Chine-shaped forebody effects on directional stability at high-alpha

Ravi, R.; Mason, William H.

doi:10.2514/3.46519

Cited by 7 publications

(3 citation statements)

References 4 publications

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“…The Figure 3 3D printer and additive manufacturing constants a and b in equation ( 1) control the maximum half width and half height of the cross section shape. When a = b, the shape becomes circular (Ravi and Mason, 1994). As the forebody is symmetric about the vertical centerline, a values for the right and left sides of the super-eclipse are the same.…”

Section: Forebody Design Parametersmentioning

confidence: 98%

Using additive manufactured parametric models for wind tunnel test-based aerodynamic shape optimization

Chung

Kim

Choi

2020

RPJ

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Purpose The purpose of this paper is to propose a new approach of using additively manufactured parametric models in the wind tunnel test-based aerodynamic shape optimization (ASO) framework and to present its applicability test results obtained from a realistic aircraft design problem. Design/methodology/approach For aircraft shape optimization, the following three methodologies were used. First, as a validation study, the possibility of using rapid prototyping (RP) model in the wind tunnel test was verified. Second, through the wind tunnel test-based ASO, the application and feasibility of the real fighter aircraft shape optimization were verified. A generic fighter configuration is parameterized to generate various test models using additive manufacturing. Wind tunnel tests are conducted to measure their stability criteria in high angle of attack (AOA). Finally, a computational fluid dynamics (CFD) study was performed and analysis procedures, costs and results compared to the wind tunnel test were compared and reviewed. Findings RP technology can significantly reduce the time and cost of generating parametric wind tunnel models and can open up new possibilities for wind tunnel tests to be used in the rigorous aerodynamic design loop. There was a slight difference between the results of the RP model and the metallic model because of rigidity and surface roughness. However, the tendency of the aerodynamic characteristics was very similarly predictable. Although there are limitations to obtaining precise aerodynamic data, it is a suitable method to be applied to comparative studies on various shapes with large geo-metric changes in the early phase of design. The CFD analysis indicates that the wind tunnel-based ASO using the RP model shows the efficiency corresponding to the CFD shape optimization. Research limitations/implications The RP parametric models may have various assembly error sources and rigidity problems. The proposed methodology may not be suitable for collecting the accurate aerodynamic database of a final design; rather, the methodology is more suitable to screen out many configurations having fairly large shape variation in the early stage of the design process. Practical implications The wind tunnel test-based ASO can replace or supplement CFD-based ASO. In areas where CFD accuracy is low, such as high AOA flight characteristics, RP model wind tunnel-based ASO can be a research method that can secure both efficiency and accuracy advantages, providing ten times more effective in terms of cost and time. The wind tunnel test is used to obtain aerodynamic data at the final stage of shape design. It can be extended to a comparative study of several shapes in the early design phase. This procedure can be applied for both industrial level and educational aircraft design activities. Originality/value This study is the application to be applied as a parametric study on the whole aircraft, rather than using the RP model applying a simple partial control surface or configuration change of a part of the wing. The possibility of using the RP model was confirmed by comparing and verifying each other in a medium-sized wind tunnel using a relatively large RP model and a metallic model. It was verified that it can be applied in the shape design process, not the shape verification in the traditional design procedure, and a comparison with the CFD method was also performed. With further development and validation efforts, the new design framework may become an industrial standard for future aircraft development.

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Section: Forebody Design Parametersmentioning

confidence: 98%

Using additive manufactured parametric models for wind tunnel test-based aerodynamic shape optimization

Chung

Kim

Choi

2020

RPJ

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“…This reduction in available yaw control occurs at approximately the same incidence as the yawing moment, required to maintain a coordinated roll about the velocity axis, substantially increases' 31 . The level of yawing moment required to coordinate a roll exceeds that available from found to be favourable with improved lateral-directional stability, due to a strong pair of forebody vortices originating at the fixed separation line of the chine* 5 - 8 '. Generating flow field asymmetries about such an aircraft's forebody poses new problems due to this fixed cross-flow separation point.…”

Section: Introductionmentioning

confidence: 94%

An experimental investigation into yaw control at high alpha on a chined forebody using slot blowing

Williams

Garry

1996

Aeronaut. j.

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Results are presented from low-speed windtunnel tests on an isolated generic chined forebody with pneumatic methods of yaw control at high alpha. Measurements of forces and moments were made on the forebody at angles of attack in the range 0° ≤ ɑ ≤ 60°. Slot blowing through the chine edge at various angles and upper surface tangential blowing have been compared, and optimum configurations have been identified. The effects of forebody cross-sectional shape have also been investigated and have been found to be highly critical in determining blowing effectiveness. Limited flowfield visualisation is also presented in order to gain some understanding of the flow field characteristics.

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“…[9][10][11][12][13][14][15][16][17][18][19][20] Ravi and Mason 9,10 studied the effects of the isolated fuselage on directional stability at high alpha and sideslip using both the Euler equations and Reynolds equations employing the Baldwin-Lomax turbulence model. They also developed an analytic model for systematically studying forebody aerodynamics for a family of forebody cross-sections.…”

mentioning

confidence: 99%

Aerodynamic Analysis of a Generic Fighter with a Chine Fuselage/Delta Wing Configuration Using Delayed Detached-Eddy Simulation

Jeans

McDaniel

Cummings

et al. 2008

26th AIAA Applied Aerodynamics Conference

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Chine-shaped forebody effects on directional stability at high-alpha

Cited by 7 publications

References 4 publications

Using additive manufactured parametric models for wind tunnel test-based aerodynamic shape optimization

Using additive manufactured parametric models for wind tunnel test-based aerodynamic shape optimization

An experimental investigation into yaw control at high alpha on a chined forebody using slot blowing

Aerodynamic Analysis of a Generic Fighter with a Chine Fuselage/Delta Wing Configuration Using Delayed Detached-Eddy Simulation

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