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flow separation control on swept wing with nanosecond pulse driven DBD plasma actuators

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Chinese Journal of Aeronautics 2015年第2期28卷 368-376页

作者： Zhao Guangyin Li Yinghong Liang Hua Han Menghu Wu Yun Science and Technology on Plasma Dynamics Laboratory Air Force Engineering University

A 15° swept wing with dielectric barrier discharge plasma actuator is designed. Experimental study of flow separation control with nanosecond pulsed plasma actuation is performed at flow velocity up to 40 m/s. The effects of the actuation frequency and voltage on the aerodynamic performance of the swept wing are evaluated by the balanced force and pressure measurements in the wind tunnel. At last, the performances on separation flow control of the three types of actuators with plane and saw-toothed exposed electrodes are compared. The optimal actua- tion frequency for the flow separation control on the swept wing is detected, namely the reduced frequency is 0.775, which is different from 2-D airfoil separation control. There exists a threshold voltage for the low swept wing flow control. Before the threshold voltage, as the actuation voltage increases, the control effects become better. The maximum lift is increased by 23.1% with the drag decreased by 22.4% at 14°, compared with the base line. However, the best effects are obtained on actuator with plane exposed electrode in the low-speed experiment and the abilities of saw-toothed actuators are expected to be verified under high-speed conditions.

关键词： Dielectric barrier discharge flow control flow separation Nanosecond pulse Plasma Swept wing

flow separation and Vortex Dynamics in Waves Propagating over A Submerged Quartercircular Breakwater

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China Ocean Engineering 2018年第5期32卷 514-523页

作者： JIANG Xue-lian YANG Tian ZOU Qing-ping GU Han-bin Tianjin Key Laboratory of Soft Soil Characteristics & Engineering Environment Tianjin Chengjian University State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University The Lyell Centre for Earth and Marine Science and Technology Institute for Infrastructure and EnvironmentHeriot-Watt University School of Naval Architecture &Mechanical-Electrical Engineering Zhejiang Ocean University

The interactions of cnoidal waves with a submerged quartercircular breakwater are investigated by a ReynoldsAveraged Navier–Stokes(RANS) flow solver with a Volume of Fluid(VOF) surface capturing scheme(RANSVOF) model. The vertical variation of the instantaneous velocity indicates that flow separation occurs at the boundary layer near the breakwater. The temporal evolution of the velocity and vorticity fields demonstrates vortex generation and shedding around the submerged quartercircular breakwater due to the flow separation. An empirical relationship between the vortex intensity and a few hydrodynamic parameters is proposed based on parametric analysis. In addition, the instantaneous and time-averaged vorticity fields reveal a pair of vortices of opposite signs at the breakwater which are expected to have significant effect on sediment entrainment, suspension, and transportation,therefore, scour on the leeside of the breakwater.

关键词： submerged quartercircular breakwater cnoidal wave flow separation vortex dynamics scour

A model of flow separation controlled by dielectric barrier discharge

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Chinese Journal of Aeronautics 2017年第5期30卷 1660-1669页

作者： Mohammadreza BARZEGARAN Amirreza KOSARI Faculty of New Science and Technologies University of Tehran Tehran *** Iran

flow separation, as an aerodynamic phenomenon, occurs in specific conditions. The conditions are studied in a wind tunnel on different airfoils. The phenomenon can be delayed or suppressed by exerting an external momentum to the flow. Dielectric barrier discharge actuators arranged in a row of 8 and perpendicular to the flow direction can delay flow separation by exerting the momentum. In this study, a mathematical model is developed to predict a parameter, which is utilized to represent flow separation on an NACA0012 airfoil. The model is based on the neurofuzzy method applied to experimental datasets. The neuro model is trained in different flow conditions and the parameter is measured by pressure sensors.

关键词： Dielectric barrier discharge flow separation Mathematical model NACA0012 airfoil Neuro-fuzzy

Control of flow separation over a wing model with plasma synthetic jets

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Plasma Science and Technology 2022年第6期24卷 135-147页

作者： Zhi SU Guozheng SONG Haohua ZONG Hua LIANG Jun LI Like XIE Xuecheng LIU Weiliang KONG Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi'an 710038People's Republic of China Institute of Aero-Engine School of Mechanical EngineeringXi’an Jiaotong UniversityXi'an 710049People's Republic of China The Green Aerotechnics Research Institute of Chongqing Jiaotong University Chongqing 404100People's Republic of China

An array of 30 plasma synthetic jet actuators(PSJAs)is deployed using a modified multichannel discharge circuit to suppress the flow separation over a straight-wing *** lift and drag of the wing model are measured by a force balance,and the velocity fields over the suction surface are captured by a particle imaging velocimetry *** show that the flow separation of the straight wing originates from the middle of the model and expands towards the wingtips as the angle of attack *** flow separation can be suppressed effectively by the PSJAs *** best flow control effect is achieved at a dimensionless discharge frequency of F^+=1,with the peak lift coefficient increased by 10.5%and the stall angle postponed by 2°.To further optimize the power consumption of the PSJAs,the influence of the density of PSJAs on the flow control effect is investigated.A threshold of the density exits(with the spanwise spacing of PSJAs being 0.2 times of the chord length in the current research),below which the flow control effect starts to deteriorate *** addition,for comparison purposes,a dielectric barrier discharge(DBD)plasma actuator is installed at the same location of the *** the same power consumption,4.9%increase of the peak lift coefficient is achieved by DBD,while that achieved by PSJAs reaches 5.6%.

关键词： flow separation plasma synthetic jet density dielectric barrier discharge

Numerical investigation of flow separation behavior in an over-expanded annular conical aerospike nozzle

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Chinese Journal of Aeronautics 2015年第4期28卷 983-1002页

作者： He Miaosheng Qin Lizi Liu Yu School of Astronautics Beihang University

A three-part numerical investigation has been conducted in order to identify the flow separation behavior––the progression of the shock structure, the flow separation pattern with an increase in the nozzle pressure ratio（NPR）, the prediction of the separation data on the nozzle wall,and the influence of the gas density effect on the flow separation behavior are *** computational results reveal that the annular conical aerospike nozzle is dominated by shock/shock and shock/boundary layer interactions at all calculated NPRs, and the shock physics and associated flow separation behavior are quite *** abnormal flow separation behavior as well as a transition process from no flow separation at highly over-expanded conditions to a restricted shock separation and finally to a free shock separation even at the deign condition can be *** complex shock physics has further influence on the separation data on both the spike and cowl walls, and separation criteria suggested by literatures developed from separation data in conical or bell-type rocket nozzles fail at the prediction of flow separation behavior in the present asymmetric supersonic *** of flow separation with the gas density is distinct for highly overexpanded *** the gas density or reducing mass flow results in a smaller adverse pressure gradient across the separation shock or a weaker shock system, and this is strongly coupled with the flow separation *** computational results agree well with the experimental data in both shock physics and static wall pressure distribution at the specific NPRs, indicating that the computational methodology here is advisable to accurately predict the flow physics.

关键词： Aerodynamics Aerospike nozzle flow simulation flow separation Gas density effect Over-expanded flow Reynolds-averaged Navier-Stokes (RANS)

Effect of Gurney flap on flow separation and aerodynamic performance of an airfoil under rain and icing conditions

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Acta Mechanica Sinica 2020年第3期36卷 659-677页

作者： Hossein Fatahian Hesamoddin Salarian Majid Eshagh Nimvari Jahanfar Khaleghinia Department of Mechanical Engineering Nour BranchIslamic Azad UniversityNourIran Quality Engineering Research Center Nour BranchIslamic Azad UniversityNourIran Faculty of Engineering Amol University of Special Modern TechnologiesAmolIran

In the present study,special attention is paid to numerically investigate the aerodynamic performance of the NACA 0012 airfoil under rain and icing conditions with the aim to better understand the severe aerodynamic performance penalties of aircraft in ***,in order to control the flow separation and improve the aerodynamic performance of the airfoil under critical atmospheric conditions,the Gurney flap with different heights is attached to the trailing edge of the *** simulation is done at a Reynolds number of 3.1 × 105 under different atmospheric conditions including dry,rain,icing and coupling of rain and icing conditions.A two-way momentum coupled Eulerian-Lagrangian multiphase method is used to simulate the process of water film layer formed on the airfoil surface due to *** to the results,accumulation of water due to rainfall and ice accretion on the airfoil surface inevitably provides notable negative effects on the aerodynamic performance of the *** is concluded that icing induces a higher aerodynamic degradation than rain due to very intensive ice *** Gurney flap as a passive flow control method with a favorable height for each condition is very *** maximum increment of the lift-to-drag ratio is achieved by Gurney Hap with a height of 0.01 of airfoil chord length for dry and rain conditions and 0.02 of airfoil chord length for icing and coupling of rain and icing conditions,respectively.

关键词： Airfoil flow separation Aerodynamic performance Gurney flap Rain and icing Multiphase method

Experimental study on airfoil flow separation control via an air-supplement plasma synthetic jet

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Advances in Aerodynamics 2022年第1期4卷 721-742页

作者： Ru-Bing Liu Wen-Tao Wei Hai-Peng Wan Qi Lin Fei Li Kun Tang School of Aerospace Engineering Xiamen UniversityXiamen361102China Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance Xiamen361005China Chengdu Aircraft Design and Research Institute Chengdu610041China Shanghai Aerospace Control Technology Institute Shanghai201100China Rotor Aerodynamics Key Laboratory China Aerodynamics Research and Development CenterMianyang621000China Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi’an710038China

An air-supplement plasma synthetic jet(PSJ)actuator increases the air supplemental volume in the recovery stage and improves the jet energy by attaching a check valve to the chamber of a conventional *** explore the flow control effect and mechanism of the air-supplement actuator,via particle image velocimetry experiments in a low-speed wind tunnel,the flow field and boundary layer characteristics of a two-dimensional airfoil surface under different actuation states were compared for different attack angles and jet *** experimental results show that,compared with the conventional actuation state,the jet energy of the air-supplement PSJ is higher and the indirect mixing effect of the counter-vortex sequence produced by the jet-mainstream interaction is ***,the boundary layer mixing effect is better,which can further suppress flow separation and improve the critical flow separation attack ***,increasing the jet momentum coefficient can enhance the flow control *** findings of this study could provide guidance for the flow control application of air-supplement PSJs.

关键词： Plasma synthetic jet Check valve flow separation Active flow control Air-supplement

Numerical study on flow separation control over NACA0015 aerofoil using electromagnetic fields

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Theoretical & Applied Mechanics Letters 2013年第5期3卷 62-68页

作者： Ahmad Sedaghat Mohammad Ali Badri Department of Mechanical Engineering Isfahan University of Technology Research Institute for Subsea Science & Technology Isfahan University of Technology

In this study, a flow solver was developed based on the governing RANS equations of compressible flows and was further extended to include the effects of electromagnetic forces namely Lorentz forces. Lorentz forces may be added as a source term in the governing fluid flow equations. Numerical studies were carried out for NACA0015 aerofoil at high angles of incidences from 15° to 30° and compared with some available cases of experimental and incompressible numerical solutions. The hydrodynamics performance was improved using a magnetic momentum coefficient of up to 0.048. The size of flow separation zone was decreased or completely eliminated by increasing this coefficient. The overall drag was not changed considerably, however the overall lift was increased up to 80 percent at stall angles.

关键词： tromagnetic field Lorentz force flow separation Navier-Stokes TVD schemes

Influence studyof flow separation on the nozzle vibration response

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Propulsion and Power Research 2016年第2期5卷 108-117页

作者： Geng Li Qin Liu Xuequn Han Yunqiang Guo The 41st Institute of the Academy of China Aerospace Science mnd'Teclmology Corporation Xi'an Shaanxi 710025China

In the present paper,the vibration response difference of the upper stage nozzlewith higher expansion ratio between ground and altitude simulation hot-firing test is *** indicates that the acceleration response of the nozzle under ground hot-firing test is muchhigher than that of the altitude *** order to find the essential reason,the experimentaland numerical simulation studies of the flow separation are developed by using the test *** experimental data show that the nozzle intemal flow occurred flow separation andthe divergence cone intemal wall pressure pulsation increased significantly downstream fromthe separation *** numerical simulation and experimental results indicate that theincrease of internal wall pressure and turbulence pulsating pressure are the substantial reason ofvibration response increasing aggravatingly during the ground firing test.

关键词： Solid rocket motor flow separation Oscillation response Spectrum analysis Test engine nozzle