2018 Flow Control Conference最新文献_第6页

Expansion Tube Magnetohydrodynamic Experiments with Argon Test Gas 用氩气进行膨胀管磁流体力学实验

2018 Flow Control Conference Pub Date : 2018-06-24 DOI: 10.2514/6.2018-3754

D. Gildfind, Daniel R. Smith, S. Lewis, Rory C. Kelly, C. James, H. Wei, T. Mcintyre

{"title":"Expansion Tube Magnetohydrodynamic Experiments with Argon Test Gas","authors":"D. Gildfind, Daniel R. Smith, S. Lewis, Rory C. Kelly, C. James, H. Wei, T. Mcintyre","doi":"10.2514/6.2018-3754","DOIUrl":"https://doi.org/10.2514/6.2018-3754","url":null,"abstract":"In this study an expansion tube is used to generate an experiment to study and evaluate the concept of magnetohydrodynamic aerobraking for planetary entry spacecraft. An expansion tube can theoretically generate the required hypersonic flowfield within which ionisation is confined to the shock layer; this is an important characteristic of the true flight case which previous experiments with arcjets have failed to achieve. The first part of this paper explores the operating envelope for The University of Queensland’s X2 expansion tube facility, to identify flow conditions which should produce a significant interaction between the shock layer and an applied magnetic field. Argon test gas was selected for initial experiments due to its simple chemistry and low ionisation enthalpy, and equilibrium chemistry was used to compute the expected properties of the shock layer around a blunt body model. A candidate flow condition was identified for further analysis with finite rate reacting argon CFD, which indicated that relatively short shock layer length scales for the X2 expansion tube would limit the degree of argon ionisation that was generated, however, sufficient ionisation was still expected. Three sphere models were tested: a steel ball, a plain magnet, and a magnet coated with an electrically insulating ceramic paint. It was found that shock stand-off is unchanged between the steel ball and the plain magnet, but increases by approximately 10% for the coated magnet. Spectroscopy revealed that radiance along the stagnation streamline for some, but not all, of the relevant argon wavelengths approximately doubles when a magnet is used, either coated or uncoated. This increase in radiance does not appear to be associated with changes to shock stand-off. Further work is now required to explain the observed phenomena, and also to address some key experimental challenges, which include accurate measurement of shock stand-off and reducing the significant shot-to-shot variability observed for the coated magnet experiments.","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131045431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Swept-Wing Transition Control Using AC-DBD Plasma Actuators 使用AC-DBD等离子体致动器的后掠翼过渡控制

2018 Flow Control Conference Pub Date : 2018-06-24 DOI: 10.2514/6.2018-3215

S. Y. Venkata, M. T. Hehner, J. Serpieri, N. Benard, M. Kotsonis

{"title":"Swept-Wing Transition Control Using AC-DBD Plasma Actuators","authors":"S. Y. Venkata, M. T. Hehner, J. Serpieri, N. Benard, M. Kotsonis","doi":"10.2514/6.2018-3215","DOIUrl":"https://doi.org/10.2514/6.2018-3215","url":null,"abstract":"In the present work, laminar flow control, following the discrete roughness elements (DRE) strategy, also called upstream flow deformation (UFD) was applied on a 45◦ swept-wing at a chord Reynold’s number of Rec = 2.1 · 106 undergoing cross-flow instability (CFI) induced transition. Dielectric barrier discharge (DBD) plasma actuation was employed at a high frequency (fac = 10kHz) for this purpose. Specialized, patterned actuators that generate spanwinse-modulated plasma jets were fabricated using spray-on techniques and positioned near the leading edge. An array of DREs was installed upstream of the plasma forcing to lock the origin and evolution of critical stationary CFI vortices in the boundary layer. Two forcing configurations were investigated-in the first configuration the plasma jets were directly aligned against the incoming CF vortices while in the second the CF vortices passed between adjacent plasma jets. Infrared thermography was used to inspect transition location, while quantitative measurements of the boundary layer were obtained using particle image velocimetry. The obtained results show that the plasma forcing reduces the amplitude of stationary CF modes, thus delaying laminar-to-turbulent transition. In contrast to previous efforts [1], the plasma forcing did not introduce unsteady fluctuations into the boundary layer. The mechanism responsible for the observed transition delay appears to leverage more on localised base-flow modification rather than the DRE/UFD control strategy.","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124539993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Externally Mounted Active Flow Control for External Stores Support System Drag Reduction 外部安装的主动流量控制外部存储支持系统减少阻力

2018 Flow Control Conference Pub Date : 2018-06-24 DOI: 10.2514/6.2018-4027

Maria Blom, Timothy J. Gorman, Matthew Ouellette, Alexander Voronovich, T. Ashcraft, B. Fisk, D. Schatzman, Jacob Wilson

引用次数: 0

Design of Injection and Suction Ducts for Co-Flow Jet Airfoils with Embedded Micro-Compressor Actuator 嵌入式微型压缩机致动器共流射流翼型的进吸管设计

2018 Flow Control Conference Pub Date : 2018-06-24 DOI: 10.2514/6.2018-3062

Yan Ren, Gecheng Zha

{"title":"Design of Injection and Suction Ducts for Co-Flow Jet Airfoils with Embedded Micro-Compressor Actuator","authors":"Yan Ren, Gecheng Zha","doi":"10.2514/6.2018-3062","DOIUrl":"https://doi.org/10.2514/6.2018-3062","url":null,"abstract":"This paper presents the designs of injection and suction ducts of co-flow jet (CFJ) flow control airfoils with embedded micro-compressor actuator in cruise condition. The duct cross section outlines are mathematically modeled as superellipse, which has a parameter η to control the outline shape. Several geometry parameters are taken into consideration during the design process, including the shape parameter η, the cross section area of the duct, the semi major axis and semi minor axis of the superellipse. The aerodynamic performance of the ducts are evaluated via numerical simulations, which employ 3D RANS solver with Spalart-Allmaras (S-A) turbulence model, 3th order WENO scheme for the inviscid fluxes, and 2nd order central differencing for the viscous terms. The ducts inlet and outlet shapes are predetermined according to the micro-compressor performance, and the associated boundary conditions are configured based on the 2D simulation results of CFJ airfoils and microcompressors. The design goal is to eliminate flow separation, maximize the total pressure recovery, and obtain a more uniformly distributed mass flow at the injection duct outlet. The simulation results show that the duct cross section area distribution along the stream wise direction is crucial to control the duct diffusion and flow separation. For the suction duct, the superellipse semi major axis is important to improve the total pressure recovery. For the injection duct, the center body geometry is critical due to the large swirl angle of the flow from the micro-compressor outlet. Moreover, the injection duct guiding vanes can provide a more uniformly distributed mass flow at the duct outlet. Our optimized suction duct presents 99% total pressure recovery. The optimized injection duct shows 95% total pressure recovery without guiding vanes, and shows 93.7% total pressure recovery with guiding vanes.","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121594174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12

A Parametric Study to Explore ns-DBD Plasma Actuation for Aircraft Icing Mitigation 探讨nsdbd等离子体驱动飞机减冰的参数化研究

2018 Flow Control Conference Pub Date : 2018-06-24 DOI: 10.2514/6.2018-3756

Yang Liu, Cem Kolbakir, Hui Hu

{"title":"A Parametric Study to Explore ns-DBD Plasma Actuation for Aircraft Icing Mitigation","authors":"Yang Liu, Cem Kolbakir, Hui Hu","doi":"10.2514/6.2018-3756","DOIUrl":"https://doi.org/10.2514/6.2018-3756","url":null,"abstract":"A parametric study was conducted to explore the thermal characteristics of ns-DBD plasma actuation in different environmental and flight conditions, and evaluate the potential of leveraging ns-DBD plasma actuators for aircraft in-flight icing mitigation. The parametric study was conducted in the unique Icing Research Tunnel available at Iowa State University (i.e., ISU-IRT). While the transient thermal characteristics of ns-DBD plasma actuation over a NACA0012 airfoil/wing model under various test conditions were revealed by using an infrared (IR) thermal imaging system, the anti-icing performances of the ns-DBD plasma actuators under different operational and environmental conditions were also evaluated and compared by using a high-speed imaging system together with the synchronized thermal imaging of the ice accreting surfaces. The impact of incoming airflow velocity, airflow temperature, and AOA of the airfoil/wing model on the thermal characteristics of ns-DBD plasma actuation as well as the anti-icing performances of the ns-DBD plasma actuators at different ns-pulse frequencies and airflow temperatures were systematically investigated, which provided a guideline for the further optimization of ns-DBD plasma actuators tailored specifically for aircraft icing mitigation. It was found that the dynamic heating process of the airfoil/wing surface induced by the ns-DBD plasma actuation is strongly dependent on the environmental parameters, such as the incoming airflow velocity, air temperature, and the AOA of the airfoil/wing model. The findings derived from this study provided a guideline for the further optimization of ns-DBD plasma actuators tailored specifically for aircraft icing mitigation to ensure a much safer and more efficient aircraft operation in atmospheric icing conditions.","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125725349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Correction: Re-orienting the Turbulent flow over an Inclined Cylinder of Finite Aspect ratio 修正:在有限纵横比的倾斜圆柱上重新定向湍流

2018 Flow Control Conference Pub Date : 2018-06-24 DOI: 10.2514/6.2018-4026

Harshad B. Kalyankar, L. Taubert, I. Wygnanski

引用次数: 2

Passive control of a Mach 5.92 flat-plate boundary layer using steady blowing and suction 5.92马赫平板边界层的稳定吹吸被动控制

2018 Flow Control Conference Pub Date : 2018-06-24 DOI: 10.2514/6.2018-3212

Xiaowen Wang

引用次数: 0

Control of separated flows over membrane wings 膜翼分离流的控制

2018 Flow Control Conference Pub Date : 2018-06-24 DOI: 10.2514/6.2018-4249

Jillian Bohnker, K. Breuer