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VORTEX CONTROL BY THE SPANWISE SUCTION FLOW ON THE UPPER SURFACE OF delta wing

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Acta Mechanica Sinica 1999年第2期15卷 116-125页

作者：杨国伟陆夕云庄礼贤 Department of Modern Mechanics University of Science and Technology of ChinaHefei Anhui China 230026

The numerical investigation has been performed to explore the feasibility of vortex control by leading edge sucking excitation on a delta wing. The results reveal that the flow on the upper surface of the delta wing changes significantly in a wide range of the angle of attack. For the vortical flow at moderate angle of attack, the secondary and tertiary vortices are weakened or suppressed, and the total lift is almost unchanged. For the stalled flow at high angle of attack, the leading edge concentrated vortex is recovered, and the lift is enhanced with increasing suction rate. For the bluff-body flow at even high angles of attack, the lift can still be improved. The concentrated vortex disappears on the upper surface, and the load increment is nearly unchanged along the chordwise direction.

关键词： vortex control separation flow delta wing numerical simulation

Supersonic flow over a pitching delta wing using surface pressure measurements and numerical simulations

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Chinese Journal of Aeronautics 2018年第1期31卷 65-78页

作者： Mostafa HADIDOOLABI Hossein ANSARIAN Aerospace Engineering Department Malek Ashtar University of Technology

Experimental and numerical methods were applied to investigating high subsonic and supersonic flows over a 60°swept delta wing in fixed state and pitching oscillation. Static pressure coefficient distributions over the wing leeward surface and the hysteresis loops of pressure coefficient versus angle of attack at the sensor locations were obtained by wind tunnel tests. Similar results were obtained by numerical simulations which agreed well with the experiments. Flow structure around the wing was also demonstrated by the numerical simulation. Effects of Mach number and angle of attack on pressure distribution curves in static tests were investigated. Effects of various oscillation parameters including Mach number, mean angle of attack, pitching amplitude and frequency on hysteresis loops were investigated in dynamic tests and the associated physical mechanisms were discussed. Vortex breakdown phenomenon over the wing was identified at high angles of attack using the pressure coefficient curves and hysteresis loops, and its effects on the flow features were discussed.

关键词： delta wing Hysteresis loop Pitching oscillation Supersonic flow Vortex breakdown

Effects of sinusoidal leading edge on delta wing performance and mechanism

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Science China Technological Sciences 2013年第3期56卷 772-779页

作者： CHEN Huang PAN Chong WANG JinJun Fluid Mechanics Key Laboratory of Ministry of Education Beihang University

Lift and drag characteristics of delta wings with low swept angle and various sinusoidal leading edges(SLE) were investigated in a wind tunnel.Three amplitudes and three wavelengths of SLE were tested.It is revealed that,in comparison with the baseline case,when the leading-edge amplitude A?5%C(root chord length of a delta wing),the stall of the delta wing can be delayed without penalty on the maximum lift coefficient;meanwhile,the lift-to-drag ratio was kept nearly unchanged.These are beneficial to aircraft maneuverability and agility.Surface oil and hydrogen-bubble flow visualization experiments were further conducted to provide a general view of the underlying flow mechanism of SLE on delta wings.It was found that,for the flow over delta wing with SLE,vortices were generated from every crest of SLE,in contrast to the dual leading-edge vortex structure generated from the apex of the base wing.At high angle of attack,the breakdown of those vortices originating from the crests of SLE may provide additional turbulent kinetic energy to the flow,resulting in the increase of the flow reattachment region on the leeward side,therefore the stall can be delayed.

关键词： delta wing sinusoidal leading edge aerodynamic performance leading-edge vortex

Aerodynamic improvement of a delta wing in combination with leading edge flaps

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Theoretical & Applied Mechanics Letters 2017年第6期7卷 357-361页

作者： Tadateru Ishide Mao Itazawa National Institute of Technology Kisarazu College2-1 1-1 Kiyomidai-higashiKisarazu CityChiba292-O041Japan

Recently, various studies of micro air vehicle （MAV） and unmanned air vehicle （UAV） have been reported from wide range points of view. The aim of this study is to research the aerodynamic improvement of delta wing in low Reynold＇s number region to develop an applicative these air vehicle. As an attractive tool in delta wing, leading edge flap （LEF） is employed to directly modify the strength and structure of vortices originating from the separation point along the leading edge. Various configurations of LEF such as drooping apex flap and upward deflected flap are used in combination to enhance the aerodynamic characteristics in the delta wing. The fluid force measurement by six component toad ceil and particle image velocimetry （PIV） analysis are performed as the experimental method. The relations between the aerodynamic superiority and the vortex behavior around the models are demonstrated.

关键词： delta wing Leading edge flap PIV analysis Leading edge vortex Aerodynamic characteristics

Experimental Study on Aerodynamic Noise Radiated from delta wing

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Journal of Mechanics Engineering and Automation 2020年第6期10卷 161-169页

作者： H.Honda S.Ogawa K.Suzuki National Institute of Technology(KOSEN) Kure College2-2-11 AgaminamiKure CityHiroshima Prefecture 737-8506Japan Department of Mechanical Engineering National Institute of Technology(KOSEN)Kure College2-2-11 AgaminamiKure CityHiroshima Prefecture 737-8506Japan

Aerodynamic noise has been impairing the comfort of passengers in automobiles.Studies have shown that the aerodynamic noise is generated by the separation of the flow and the generation of the longitudinal vortex at the front pillar(A-pillar)and the door mirror.To remove the effects of the door mirror and extract the longitudinal vortex from A-pillar,studies employ the delta wing model.This research also employed the model and observed relations between the generated sound from the vortex at the A-pillar and the surface pressure fluctuation of the wing.The experiment was carried out in a wind tunnel of the Japan Aerospace Exploration Agency(JAXA)wind tunnel using the delta wing model.The radiated sound was measured using a far-field microphone to characterize the sound,and microphone array to conduct sound source exploration.Distribution of surface pressure fluctuation was measured using electret condenser microphones.Results showed that the radiated sound has a characteristic of dipole sound,and broadband sound from 1 kHz is radiated from the apex of the wing.Those indicate that sound generated from the apex of the delta wing was scattered at the surface of the delta wing,which follows the Lighthill-Curle theory.Surface pressure fluctuation with high fluctuation was distributed following the cone-like shape of the longitudinal vortex.Their peaks moved to the apex with the frequency increase.Coherence between far-field sound and surface pressure fluctuation was calculated.The point which is 70 mm inward from the apex showed higher value than those at the apex.As the diameter of the longitudinal vortex grows at the downstream,it is considered that a certain vortex scale radiates the most noise.

关键词： Aerodynamic noise longitudinal vortex delta wing experiment.

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1113 delta wing

汽车知识 2015年第6期 48-49页

Q:deltawingj是一个怎么样的设计公司,它设计了哪些车型?A:您好,2010年,日产与英国设计师Ben Bowlby、赛事企业家Don Panoz、前美国F1赛车手Dan Gurney与Duncan Dayton所组成的团队,便开始合作进行新世代赛车的deltawing Racing开发计划... 详细信息

Q:deltawingj是一个怎么样的设计公司,它设计了哪些车型?A:您好,2010年,日产与英国设计师Ben Bowlby、赛事企业家Don Panoz、前美国F1赛车手Dan Gurney与Duncan Dayton所组成的团队,便开始合作进行新世代赛车的deltawing Racing开发计划,并在2012年3月间发表了delta wing这款令世人大开眼界的赛车,并以此车参加了勒芒二十四小时耐力赛。尽管看似合作愉快,随后日产

关键词：二十四小时概念车 delta wing

Analysis of Shock and Vortex Breakdown Behavior in Unsteady Transonic Flow on A Slender delta wing

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Analysis of Shock and Vortex Breakdown Behavior in Unsteady ...

Aerodynamic Sound Radiated from Longitudinal and Transverse Vortex Systems Generated around the Leading Edge of delta wings

2010亚太航空航天技术研讨会

作者： Li Xile~* Yang Yong Jiao Jin National Key Laboratory of Science and Technology on Aerodynamic Design and Research Northwestern Polytechnical University Xi’an 710072 China

＜正＞A transonic flow around delta wing with sharp leading edge is simulated by detached eddy simulation（DES） method.The behavior of the complex shock waves in unsteady flow on the top surface of delta wing is analyzed at moderate and high angles of incidence.as well as the movement of the location of vortex breakdown induced by the shock.Numerical results indicate that three normal shock waves exist on the top surface of delta wing at both incidence angles.At angle of incidence ofα=18.5°,the rear/terminating shock propagates upstream to the sting tip from trailing edge periodically,the strength of shock becomes weaker as it moves forward.Ultimately,the rear/ terminating shock amalgamates with the normal shock wave at the sting tip.The location of vortex breakdown is close to the trailing edge. At angle of incidence ofα=23°,a second shock appears upstream of the sting tip,which moves analogically with the terminating shock for the case ofα=18.5°,it indicates that this shock is the rear/terminating shock having undergone an upstream shift with the increase of incidence.As while,the location of vortex breakdown induced by second shock moves periodically.

关键词： delta wing DES shock wave vortex breakdown periodic movement

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Open Journal of Fluid Dynamics 2016年第2期6卷 101-118页

作者： Shigeru Ogawa Jumpei Takeda Taiki Kawate Keita Yano Department of Mechanical Engineering National Institute of Technology Kure College Hiroshima Japan

Flow around the front pillar of an automobile is typical of a flow field with separated and reattached flow by a vortex system. It is known that the vortex system causes the greatest aerodynamic sound around a vehicle. The objective of the present study is to clarify the relationship between vortical structures and aerodynamic sound by the vortex system generated around the front pillar. The vortex system consists of the longitudinal and the transverse system. The characteristics of the longitudinal vortex system were investigated in comparison with the transverse one. Two vortex systems were reproduced by three-dimensional delta wings. The flow visualization experiment and the computational fluid dynamics (CFD) captured well the characteristics of the flow structure of the two vortex systems. These results showed that the longitudinal with the rotating axis along mean flow direction had cone-shaped configuration whereas the transverse with the rotating axis vertical to mean flow direction had elliptic one. Increasing the tip angles of the wings from 40 to 140 degrees, there first exists the longitudinal vortex system less than 110 degrees, with the transition region ranging from 110 to 120 degrees, and finally over 120 degrees the transverse appears. The characteristics of aerodynamic sound radiated from the two vortex systems were investigated in low Mach numbers, high Reynolds number turbulent flows in the lownoise wind tunnel. As a result, it was found that the aerodynamic sound radiated from both the longitudinal and the transverse vortex system was proportional to the fifth from sixth power of mean flow velocity, and that the longitudinal vortex generated the aerodynamic sound larger than the transverse.

关键词： Aerodynamic Noise delta wing Longitudinal Vortex Transverse Vortex CFD

A STUDY OF UNSTEADY STRUCTURES IN VORTEX BREAKDOWN OVER delta wingS

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A STUDY OF UNSTEADY STRUCTURES IN VORTEX BREAKDOWN OVER DELT...