BEGIN:VCALENDAR

VERSION:2.0

PRODID:-//wp-events-plugin.com//6.6.4.4//EN

TZID:Asia/Jerusalem

X-WR-TIMEZONE:Asia/Jerusalem
BEGIN:VEVENT

UID:0-489@aerospace.technion.ac.il

DTSTART;TZID=Asia/Jerusalem:20160217T163000

DTEND;TZID=Asia/Jerusalem:20160217T173000

DTSTAMP:20230603T191958Z

URL:https://aerospace.technion.ac.il/events/on-the-annual-cycle-of-a-hover
 ing-hummingbird-an-aerodynamic-and-fluid-mechanics-perspective/

SUMMARY:On the Annual Cycle of a Hovering Hummingbird: An Aerodynamic and F
 luid Mechanics Perspective
DESCRIPTION:Lecturer:Yonathan Achache\n Faculty:Technion Autonomous Systems
  Program\n Institute:Technion – Israel Institute of Technology\n Locatio
 n:Classroom 165\, ground floor\, Library\, Aerospace Eng.\n Zoom: \n Abstr
 act: \n Details: \n The diverse hummingbird family (Trochilidae) has uniqu
 e adaptations for nectarivory\, among which is the ability to sustain hove
 r feeding. As hummingbirds mostly feed while hovering\, it is crucial to m
 aintain this ability throughout the annual cycle and especially during fli
 ght feather moult\, when feathers are missing from the wing structure. The
  presented research will focus on the wing of Calypte anna\, a common humm
 ingbird species in western North America\, which consists of ten primary f
 light feathers whose deficit during moult may strongly affect wing aerodyn
 amics.\nThe goal of this work is to quantify the aerodynamic characteristi
 cs and flow mechanisms during the wing's annual cycle. Birds usually moult
  their feathers in a deterministic sequence that may have aerodynamic\, ph
 ysiological and behavioural ramifications. Unsteady aerodynamic loads and 
 flow field measurements are correlated over a complete dynamically scaled 
 Anna's wing model and several wing geometries that follow the feather repl
 acement sequence characterising a natural moult cycle. Using dynamic simil
 arity\, wing models were tested in water-glycerin solutions at biologicall
 y relevant Reynolds numbers and various angles of attack.\nResults were ta
 ken over a model of a complete wing in order to depict the baseline aerody
 namic characteristics and flow mechanisms involved. Unsteady vorticity con
 centration evolved from the wing's leading-edge differs in both size and e
 xtent from attached vorticity structures typically found over insects\, wh
 ich themselves operate at Reynolds numbers which are two orders of magnitu
 de smaller than those of hummingbirds. Estimation of the complete wing per
 formance suggests it yields comparable lift coefficients and higher lift-t
 o-drag ratios to those found over insects.\nMeasurements taken at several 
 moult stages suggests that the wing's integrity in the medial and leading-
 edge region affects the flow field considerably such that lift production 
 drops disproportionately higher in relation to the loss of wing area\, whi
 ch explains why the leading feathers of the wing are essential to obtain h
 igh lift capacity during hovering. Furthermore\, specific-power analysis s
 uggests a distinct link to behavioural repertoire and mass reduction chara
 cterising moulting hummingbirds.
CATEGORIES:Seminars
LOCATION:Classroom 165\, ground floor\, Library\, Aerospace Eng.

END:VEVENT

BEGIN:VTIMEZONE

TZID:Asia/Jerusalem

X-LIC-LOCATION:Asia/Jerusalem

BEGIN:STANDARD

DTSTART:20151025T010000

TZOFFSETFROM:+0300

TZOFFSETTO:+0200

TZNAME:IST

END:STANDARD

END:VTIMEZONE
END:VCALENDAR