2018 Flow Control Conference最新文献

{"title":"Super-Lift and Thrusting Airfoil of Coflow Jet Actuated by Micro-Compressors","authors":"Gecheng Zha, Yunchao Yang, Yan Ren, B. McBreen","doi":"10.2514/6.2018-3061","DOIUrl":"https://doi.org/10.2514/6.2018-3061","url":null,"abstract":"This paper presents the wind tunnel experimental study of coflow jet (CFJ) active flow control airfoils actuated by micro-compressors embedded inside the airfoils. This is the first time that a CFJ airfoil is successfully controlled by the self-contained zero-net mass-flux (ZNMF) system. It is a crucial step to bringing the CFJ airfoil to practical aerospace applications. Furthermore, this study proves for the first time in experiment that a CFJ airfoil can achieve a Super-Lift Coefficient (SLC), which exceeds the theoretical limit of potential flow theory defined by CLmax = 2π(1 + t/c). The CFJ airfoils studied in this research were modified from the NACA 6421 airfoil geometry with a size of 0.72 m × 2.1 m (chord × span). Two airfoils were tested, one with larger injection slot size for high cruise efficiency and low CFJ power consumption, the other with smaller injection size to achieve high CLmax for takeoff/landing. The freestream velocity varies from about 4.8m/s to 16.2m/s while the Reynolds number varies from 208,000 to 691,000. The CLmax of 8.6 is achieved by the high lift takeoff/landing configuration at the low freestream speed of 4.8m/s. The CFJ airfoil also generates very high thrust with the thrust coefficient up to about 1.0. The thrust is maintained up to the airfoil stall at 40◦ AoA with a drag of CD = −0.5. Since the micro-compressors and the CFJ airfoil were designed separately, they do not work optimally together in the experiment. The micro-compressor operating line is substantially lower the the designed operating line with a severe penalty to the compressor efficiency. Future micro-compressor design needs to be tightly incorporated with the CFJ airfoil operating conditions to make use of the high compressor efficiency.","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"53 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":"132723460","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}

{"title":"Reduced-Order Models for Feedback Control of Transient Energy Growth","authors":"Aniketh Kalur, Maziar S. Hemati","doi":"10.2514/6.2018-3690","DOIUrl":"https://doi.org/10.2514/6.2018-3690","url":null,"abstract":"Feedback flow control is developed to suppress the transient energy growth of flow disturbances in a linearized channel flow. Specifically, we seek a controller that minimizes the maximum transient energy growth, which can be formulated as a linear matrix inequality problem. Solving linear matrix inequality problems can be computationally prohibitive for high-dimensional systems encountered in flow control applications. Thus, we develop reduced-order fluids models using balance truncation and proper orthogonal decomposition techniques. These models are designed to optimally approximate system energy while preserving the input-output dynamics that are essential for controller synthesis. Controllers developed based on these reduced-order models are found to reduce transient energy growth and to outperform linear quadratic controllers in the context of a linearized channel flow.","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"36 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":"125847616","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}

{"title":"Magnetohydrodynamic Drag Force Measurements in an Expansion Tube","authors":"Daniel R. Smith, D. Gildfind, C. James, T. Mcintyre, V. Wheatley","doi":"10.2514/6.2018-3755","DOIUrl":"https://doi.org/10.2514/6.2018-3755","url":null,"abstract":"The use of a magnetic field to manipulate the shock layer for a re-entry vehicle has been proposed as a possible method for increasing drag of planetary entry vehicles. Whilst the field of magnetohydrodynamics (MHD) is well established, the application of this field to planetary entry vehicles is not well understood. The current state of the literature uses analytical, numerical, and experimental means to investigate the feasibility of this technology. However, the validity of the analytical and numerical methods used thus far have not been well validated due to limited experimental data in realistic flow regimes. For this reason, the current paper presents some of the first measurements in this field done in an expansion tube-a type of facility which seems uniquely suited for this type of study. The unique advantage of the expansion tube is that it can generate high enthalpy flows representative of true flight conditions with a non-ionised freestream. This is one of the critical areas for uncertainty in existing experimental data for magnetohydrodynamic aerobraking, which have been predominantly done in arc jet tunnels. Therefore, the focus of the current paper has been on proving that the magnetohydrodynamic force is present and can be measured in an expansion tube. Two different methods have been investigated to achieve this aim. These are accelerometer measurements and strain measurements. Drag force measurements have been taken with several conditions with the accelerometer technique, however issues have arisen with the strain measurements which have prevented data to have been taken. Issues encountered for both methods have been discussed here, and possible solutions are provided. The acceleration measurements have shown that an MHD force can be measured, but further analysis is required to understand these measurements.","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"1 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":"129239837","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}

{"title":"Characterization of the Suction-and-Oscillatory-Blowing actuator by the hybrid RANS-LES CFD","authors":"A. Prachař, P. Vrchota","doi":"10.2514/6.2018-3375","DOIUrl":"https://doi.org/10.2514/6.2018-3375","url":null,"abstract":"","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"11 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":"125533109","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}

{"title":"Transition Manipulation by the Use of an Electrorheologically Driven Membrane","authors":"Thomas Schomberg, Florian Gerland, F. Liese, O. Wünsch, Markus Ruetten","doi":"10.2514/6.2018-3213","DOIUrl":"https://doi.org/10.2514/6.2018-3213","url":null,"abstract":"","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"15 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":"121615961","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}

{"title":"Configuration Studies for a Plasma Actuator Technique using Arc Breakdown in a Magnetic Field","authors":"J. Zimmerman, G. Hristov, Moiz Vahora, Phillip J. Ansell, D. Carroll","doi":"10.2514/6.2018-3758","DOIUrl":"https://doi.org/10.2514/6.2018-3758","url":null,"abstract":"","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"34 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":"134621329","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}

{"title":"Steady and Unsteady Excitation of Separated Flow over the NASA Hump Model","authors":"M. Koklu","doi":"10.2514/6.2018-4016","DOIUrl":"https://doi.org/10.2514/6.2018-4016","url":null,"abstract":"Separated flow and its control over the NASA hump model were investigated at subsonic speeds. Three-dimensional, unsteady fluid dynamic simulations were supplemented by wind tunnel measurements. Flow control was implemented by means of spatially distributed discrete jets operating in steady and unsteady modes. The effects of excitation amplitude and frequency were studied numerically and experimentally. Several integral parameters were explored as quality metrics. In addition to the existing ones, two new integral parameters, which are slightly modified versions of the normal force and moment coefficients, were introduced. These two parameters together with pressure drag coefficient were found to be well correlated with the flow control and used in the performance evaluation of different flow control methods including, zero net mass flux actuators, steady suction, sweeping jet actuators, and the currently studied steady and unsteady excitations. For the cases tested, it was found that the unsteady excitation is superior to the steady excitation and slightly better than the sweeping jet actuators whereas the steady suction was found to be the most effective. Although the numerical simulations overpredict the separation bubble, these simulations capture the salient features of flow separation control and hence help us to understand the effect of steady/unsteady excitation on the separated flow. splitter plate, and the jet nozzles. Several integral parameters were explored to evaluate different flow configurations. The performance evaluation of different flow control methods including the current and previously tested methods was performed using the integral parameters. low amplitude excitations ( C µ = 0.11%). Results of zero net mass flux (ZNMF) actuators, sweeping jet (SWJ) actuators from previous studies were compared to the currently studied steady and unsteady excitations. Although all AFC methods increased the upstream suction pressure and pressure recovery downstream, the ZNMF actuators were found to be the least effective at this configuration. The ZNMF actuators generated an even higher-pressure drag coefficient although the separation bubble was reported to be reduced. The current unsteady excitation was found to be the most effective AFC method, closely followed by the SWJ actuators. The AFC methods were also compared at slightly higher amplitudes ( C µ = 0.24%).","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"15 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":"114313153","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}

{"title":"Friction Drag Reduction on a Clark-Y Airfoil Using Uniform Blowing","authors":"Kaoruko Eto, Y. Kondo, K. Fukagata, N. Tokugawa","doi":"10.2514/6.2018-3374","DOIUrl":"https://doi.org/10.2514/6.2018-3374","url":null,"abstract":"","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"35 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":"117083995","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}

{"title":"Comparison of Different Vortex Generating Devices for Flow Control on a Vertical Tail","authors":"Vickram M. Singh, P. Scholz","doi":"10.2514/6.2018-4023","DOIUrl":"https://doi.org/10.2514/6.2018-4023","url":null,"abstract":"","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"237 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":"116058434","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}

{"title":"Experiments on a Dynamic Bubble Burst Control Plate for Airfoil Stall Suppression","authors":"Homare Yamato, Shohei Asai, Y. Sunada, K. Rinoie","doi":"10.2514/6.2018-3685","DOIUrl":"https://doi.org/10.2514/6.2018-3685","url":null,"abstract":"","PeriodicalId":144668,"journal":{"name":"2018 Flow Control Conference","volume":"29 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":"115246570","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}