Journal of aeronautics, astronautics and aviation, Series A最新文献_第6页

Investigation of Separation Control by Boundary Layer Suction applied to a Highly-Loaded Axial Compressor Cascade 高负荷轴流压气机叶栅边界层吸力分离控制研究

Journal of aeronautics, astronautics and aviation, Series A Pub Date : 2017-09-01 DOI: 10.6125/17-0313-934

X. Mao, Bo Liu, F. Yuan

{"title":"Investigation of Separation Control by Boundary Layer Suction applied to a Highly-Loaded Axial Compressor Cascade","authors":"X. Mao, Bo Liu, F. Yuan","doi":"10.6125/17-0313-934","DOIUrl":"https://doi.org/10.6125/17-0313-934","url":null,"abstract":"Computational method has been used to increase the physical understanding of the separation control by boundary layer suction in a highly-loaded axial compressor cascade. The investigated cascade in current paper has separations both on the suction surface (SS) along the whole blade span and three-dimensional separation in the hub corner. The results show that the flow structure can be changed after the suction, which leads to the variation of loss and blockage generation. The suction scheme on the SS can effectively control the boundary layer separation near trailing edge and to some extent mitigate the three-dimensional separation. The displacement thickness of the three-dimensional separation cannot be simply used to evaluate the overall performance due to the existence of the boundary layer separation on the SS, the variation of the flow pattern and vortex structures should also be considered. The effectiveness and mechanisms varies by conducting suction control at different development stage of the secondary flow. Applying suction control is suitable at the early development stage, and the earlier the better, while it is inappropriate to carry out the control at the middle development stage. The suction control at the late development stage is another relative effective method.","PeriodicalId":335344,"journal":{"name":"Journal of aeronautics, astronautics and aviation, Series A","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114981160","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: 0

Improving single-epoch RTK positioning under higher ionospheric influences using GNSS measurements 利用GNSS测量改进电离层影响下的单历元RTK定位

Journal of aeronautics, astronautics and aviation, Series A Pub Date : 2017-06-01 DOI: 10.6125/17-0110-922

F. Chu, Ming-Jun Yang, Yan Chen

引用次数: 0

Mitigation of Ionospheric Effect on Multi-GNSS Positioning with Ionosphere Delay Estimation Using Single-Frequency Measurements of Selected Satellites 利用选定卫星单频测量估计电离层延迟，减缓电离层对多gnss定位的影响

Journal of aeronautics, astronautics and aviation, Series A Pub Date : 2017-06-01 DOI: 10.6125/17-0123-927

Natsuki Kinugasa, F. Takahashi, R. Kohno

{"title":"Mitigation of Ionospheric Effect on Multi-GNSS Positioning with Ionosphere Delay Estimation Using Single-Frequency Measurements of Selected Satellites","authors":"Natsuki Kinugasa, F. Takahashi, R. Kohno","doi":"10.6125/17-0123-927","DOIUrl":"https://doi.org/10.6125/17-0123-927","url":null,"abstract":"Ionosphere delay is the largest source of positioning error for single point positioning using single-frequency receiver of global navigation satellite system (GNSS). To mitigate the effect of ionosphere which varies sometimes rapidly and locally due to the solar activity, we propose estimating the ionosphere delay in the process of positioning calculation by using the ionospheric thin shell model with single-frequency pseudorange measurement of single epoch. Since sufficient number of visible satellites is observable for multi-GNSS positioning, all those measurements are not necessarily used. We propose algorithm of selecting useful satellites by the residual ranging error of pseudorange measurement to mitigate the positioning error. The performance evaluation for proposed selection algorithm and ionosphere delay estimation was conducted by using L1 pseudorange measurements of global positioning system (GPS) and GLONASS on both quiet and disturbed ionospheric conditions. Proposed selection algorithm reduced the rms of horizontal positioning error by about 10% on disturbed condition. Proposed ionosphere delay estimation increased the average of horizontal error reduction by 30% in daytime on disturbed condition, compared with the conventional correction method using Klobuchar model.","PeriodicalId":335344,"journal":{"name":"Journal of aeronautics, astronautics and aviation, Series A","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125073645","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: 2

Evaluation Algorithm Based on Markov Process for GPS Per-slot and Constellation Availability 基于马尔可夫过程的GPS每时隙和星座可用性评估算法

Journal of aeronautics, astronautics and aviation, Series A Pub Date : 2017-06-01 DOI: 10.6125/17-0108-920

Ershen Wang, Zhi-ming Hu, Pingping Qu, Tao Pang, Yi Jiang, Jia-mei Chen

{"title":"Evaluation Algorithm Based on Markov Process for GPS Per-slot and Constellation Availability","authors":"Ershen Wang, Zhi-ming Hu, Pingping Qu, Tao Pang, Yi Jiang, Jia-mei Chen","doi":"10.6125/17-0108-920","DOIUrl":"https://doi.org/10.6125/17-0108-920","url":null,"abstract":"In civil aviation and other navigation application fields, the per-slot availability and constellation availability of global positioning system (GPS) is a key indicator to evaluate the performance of GPS. In this paper, the per-slot availability and constellation availability of GPS is evaluated and analyzed. Based on Markov process, the model of per-slot availability is set up. In this model, the failure rate and restoration rate of per-slot are taken into account. Moreover, combined with the backup situation of satellites, the constellation availability evaluation models of signal-in-space (SIS) and service are proposed. Based on the above evaluation models, the performance of GPS per-slot availability and constellation availability are evaluated by using the measured data. The results show that GPS per-slot availability and constellation availability have had a very high availability probability. The per-slot availability probability is larger than 0.998. And the constellation availability probability of SIS and service can respectively reach 0.999 999 963 and 0.955 3 respectively when there is no faulted satellites. Meanwhile, the results are instructive for the study of the availability performance evaluation of global BeiDou Navigation Satellite System (BDS).","PeriodicalId":335344,"journal":{"name":"Journal of aeronautics, astronautics and aviation, Series A","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130651083","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: 1

Control Performance for Dual Power Quad-Rotor in Quad-Rotor System 四旋翼系统中双功率四旋翼的控制性能

Journal of aeronautics, astronautics and aviation, Series A Pub Date : 2017-03-01 DOI: 10.6125/16-1031-909

Chin-E. Lin, Thanakorn Supsukbaworn

引用次数: 0

Aerodynamic Effects of Unsteady Blade-Tower Interaction 叶片-塔非定常相互作用的气动效应

Journal of aeronautics, astronautics and aviation, Series A Pub Date : 2016-12-01 DOI: 10.6125/16-1201-915

T. Shieh, Shy-Yea Lin, Yang Fuh-Sen, Cheng Yung‐Ting

引用次数: 0

A Numerical Study of Thermal Discharge Effects for Engine Room of Unmanned Aerial Vehicle 无人机机舱热排放效应的数值研究

Journal of aeronautics, astronautics and aviation, Series A Pub Date : 2016-12-01 DOI: 10.6125/16-0714-896

K. Pan, T. Liu

{"title":"A Numerical Study of Thermal Discharge Effects for Engine Room of Unmanned Aerial Vehicle","authors":"K. Pan, T. Liu","doi":"10.6125/16-0714-896","DOIUrl":"https://doi.org/10.6125/16-0714-896","url":null,"abstract":"With continued innovations and breakthroughs in modern aviation technologies, it made Unmanned Aerial Vehicles (UAVs) to possess diverse development and application. Recently, considerable endeavor is being made in order to extend the cruise range of UAVs, while UAV propulsion systems play a key role. In the past, studies involving the design and development of UAV propulsion systems often employed experiment to determine whether the design of engine shrouds and its inner space allocation could effectively channel cool air into the engine room and achieve exhaust emission and thermal radiation. However, obtaining information for the related flow fields through experimental testing is difficult. Hence, in this study, we developed a structure of large-scale UAV and adopted a numerical method to simulate cool air channeled into the engine room to investigate the internal heat distribution conditions. Furthermore, we used Sliding Mesh Model (SMM) to simulate the rotation of UAV’s propeller and investigate if the convection effect caused by the propeller increases the exhaust emission from the engine room. The results in this study obtained not only the dynamic flow field of cool air channeled into the UAV engine room but also the essential flow field information to achieve thermal radiation of the UAV engine room. The findings of this study can serve as a reference for researchers in the formulation of optimal thermal radiation designs for engine rooms.","PeriodicalId":335344,"journal":{"name":"Journal of aeronautics, astronautics and aviation, Series A","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132753192","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: 0

DESIGN OF THE OPTIMIZED GEOMETRIC CONFIGURATION OF A DERAILLEUR FOR GEAR SHIFTING THROUGH A CHAIN ON A BICYCLE’S CHAINWHEEL 通过自行车链轮上的链条换挡的变速器的优化几何结构设计

Journal of aeronautics, astronautics and aviation, Series A Pub Date : 2016-12-01 DOI: 10.6125/16-1026-908

S. Chiou, Yingku Ma

{"title":"DESIGN OF THE OPTIMIZED GEOMETRIC CONFIGURATION OF A DERAILLEUR FOR GEAR SHIFTING THROUGH A CHAIN ON A BICYCLE’S CHAINWHEEL","authors":"S. Chiou, Yingku Ma","doi":"10.6125/16-1026-908","DOIUrl":"https://doi.org/10.6125/16-1026-908","url":null,"abstract":"The chain and derailleur both are important components in a sprocket-driven transmission system. However, some factors such as force applied, force direction, and geometric configuration of a derailleur, which drew scant attention in design of a conventional sprocket. Generally, short yaw of chain link and scarcity of derailleur force induce the chain to straddle on a target sprocket, even make engaged links drop to original one. Thus, gear shifting would be failure. In fact, the proper force applied and direction will contribute to mitigate lateral forces and tensile forces applied on chain links, accelerate the process of chain shifts, extend the service life of chain and sprockets, and reduce vibrations or noises in the process of gear shifting, even improve the efficiency of chain shifts. The purpose of the geometric design for derailleur is to derive an optimal profile that the minimum force applied on. Base on above, all contact points in the optimal trajectory are not linear arrangement between derailleur and chain. In this paper, the optimal geometric configuration of derailleur is formed by employing difference theory of quazi-dynamic equilibrium for transmission chain as the optimal path is derived.","PeriodicalId":335344,"journal":{"name":"Journal of aeronautics, astronautics and aviation, Series A","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131507426","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: 0

DSMC Simulation of Hypersonic Flows over a Compression Ramp Using Subcell Scheme 基于子单元格式的高超声速压缩坡道流动的DSMC模拟

Journal of aeronautics, astronautics and aviation, Series A Pub Date : 2016-09-01 DOI: 10.6125/16-0528-892

X. Shao, Bin Zhang, L. Li, Hao Chen

{"title":"DSMC Simulation of Hypersonic Flows over a Compression Ramp Using Subcell Scheme","authors":"X. Shao, Bin Zhang, L. Li, Hao Chen","doi":"10.6125/16-0528-892","DOIUrl":"https://doi.org/10.6125/16-0528-892","url":null,"abstract":"Accurate prediction of the surface properties and the recirculation zone is very imperative for the design of advanced hypersonic vehicles and thermal protection. The objective of this paper is to identify the predominant factor affecting the accuracy of the calculation and to propose a more efficient way to simulate the shock wave/boundary layer interaction flow. First, the hypersonic flow over a compression ramp of 35-degree is calculated by the parallel direct simulation Monte Carlo (DSMC), and the results are compared with the benchmark to get a grid resolution. Then, the subcell scheme is implemented and the computational efficiency is highly improved. It is recommended to use a relatively coarse grid with subcell scheme to get a reliable result efficiently in engineering. It also can be found that the SOF, which is the ratio of mean collision separation (MCS) of the particles to mean free path (MFP), plays an important role in the accurate prediction of the recirculation zone, surface pressure and heat flux coefficient. Furthermore, further study show it is not a necessary condition to maintain the SOF value below unity throughout the flow field. More attention should be given to the SOF value in the cells close to the wall.","PeriodicalId":335344,"journal":{"name":"Journal of aeronautics, astronautics and aviation, Series A","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130697803","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: 0

Thermal Buckling, Vibration and Flutter of Composite Laminates Containing Two Non-uniformly Distributed Fibers 含两种非均匀分布纤维的复合材料层板的热屈曲、振动和颤振

Journal of aeronautics, astronautics and aviation, Series A Pub Date : 2016-09-01 DOI: 10.6125/16-0505-888

Shih-Yao Kuo

引用次数: 3