurable water depth on floor and mold infestations, made this acquisition a necessary step in order to be able to keep high quality mealworms, crickets, honey, and nectar plus at optimal conditions. The picture shows happy Florian Muijres and Melissa Bowlin during the installation procedure of the new fridge.

Aerodynamic wake behind a flying bat

Here is a nice instructive video of the aerodynamic wake behind a flying bat. The bat species is Glossophaga soricina, and it has a forward flight speed of 4 m/s.

In the movie you see the flying bat from behind. The right side of the movie shows the right half of the bat body and its right wing, while the left side of the movie shows the wake generated by the flapping left wing. This wake is calculated using our DPIV system. The colors in it are vorticity strength while the black arrows are the in-plane air velocity vectors.

The movie is slowed down 10 times and it is looped 5 times.