Experience in the use of computational aerodynamics to predict store release characteristics

Cenko, A.

doi:10.1016/s0376-0421(01)00013-6

Cited by 15 publications

(7 citation statements)

References 23 publications

(6 reference statements)

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“…Beyond the present studies into interference and redesign of the sting, an investigation of the sting influence on weapons bay cavity effects is planned, and this would involve a high-fidelity match between complex wind tunnel models and corresponding CFD as is increasingly called for by some sectors of the store release research community 12 . The continued synergy between the two techniques, hand-in-hand from the beginning of any such study, will greatly enhance the quality of the output, and the depth of understanding of the flowfield and correlation discrepancies.…”

Section: Discussionmentioning

confidence: 99%

Aspects of sting interference for transonic store release wind tunnel testing

Doig

Bogdan²,

Snyder

et al. 2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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In order to maximize stealth potential and aerodynamic performance, internal weapons bays are increasingly common on military aircraft and are particularly key for coming generations of UCAVs. Wind tunnel testing of store release problems therefore generally requires the ordinance to be mounted to its own sting strut from underneath, such that it can be placed in, and "dropped" from, the bay. Interference from this strut can disrupt the forces and moments obtained, and thus an investigation has been conducted into the extent of this interference, looking at the sting arm length and the geometry of the connection to the store as variables over a sweep of angles of attack. Original small-scale transonic wind tunnel testing was conducted, against which a numerical approach was validated, allowing investigations to conclude that the specific geometry of the sting at the attachment point had a much greater influence than any other geometric parameters, with non-linear interference observed through a range of angles of incidence.

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Section: Discussionmentioning

confidence: 99%

Aspects of sting interference for transonic store release wind tunnel testing

Doig

Bogdan²,

Snyder

et al. 2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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“…It is now relatively common for computational fluid dynamics (CFD) work, particularly using Reynolds-Averaged Navier-Stokes (RANS) modelling, to be involved in the process to both predict design problems in advance of physical testing and, increasingly, to plan and help interpret the tunnel data itself before scaling up to real-world Reynolds numbers to anticipate further issues. [1][2][3][4][5] Mounting an aircraft tunnel model to one sting, and the store from the rear to another, is not applicable for weapons bay work where the store is originally in the cavity when ejected, before crossing the highly turbulent shear layer and proceeding to clear the vicinity of the aircraft. An additional strut arm connecting to the middle of the store is one standard design approach (a very short rear sting and strut could interfere much more with the cavity flow), whereby the sting itself can be far from the store, reducing interference.…”

Section: Introductionmentioning

confidence: 99%

“…1 It would be markedly more preferable to be able to trust results obtained with the strut knowing that behaviour would not change non-linearly or suddenly across the angle of attack, roll or yaw ranges.…”

Section: Introductionmentioning

confidence: 99%

“…It is now relatively common for computational fluid dynamics (CFD) work, particularly using Reynolds-Averaged Navier–Stokes (RANS) modelling, to be involved in the process to both predict design problems in advance of physical testing and, increasingly, to plan and help interpret the tunnel data itself before scaling up to real-world Reynolds numbers to anticipate further issues. 1–5…”

Section: Introductionmentioning

confidence: 99%

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Reducing transonic wind tunnel sting interference effects for concealed store release testing

Doig

Bogdan

Kabir

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part G:

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Internal weapons bays are becoming increasingly common on aircraft for reasons of stealth and aerodynamic performance, and will be even more prevalent on coming generations of unmanned combat aerial vehicles (UCAVs). Wind tunnel testing of store releases to assess forces and moments for safety and clearance must be conducted with a store mounted to an angled strut rather than a conventional rear sting, to allow the full range of motion as the store ''drops'' from inside the aircraft. Interference from this strut can disrupt the flowfields and thus the reliability of moments obtained, and therefore an investigation was conducted to quantify the potential extent of discrepancies; original small-scale transonic wind tunnel testing was undertaken in a limited program which was supported by extensive numerical work. It was concluded that the precise geometry of the strut/store interface was of critical importance, with a typical design producing non-linear interference at high angles of attack. A simple improved design is proposed -making use of a blended interface and a more appropriate supercritical aerofoil strut cross section -yielding marked improvements in force and moment predictions.

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“…또한 자유낙하시험을 통해 얻은 결과는 scaling 방법을 적용하여 정확한 궤적 자료를 만들 수 있는 장 점을 가지고 있다 [3] . 이는 실제 항공기의 비행조건이 저 아음속 영역에 속 하므로 압축성 효과가 거의 발생하지 않으며 [7] , 저속 에서 무장의 항력이 분리 궤적에 미치는 영향은 무장 의 관성력에 의한 영향에 비해 비교적 적기 때문에 점성의 효과는 무시할 수 있는 것으로 가정하였다 [8] .…”

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An Experimental Study on Aircraft Internal Store Separation Characteristics

An¹,

Cho²,

Kim³

et al. 2017

Journal of the Korea Institute of Military Science and Technolo

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This study investigates store separation characteristics of an unmanned aerial vehicle having generic stealth configuration over unsteady flow of an internal bay. Free-drop wind tunnel tests are conducted to simulate bomb releases from an internal weapons bay while high-speed camera images are taken. The images are analyzed to examine the effects of flow velocity, angle of attack, flap deflection and the ejector force application on the store separation trajectories. For the free-drop wind tunnel tests, Froude Scaling is applied to match the dynamic similarity for the bomb model, and the ejector force is simulated by using small pneumatic cylinders. The results indicate that the test bomb model safely separates from the internal bay at the given test conditions and configurations. It is also observed that the effects of the flow velocity and ejector force application have greater impacts on the separation trajectories than those of angle of attack and flap deflection.

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Experience in the use of computational aerodynamics to predict store release characteristics

Cited by 15 publications

References 23 publications

Aspects of sting interference for transonic store release wind tunnel testing

Aspects of sting interference for transonic store release wind tunnel testing

Reducing transonic wind tunnel sting interference effects for concealed store release testing

An Experimental Study on Aircraft Internal Store Separation Characteristics

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