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Tuesday, August 4, 2020 | History

3 edition of Controlled vortical flow on delta wings through unsteady leading edge blowing found in the catalog.

Controlled vortical flow on delta wings through unsteady leading edge blowing

Controlled vortical flow on delta wings through unsteady leading edge blowing

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  • 16 Currently reading

Published by Stanford University, Dept. of Aeronautics and Astronautics, Joint Institute for Aeronautics and Acoustics in Stanford, CA .
Written in English

    Subjects:
  • Delta wing airplanes.,
  • Vortex-motion.

  • Edition Notes

    Statementby K.T. Lee and Leonard Roberts.
    SeriesJIAA TR -- 97., NASA-CR -- 186267., NASA contractor report -- NASA CR-186267., JIAA TR -- 97.
    ContributionsRoberts, Leonard., United States. National Aeronautics and Space Administration.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL15290437M

    To evaluate the feasibility of this technique, surface luminescent dye visualizations on a 65 deg delta wing and a 76/40 deg double-delta wing are conducted in a water tunnel. The extracted skin friction topology on the delta wings and the velocity fields obtained by using particle image velocimetry (PIV) are   At high angles of attack the leeward flow field for slender delta wings is dominated by a highly organized vortical flow structure emanating from the sharp leading edges. The vortex sheet shed from the leading edge rolls up into a pair of strong vortices. As the angle of attack is increased, these leading edge vortices interact with each other

    Summary. Here, we present a protocol to observe unsteady vortical flows over a delta wing using a modified smoke flow visualization technique and investigate the mechanism responsible for the oscillations of the leading-edge vortex breakdown ://   large leading-edge vorticity, possibly stabilized by spanwise flow through the core of the leading edge vortex is well established ([81], [23], [99], [18]). Rotational velocity is also well known to enhance lift if properly timed ([88], [89]). Wake capture means

      Vortical Flow over a Supersonic Delta Wing J Through Porous Leading Edge J Unsteady Flow Phenomena over Delta Wings at High Angle of Attack J Simple Numerical Criterion for Vortex Break-down J Improving the Efficiency of Aerodynamic Shape Review of Unsteady Vortex Flows Over Delta Wings. Ismet Gursul; APA Vortex Breakdown Over Slender Wings: Part I - Experimental & Analytical Efforts (Invited) • Wednesday, 25 June • hrs Visualization and Wake Survey of the Vortical Flow over a Delta Wing with the Leading Edge Extension. APA Vortex/Vortical Flow


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Controlled vortical flow on delta wings through unsteady leading edge blowing Download PDF EPUB FB2

The vortical flow over a delta wing contributes an important part of the lift--the so called nonlinear lift. Controlling this vortical flow with its favorable influence would enhance aircraft maneuverability at high angle of attack.

Several previous studies have shown that control of the vortical flow field is possible through the use of blowing :// L/abstract. Get this from a library. Controlled vortical flow on delta wings through unsteady leading edge blowing.

[K T Lee; Leonard Roberts; United States. National Aeronautics and Space Administration.]   Controlled Vortical Flow on Delta Wings Through Unsteady Leading Edge Blowing By K. Lee and Leonard Roberts Stanford University Department of Aeronautics and Astronautics Stanford, CA January (,NASA-CR-Id_Z&7) LPNTR!_LL_r.

VCJPTICAL FLC_W ON _ELTA WI_,I{,F THP,OtJL_H UNSTEADY LEAOlN5 £_GE BLGV/I_JG (Stanford Univ.) 1_4,q CSCL The effect of unsteady blowing through the leading edge on the flow structure over a 45 deg swept delta wing in relation to the steady blowing is experimentally studied in a low-speed wind tunnel An analysis is presented on the compressible inviscid vortex flow over three delta wings with sharp leading edges with leading edge sweep angles *&#, 70, and 76 deg using numerical solutions   Instances of open loop flow control strategies employed in nature are given, as are examples of open and closed loop flow control of separated flows.

These include dynamic stall control on rotorcraft, leading edge suction and blowing on delta wings, and the use of adaptive control algorithms such as neural networks and genetic :// The response of these vortices during maneuvering flight is the dominant aspect of the flow.

The leading edge vortices form due to flow separation from the leading edges of the wing (which are generally sharp on delta wings), with the resultant shear layer rolling up due to a span- wise pressure gradient along the surface of the :// Lee, K.T.

Controlled Vortical Flow on Delta Wings Through Unsteady Leading-Edge Blowing, PhD Thesis, Stanford University, August Parmenter, K. and Rockwell, D.

Transient response of leading-edge vortices to localised suction, AIAA J, June28, (6), pp –   The delta wing model used in our experiment is a degree-sweep delta wing configuration made from aluminum, as shown in Fig. 1(b).

The wing model has a chord length of c = mm, a thickness of t = mm, a 45 degree beveled sharp leading edge (LE), and a square trailing edge (TE).A constant chord aluminum LEVF is placed at the leading edge of the delta wing with a chord of breakdown on delta wings can be controlled by various blowing techniques [14–22].

For instance, Mitchell et al. [23] showed that asymmetric blowing along the surface on the leeward side of a delta wing near the apex affects ideofthewingwithblowing, vortex breakdown was The decreasing-blowing pattern compared to uniform blowing seems to be more efficient on the overall flow structure, indicating that control through leading edge near the apex region is more   This opens the possibility of utilizing novel concepts for the control and stability of delta wings by deliberately manipulating the vortical flow at the leading edge.

Such approaches can be particularly useful at greater angles of attack when the effect of classical control surfaces at the trailing edge becomes ineffective because the control The effects of the sideslip angle on the vortical flow of a delta wing with the leading edge extension(LEX) at high incidence was investigated through the pressure measurement of the wing upper Flow Induced Unsteady Loads and the Impact on Military Applications [RTO-MP-AVT],pp.

more BibTeX; Moelyadi, M.A.; Jiang, L.; Breitsamter, C.: Investigation of Steady and Unsteady Flow Behaviours of TSTO Space Transport System. AIAA CIRA International space Planes and Hypersonic Systems and Technologies Conference, Flow visualization was used to study the effects of a vectored trailing edge jet on the leading edge vortex breakdown of a 65 delta wing.

The experimental results indicated that there is little Kandil, O.A. and Salman, A.A. Effects of leading-edge flap oscillation on unsteady delta wing flow and rock control, AIAA PaperMagness, C ; Robinson, O. and Rockwell, D. Control of leadingedge vortices on a delta :// With unsteady jet blowing at the leading edge additional momentum is created leading to a reattachment of the flow at the wing surface thus increasing the lift significantly.

The investigated flow control method can be applied for extending the flight envelope, enhancing maneuvering capability and flight ://   Flow control can significantly improve the aerodynamic performances of delta wings. Yet, despite numerous studies of vortex control by leading-edge blowing still little research is focused on the post-stall regime and further consideration of the shear-layer reattachment through flow control is :// Following the identification and confirmation of the substructures of the leading-edge vortex (LEV) system on flapping wings, it is apparent that the actual LEV structures could be more complex than had been estimated in previous investigations.

In this experimental study, we reveal for the first time the detailed three-dimensional (3-D) flow structures and evolution of the LEVs on a flapping 1.

Introduction. Leading-edge vortices (LEVs) play an important role in unsteady aerodynamics. They increase the achievable lift beyond static conditions through the delayed stall effect [1,2].In biological flapping flight or technical applications (e.g. micro air vehicles (MAVs)), these effects are used to generate the necessary lift, which, according to Jones et al.

[], would be insufficient. control of unsteady turbulent boundary layers and separated flows, and active control of the vortical flow over delta wings using leading-edge blowing. r 20 DISTRIBUTION AVAILABILITY OF ABSTRACT ABSTRACT SECURITY CLASSIFICATION 0 UNCLASSIFIEDUNLIMITED 9(SAME AS RPT.

E DTIC USERS lnc jsi fil'J "2'a NA^MP ://  Analysis of Vortical Flow Field in a Propeller Fan by LDV Measurements and LES—Part II: Unsteady Nature of Vortical Flow Structures Due to Tip Vortex Breakdown Trailing-edge jet control of leading-edge vortices of a delta wing.

Vortex breakdown over delta wings in unsteady free stream. ISMET GURSUL and The active flow control actuators are a pair of downward blowing slot jets located at the trailing edge of the model as shown in Fig. 2. The flow rates to the left and right side actuators is controlled by the voltage to a pair of Clippard proportional valves (EV-P).

The slot jet exits are have a width of mm and a length of 30 ://