Mathematical model for two-dimensional multi-component airfoils in viscous flow

Stevens, W. A.; Goradia, S. H.; Braden, J. A.; Morgan, H. L.

doi:10.2514/6.1972-2

Cited by 63 publications

(19 citation statements)

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“…The unswept chord length of the new model is 1.829m, the sweep angle is 45°, and the angle of attack is set at -3°, the zero-lift angle. The theoretical inviscid pressure contour for this configuration, including the influence of the wind-tunnel walls, is computed using the MCARF code of Stevens et al (1971) and is shown with the wing contour in Figure 3. The code does not account for displacement thickness growth on either the model or the walls.…”

Section: General Philosophymentioning

confidence: 99%

Control of Transition in Swept-Wing Boundary Layers Using MEMS Devices as Distributed Roughness

Saric¹

1997

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REPORT DOCUMENTATION PAGEForm Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information SPONSOR/MONITOR'S ACRONYM(S) DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution is unlimited SPONSOR/MONITOR'S REPORT NUMBER(S)13. SUPPLEMENTARY NOTES 06414. ABSTRACT ~~ " Active flow control using MEMS-based microactuators holds tremendous promise for achieving laminar flow control and drag reduction for a wide class of aircraft. In order to achieve effective control it is necessary to have a complete understanding of the fundamental instability processes that apply to a particular boundary layer and to develop a sensor and actuator system that is capable of providing an appropriate control input to that boundary layer. In the present work, crossflow-dominated swept-wing boundary layers are the primary interest These boundary layers are known to undergo a highly nonlinear transition process that involves, in low-disturbance environments stationary waves of longitudinal vorticity. These stationary waves have to potential to be controlled or suppressed by an appropriate surface roughness configurations that could be provided by MEMS-based actuators. The work performed here consists of a parallel experimental and hardware development efforts. The breakdown phase of the crossflow instability is investigated in the experiments in an effort to determine an appropnate control input. A MEMS-based roughness actuator system is developed to provide controlled roughness inputs The results of the experimental phase conclusively demonstrate that the destabilization of a high-frequency secondary instability is responsible or breakdown The MEMS development effort did not produce a useful control device because of certain shortcomings in the present state of MEMS fabrication quality control and overall system integration. SUBJECT TERMS AbstractActive flow control using MEMS-based microactuators holds tremendous promise for achieving laminar flow control and drag reduction for a wide class of aircraft. In order to achieve effective control it is necessary to have a complete understanding of the fundamental instability processes that apply to a particular boundary layer and to develop a sensor and actuator system that is capable of providing an appropriate control input to that boundary layer. In the present work, crossflow-dominated swept-wing boundary layers are the primary interest. These boundary layers are known to undergo a highly nonlinear transition process that involves, in low-disturbance environments, stationary waves of longitudinal vorticity. ...

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Section: General Philosophymentioning

confidence: 99%

Control of Transition in Swept-Wing Boundary Layers Using MEMS Devices as Distributed Roughness

Saric¹

1997

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“…The second one is a panel method for the airfoil analysis problem as used in Ref. 5. Special, curved singularity elements with linear vorticity distribution have been developed in order to obtain good results near the trailing and leading edge and for thin airfoils.…”

Section: A Potential Flowmentioning

confidence: 99%

“…The computer program used here is similar to the program described in Ref. 5. The differences are described below.…”

Section: Mathematical Modelmentioning

confidence: 99%

Turbulent Airfoils for General Aviation

Eppler

1978

Journal of Aircraft

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Several new airfoils are presented which have short pieces of steep favorable pressure gradient followed by an early pressure recovery which is a compromise between the Stratford distribution and soft stall. The drag polars are computed by a mathematical model, which is briefly described. For comparison, NACA 65 2 -415 and NASA GA(W)-1 airfoils are evaluated using the same model; in this case the results are also compared with experimental drag polars.

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“…To obtain viscous-flow pressure distributions for comparison with experimental data, a computerized method, developed by the Lockheed Georgia Company for NASA (10), was used.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Low-Speed Aerodynamic Characteristics of a 13.1-PERCENT-THICK, High-Lift Airfoil

Sivier

Ormsbee

Awker

1974

SAE Technical Paper Series

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This paper is concerned with the experimental study of the low-speed, sectional characteristics of a high-lift airfoil and the comparison of those characteristics with the predictions of the theoretical methods used in the airfoil's design. The 13.1-percent-thick, UI-1720 airfoil was found to achieve the predicted maximum lift coefficient of nearly 2.0. No uppersurface, flow separation was found below the stall angle of attack of 16 degrees; it appeared that stall was due to an abrupt leading-edge flow separation.

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Mathematical model for two-dimensional multi-component airfoils in viscous flow

Cited by 63 publications

References 0 publications

Control of Transition in Swept-Wing Boundary Layers Using MEMS Devices as Distributed Roughness

Control of Transition in Swept-Wing Boundary Layers Using MEMS Devices as Distributed Roughness

Turbulent Airfoils for General Aviation

Low-Speed Aerodynamic Characteristics of a 13.1-PERCENT-THICK, High-Lift Airfoil

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