2026-10-11T22:37:11Z https://api.figshare.com/v2/oai

oai:figshare.com:article/34036035 2026-09-30T17:43:02Z category_1 category_915 category_21 category_272 category_39 category_734 category_106 portal_5 item_type_1 month_year_09_2026

<p>Nightjar vortex wake displays double tip vortices and upstroke thrust.</p> L. Christoffer Johansson (8029388) Gabriel Norevik (589846) Sonja Friman (25145400) Anders Hedenström (150704) Biophysics Physical Sciences not elsewhere classified Biotechnology Environmental Sciences not elsewhere classified Ecology Biological Sciences not elsewhere classified Science Policy using wake visualization reduced span efficiency phenomenon may stem multiple costly behaviors may apply generally kinematic analysis suggests characteristic previously attributed caprimulgus europaeus </ cruising speed efficiency reflects complex tradeoffs european nightjar (< also uses slow div >< p cruising flight — cruising speeds tradeoffs seen slow flight nightjar ’ hummingbirds — wing shape wing folding wind tunnel results highlight particularly interesting makes studies generating lift flight speeds flight performance flapping flight feeding ecology faster speeds existing paradigm ecological demands distance migrant animals engaged aerodynamic mechanisms aerodynamic measurements <p>Wake vortices shown as iso-surfaces of total vorticity [s⁻¹] (iso value = 100), color-coded by downwash velocity (<i>v</i>_z) of a sample sequence of a European nightjar flying at 9 m/s. Note the double tip vortices during the downstroke (upper inlet) and the reversed vortices at the outer wing during the upstroke (lower inlet). The inlets show in-plane velocity vectors on a background of the streamwise vorticity with blue showing clockwise rotation and yellow/red counterclockwise rotation. Vectors are not scaled the same in the two inlets but are scaled to facilitate interpretation of the flow. Units on the 3D-axes are in m.</p> 2026-09-30T18:03:55Z Image Figure 10.1371/journal.pbio.3004023.g001 https://figshare.com/articles/figure/_p_Nightjar_vortex_wake_displays_double_tip_vortices_and_upstroke_thrust_p_/34036035 CC BY 4.0