Vortex Generators AOE 4124 Dr. Mason March 26, 2004 Rich Stark Brian Squires Jessica Walker

Definition of Vortex Generators According to Clancy in “Aerodynamics” (Ref 1.) : According to Clancy in “Aerodynamics” (Ref 1.) : –Vortex generators are small, cambered, thin airfoils placed to introduce swirling motions that energize the boundary layer causing a delay in stall.

Common Applications External – Fuselage/Wing External – Fuselage/Wing –Upstream of flight control surfaces where BL attachment is critical Internal – Propulsion Internal – Propulsion –Prevents flow separation, excessive BL growth, and to reduce total pressure distortion of the flow ingested by the engine Wendt, B.J. and B.A. Reichert, “The Modelling of Symmetric Airfoil Vortex Generators.” AIAA Paper Ref. 2: Wendt, B.J. and B.A. Reichert, “The Modelling of Symmetric Airfoil Vortex Generators.” AIAA Paper

History of Vortex Generators First used in England (inventor unknown) First used in England (inventor unknown) Used first on Transport Jets and Bizjets Used first on Transport Jets and Bizjets Used as a “band-aid” for localized mach buffeting problems Used as a “band-aid” for localized mach buffeting problems First GA applications on Cessna 206 and Baron D-55 First GA applications on Cessna 206 and Baron D-55

How They Work Create strong tip vortices which feed high energy air from the external stream to mix with/replace the slower moving air in the boundary layer Create strong tip vortices which feed high energy air from the external stream to mix with/replace the slower moving air in the boundary layer Reduces the effects of adverse pressure gradients and prevents separation Reduces the effects of adverse pressure gradients and prevents separation Ref. 3

Flow Effects of VGs Ref. 4

Shed Vortex Structure Klausmeyer, Steven; Papadakis, Michael; and Lin, John, “A Flow Physics Study of Vortex Generators on a Multi-element Airfoil.” AIAA Paper Ref. 5 Klausmeyer, Steven; Papadakis, Michael; and Lin, John, “A Flow Physics Study of Vortex Generators on a Multi-element Airfoil.” AIAA Paper

VG Effect on C L at Various Angles of Attack Broadley, Ian and Garry, Kevin, “Effectiveness of Vortex Generator Position and Orientation on Highly Swept Wings.” AIAA Ref. 6 Broadley, Ian and Garry, Kevin, “Effectiveness of Vortex Generator Position and Orientation on Highly Swept Wings.” AIAA

Arrangement of VGs Usually located at the transition from laminar to turbulent flow Usually located at the transition from laminar to turbulent flow Typically 80% of boundary layer thickness Typically 80% of boundary layer thickness ws/ html ws/ html Ref. 4 ws/ html ws/ html

Various GA Aircraft Models Which Offer VG Kits BEECH Duke 60, A60, B60, Bonanza 33, 35, 36, 36TC CESSNA 120/140 Skywagon 180, , 310A-R, T310P-R 320D-F 335, 340, 340A 401, 401A, 401B 402, 402A, 402B, 402C 414, 414A 421, 421A, 421B, 421C 441 (Conquest II) BEECH Duke 60, A60, B60, Bonanza 33, 35, 36, 36TC CESSNA 120/140 Skywagon 180, , 310A-R, T310P-R 320D-F 335, 340, 340A 401, 401A, 401B 402, 402A, 402B, 402C 414, 414A 421, 421A, 421B, 421C 441 (Conquest II) deHAVILLAND Beaver Mk I deHAVILLAND Beaver Mk I Ref. 7

Various GA Aircraft Models Which Offer VG Kits (cont.) PIPER Navajo PA31-310, 325C/R Colemill Panther I & II Chieftan PA31-350, T1020 Seneca II/III/IV PA34 Super Cruiser PA12, PA14 Super Cub PA18 PIPER Navajo PA31-310, 325C/R Colemill Panther I & II Chieftan PA31-350, T1020 Seneca II/III/IV PA34 Super Cruiser PA12, PA14 Super Cub PA18 AGPLANES Ayres Thrush, Air Tractor, Cessna 188 AgWagon, Piper PA36 Brave, Dromader, Weatherly AGPLANES Ayres Thrush, Air Tractor, Cessna 188 AgWagon, Piper PA36 Brave, Dromader, Weatherly Ref. 7

Commercial Transport Aircraft with VGs Ref

Pros and Cons Pros: Pros: –Increases slope of lift curve –Increase in Gross Take-off Weight –Stall speed reduction (7-21%) –Improved handling qualities –Decrease tire and brake wear Cons: Cons: –Expensive –Makes debugging of the leading edge difficult –Possible source of vibration –Dual instruction and practice required for full effectiveness

More Pros Shorter take-offs and landings Shorter take-offs and landings Steeper climb-outs and approaches Steeper climb-outs and approaches Reduction of min control speed Reduction of min control speed No extra drag No extra drag No weight and balance change No weight and balance change No extra maintainence No extra maintainence

VGs are Everywhere! Ref. 8

Go Faster Strip Ref. 3

Head Mounted Vortex Generators Ref

References 1. Clancy, L.J. “Aerodynamics.” Halsted Press, Wendt, B.J. and B.A. Reichert, “The Modelling of Symmetric Airfoil Vortex Generators.” AIAA Paper Klausmeyer, Steven; Papadakis, Michael; and Lin, John, “A Flow Physics Study of Vortex Generators on a Multi-element Airfoil.” AIAA Paper Broadley, Ian and Garry, Kevin, “Effectiveness of Vortex Generator Position and Orientation on Highly Swept Wings.” AIAA  Animated vortex on title page taken from ref. 3