Separation Control by Self-Activated Movable Flaps

Schatz, Markus; Knacke, Thilo; Thiele, Frank; Meyer, Robert K.; Hage, W.; Bechert, D. W.

doi:10.2514/6.2004-1243

Cited by 29 publications

(29 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The experiment showed that the small flap (having a length of about 12% of the airfoil chord length) can increase lift by 10%, and a flap length of 22% resulted in an increase of 18% in the maximum lift. Similar results were found in other studies (Hafien et al 2013;Schatz et al 2004;Traub and Jaybush 2010;Mazellier and Kourta 2011).…”

Section: Introductionsupporting

confidence: 81%

Passive Separation Control on a Symmetric Airfoil via Elastic-Layer

Hafien¹,

Bourehla²,

Bouzaiane³

2016

JAFM

View full text Add to dashboard Cite

show abstract

Section: Introductionsupporting

confidence: 81%

Passive Separation Control on a Symmetric Airfoil via Elastic-Layer

Hafien¹,

Bourehla²,

Bouzaiane³

2016

JAFM

View full text Add to dashboard Cite

show abstract

“…Schatz et al [2,3] reported that the use of a passive flap near the trailing edge results in a lift increase at high angles of attack. The use of a passive flap is inspired by the feather structure of a bird on the upper side of the bird's wing [4,5].…”

Section: Introductionmentioning

confidence: 98%

“…1). Schatz et al [2,3] investigated the use of a passive flap to emulate this behavior. Their force measurements at Reynolds numbers above Re 1; 000; 000 showed an increase of lift of about 10%.…”

Section: Introductionmentioning

confidence: 98%

Lift Enhancement at Low Reynolds Numbers Using Self-Activated Movable Flaps

Schlüter

2010

Journal of Aircraft

View full text Add to dashboard Cite

“…Deflection of the upperwing coverts has the potential to limit the forwards extent of reversed flow, by forcing the separation point to rest at the base of each successive upperwing covert as it lifts (Schatz et al, 2004). Thus they may, in effect, act as a series of ratchet or valve-like features: deflections of single upperwing coverts, or groups thereof, might locally delay separation, which might in turn result in a significant global delay, increasing the effective maximum operating angle of attack of the wing (see Schatz et al, 2004). This is a fundamentally different hypothesis of function from previous suggestions that the upperwing coverts act as turbulators or vortex generators (Blick, 1976).…”

Section: What Aerodynamic Influence Might the Covert Feathers Have?mentioning

confidence: 99%

Automatic aeroelastic devices in the wings of a steppe eagleAquila nipalensis

Carruthers

Thomas

Taylor

2007

Journal of Experimental Biology

144

143

View full text Add to dashboard Cite

SUMMARY Here we analyse aeroelastic devices in the wings of a steppe eagle Aquila nipalensis during manoeuvres. Chaotic deflections of the upperwing coverts observed using video cameras carried by the bird (50 frames s–1) indicate trailing-edge separation but attached flow near the leading edge during flapping and gust response, and completely stalled flows upon landing. The underwing coverts deflect automatically along the leading edge at high angle of attack. We use high-speed digital video (500 frames s–1) to analyse these deflections in greater detail during perching sequences indoors and outdoors. Outdoor perching sequences usually follow a stereotyped three-phase sequence comprising a glide, pitch-up manoeuvre and deep stall. During deep stall, the spread-eagled bird has aerodynamics reminiscent of a cross-parachute. Deployment of the underwing coverts is closely phased with wing sweeping during the pitch-up manoeuvre,and is accompanied by alula protraction. Surprisingly, active alula protraction is preceded by passive peeling from its tip. Indoor flights follow a stereotyped flapping perching sequence, with deployment of the underwing coverts closely phased with alula protraction and the end of the downstroke. We propose that the underwing coverts operate as an automatic high-lift device, analogous to a Kruger flap. We suggest that the alula operates as a strake, promoting formation of a leading-edge vortex on the swept hand-wing when the arm-wing is completely stalled, and hypothesise that its active protraction is stimulated by its initial passive deflection. These aeroelastic devices appear to be used for flow control to enhance unsteady manoeuvres, and may also provide sensory feedback.

show abstract

Separation Control by Self-Activated Movable Flaps

Cited by 29 publications

References 3 publications

Passive Separation Control on a Symmetric Airfoil via Elastic-Layer

Passive Separation Control on a Symmetric Airfoil via Elastic-Layer

Lift Enhancement at Low Reynolds Numbers Using Self-Activated Movable Flaps

Automatic aeroelastic devices in the wings of a steppe eagleAquila nipalensis

Contact Info

Product

Resources

About