bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research on Longitudinal dynamic characteristics of flexible waverider based on CFD/CSD/RBD method
Authors: Shang Y M , Hua R H , Yuan X X , Tang Z G , Wang Z W 
Published: February 2021

Abstract
The shape of hypersonic aircrafts represented by the waveriders is becoming more slender and flatter, thereby greatly reducing the structural rigidity of the aircrafts. This innovation is applied to satisfy the demand of long-range flight. In this paper, the effect of elastic deformation on the trimming and dynamic stability of the waverider was analysed through Computational Fluid Dynamics(CFD)/Computational Structural Dynamics(CSD)/Rigid Body Dynamics(RBD) coupling. The results show that as the decline of structural stiffness, the angle of attack increases and the lift-drag ratio deteriorates when the waverider is trimmed. The elastic deformation makes the dynamic center get forward, and the static stability of waverider becomes poorer. What’s more, the dynamic stability of pitching motion is reduced due to the coupling of rigid-body motion and elastic vibration.
Design and Test Verification of Hybrid Airfoil Based on Multi-objective Genetic Algorithm
Authors: Li Zhao , Yang Guangjun , Tong Xiaoyan , Jiang Feng 
Published: February 2021

Abstract
Certification of modern aircraft requires the manufacturers to demonstrate flight safety within the flight envelope, including icing conditions. Icing wind tunnel test is an important way for flight safety and certification. However, the size of aircraft models that can be tested in icing wind tunnels is limited by the dimensions of the facilities. It is an effective method to replace the large model with a hybrid airfoil to carry out the experiment. If properly designed, these hybrid airfoil models can generate the full-scale ice accretion on the leading edge and reduce blockage. Based on the similarity of flow field in the leading edge, a multi-objective genetic optimization algorithm is proposed to design the hybrid airfoil under different conditions. The pressure tests are carried out and compared with the leading edge pressure coefficient of the corresponding full-scale airfoils. The design and experimental results show that the pressure coefficient deviation between the hybrid airfoils designed and the corresponding full-scale airfoil in the 15% chord length range of the leading edge is within 3%. Finally, icing wind tunnel test is used to inspect the ice shape of full-scale and hybrid airfoils, and the results shows that ice accretion process have good agreement of hybrid and full-scale airfoils.
Fracture failure analysis on swivel nut of 30CrMnSiA steel in aircraft
Authors: Chen Cheng , Chen Zhen , Li Shangqiang , Zhu Jinpeng , Li Tianxiang , Bian Haiqing 
Published: February 2021

Abstract
In this work, the cracks of HB4-49-14CdD swivel nut in aircraft were found and analyzed by macroscopic observation, morphology testing and metallographic examination. In order to figure out the cause of cracks, manufacturing and assembling process were investigated, and finite element method was used to simulate the tightening process. The results showed that overload tightening torque lead to the fracture and failure of swivel nut.
Modeling and Analysis of Customer Preference in Civil Aircraft Manufacturing Supervision
Authors: Feng Yu , Lei Hua 
Published: February 2021

Abstract
Customer manufacturing supervision of civil aircraft refers to the operator of the aircraft or its authorized entity’s supervision and inspection process during aircraft’s manufacturing and final assembly, through which the operator (airline company) ensures that the delivered aircrafts meet the requirements of approved technical standards, process specifications, and engineering documents, as well as confirming that optional components and aircraft’s layout comply with technical standards required by the purchase contract. Manufacturing supervision brings forward aircraft delivery inspection, qualitative improvement of which enables the improvement of efficiency in single aircraft airworthiness inspection, ensuring aircraft’s continued airworthiness. From the manufacture’s perspective, analyzing customer’s needs and preference on manufacture supervision in advance, taking advantage of the relatively long production cycle, disposing proper engineering solutions for manufacture deviations, reducing the business negotiation items due to deviations not only helps reach the goal of customer supervision, but also helps optimize engineering dispositions.
Wall temperature correlation for convective heating prediction of aircraft heat shield in high-enthalpy and chemically reacting flow
Authors: Yang Xiaofeng , Xiao Guangming , Liu Lei , Du Yanxia , Gui Yewei 
Published: February 2021

Abstract
Hypersonic aircrafts and aero-engine combustion chambers both generate non-equilibrium and high-enthalpy flows and bring complex material-relied heat convection performance. The convective heating prediction is difficult due to unknown surface thermal state, leading to poor usability of wall temperature correlation method (WTCM). This paper aims at improving WTCM for convective heating prediction in chemically reacting flows through coupling computation of catalysis on thermal protection materials. Modified WTCM for chemically reacting flows accounts for two distinct physical events driven by temperature gradient and species reaction, which follow the Fourier’s and Fick’s laws, respectively. Preliminary validation testing demonstrates the feasibility of the modified WTCM to rapidly evaluate aerodynamic heating with limited deviation. The current research provides essential technical support for the evaluation and design of hypersonic aircrafts and aero-engine combustion chambers.
Analysis of thermal lubrication characteristics of aero-gear pump journal bearing
Authors: Ning Gao , Li Huacong , Xianwei Liu , Zhu Jiaxing , Wei Shijie 
Published: February 2021

Abstract
In order to study the thermal lubrication characteristics of aero-gear pump journal bearing (APJB) under certain load and low medium viscosity, a APJB numerical model was established based on the combination of Reynolds and adiabatic flow energy equations. The hydrodynamic lubrication and temperature effects on the viscosity are considered and the finite difference method is adopted. The results show that with the increase of APJB width parameters, the eccentricity decreases monotonically, the minimum oil film thickness increases, the friction resistance increases and the end discharge decreases. In addition, the eccentricity of bearing, maximum oil film pressure, end discharge flow and oil film thickness increase with the APJB radial clearance, while the friction and temperature inside the APJB decrease. When the APJB width changes from 21 to 27mm, the maximum oil film temperature and pressure increases by 2.16% and –35.23%, respectively; when the radial clearance changes from 0.0315 to 0.0413mm, the maximum oil film temperature and thickness decrease by 3.03% and 8.99%, respectively.
Fluid-Structure interaction framework based on structured RANS solver
Authors: Cinquegrana Davide , Vitagliano Pier Luigi 
Published: February 2021

Abstract
A Fluid Structure Interaction framework developed at CIRA to deal with multi-physics problems in a partitioned approach is presented. The CIRA multi-block structured flow solver for unsteady Navier-Stokes equations UZEN was updated and tightly coupled with an open-source solver for non-linear structural dynamics in a modular approach. The solvers are glued in space and time through an open source library, able to control the executing processes and to deliver exchanging data by specific adapters. The validity of the framework is tested on vortex-induced vibration effects of a cantilevered beam in low Reynolds flow and on as three-dimensional wing flutter in transonic turbulent flow.
Dynamic Models of Satellite Relative Motion and their effects on Kalman Filter
Authors: Imran Ali , Xuechuan Wang , Xiaokui Yue 
Published: February 2021

Abstract
In this paper we will study the effects of an increasingly complex Kalman filter state transition matrix on the accuracy of the estimation of a non-linear relative navigation system. The propagation model will be constant in all the cases. The measurements are generated using Xu-Wang model and then noise is added. Whereas the process non-linear vector function/propagation matrix of the Kalman filter will be modified. In the first scenario the Clohessy-Wiltshire equations are considered as the basic propagation model of the Kalman Filter. In the second scenario the eccentricity of the chief satellite’s orbit is included in the model of the Kalman Filter. In the 3rd case we are using the model presented by Xu-Wang which incorporates the oblateness of Earth into the Tschauner-Hempel model. The divergence of the Kalman Filter is studied and provides a guideline to design engineers.
Hypersonic boundary layer receptivity on flat plate with blunt leading edge due to acoustic disturbance
Authors: Zhang Yifeng , Chen Jianqiang , Yuan Xianxu , Chen Xi , Xiang Xinghao 
Published: February 2021

Abstract
In the process of hypersonic boundary layer transition, the leading edge receptivity due to free-stream acoustic disturbance provides unstable perturbations in boundary layer with initial amplitudes, which is one of hot issues in the study about transition mechanism. The receptivity of leading edge is influenced by many factors, involving geometry parameters, disturbance types, etc., among which the bluntness plays a key role for generating disturbances. In order to reveal the mechanism of bluntness influence on the boundary layer transition, investigations into the acoustic receptivity on flat plates with sharp and blunt leading edge are carried out. The flow conditions are as follows: Mach number 6, Reynolds number 1e7/m, adiabatic wall. By introducing two-dimensional plane fast and slow acoustic waves into the free-stream, the whole receptivity process of free-stream disturbances passing through shock wave into boundary layer is simulated with high-order accuracy DNS method. With sharp leading edge as a reference, the generation mechanism of the perturbations near blunt leading edge and its influence on the boundary layer downstream are analyzed. Some conclusions are obtained: for acoustic disturbances in hypersonic free-streams, the receptivity mechanism of blunt leading edge is different from that of sharp leading edge; both the fast and the slow mode can be produced respectively near the sharp leading edge by the fast and the slow acoustic wave, while only fast mode appears near the blunt leading edge; the receptivity of blunt leading edge due to the fast acoustic is stronger than that due to slow acoustic, and is also stronger than that of the sharp leading edge in a certain region of boundary layer downstream.
An intelligent polynomial chaos expansion method based upon features selection
Authors: Zhang Wei , Wang Qiang , Yan Chao 
Published: February 2021

Abstract
Polynomial chaos expansion (PCE) method is a common tool for uncertainty quantification (UQ) in fluid mechanics. However, there exists ‘Dimensional Curse’ when the parameters dimension is very high, and large samples are required to solve the PCE function. This would hinder the application of PCE in high dimensions. An intelligent PCE method based on the idea of features selection in machine learning is proposed in this paper. Therefore, only several important features will be selected to construct the PCE function, then fewer samples will be needed to solve the model, and it will be more efficient. Several benchmark functions and an RAE2822 airfoil flow case are utilized to verify the UQ capability of the intelligent PCE. It is proved to be more efficient than the original PCE, with nearly same accuracy.
Bayesian uncertainty analysis of SA turbulence model for backward-facing step simulations
Authors: Jin-ping Li , Ma Ming , Yan Chao 
Published: February 2021

AbstractThe Reynolds averaged Navier-Stokes models are still the workhorse in current engineering applications due to its high efficiency and robustness. However, the closure coefficients (also known as model parameters) of turbulence models are calibrated by model builders according to some fundamental flows, and the values suggested by the model builders may not be applicable to all flow types. In this work, the Bayesian method is applied to recalibrate the closure coefficients of SA turbulence model to improve its performance in backward-facing step problem. The results show that the four parameters Cb1, Cw3, Cv1and κ are well informed by the experimental data of skin friction coefficient. The recalibrated model parameters show better performance than the nominal values in the prediction of skin fiction coefficient.
Multi-dimensional dissipation strategy within advection upstream splitting methods in hypersonic flows
Authors: Shu-sheng Chen , Yang Hua , Fang-jie Cai , Zheng-hong Gao 
Published: February 2021

Abstract
The work develops the multi-dimensional dissipation strategy within advection upstream splitting methods (AUSM) in hypersonic flows based on the affordable shock-stable item by Chen et al. (J. Comput. Phys. 373 (2018) 662-672). This strategy is related to the sear velocity difference and the pressure-based sensing function. It strengthens the robustness of AUSM-family schemes against shock anomalies and meantime preserves shear layer. A series of numerical cases illuminate its potential capability for hypersonic flows, particularly in the extreme situations such as the large aspect ratio of cells, skewed non-orthogonal grid, and unstructured grid.
Transition prediction with hypersonic cross-flow model on HIFiRE-5
Authors: Xing-hao Xiang , Hai-jie Ren , Yi-feng Zhang , Xian-xu Yuan , Jian-qiang Chen , Shu-sheng Chen 
Published: February 2021

Abstract
The work develops a localized hypersonic cross-flow transition criterion considering the influence of cross-flow intensity and surface roughness. A cross-flow extension of hypersonic modified γ-Re θ transition model based on Chant2.0 computing platform is implemented. The extended transition model is used to predict the cross-flow transition on the elliptic cone (HIFiRE-5) in multiple states, and the predicted results are in good accordance with the experimental results.
Linear transfer guidance based on Lyapunov method
Authors: Bai Shengzhou , Han Chao , Sun Xiucong 
Published: February 2021

Abstract
Low-thrust propulsion technology is widely used in space missions. However, traditional methods are not appropriate for the general case. In this study, a linearization Lyapunov method for constant thrust control is proposed. Based on relative orbit elements (ROEs), analytical constant-thrust linear equations are introduced. Moreover, via Lyapunov method, the linear constant-thrust control strategy is obtained. Numerical simulations are conducted to demonstrate the validation of the proposed method. Given different thrust magnitudes, the accuracy meets the requirement in these cases. Thus, it proves to be a practical choice for engineering applications.
DOA estimation for coherent distributed sources based on common spectral peak search
Authors: Li Hao , Bai Yi , Jian Chunxiao , Xu Haiyun , Mei Fengtong 
Published: February 2021

Abstract
Most of the existing DOA estimation algorithms are based on uniform array, whose estimation performance is limited by the shortcoming of small aperture of uniform array, and it is difficult to apply sparse array to DOA estimation of distributed sources. In order to solve the above problems, this paper introduces interqualitative array into DOA estimation of distributed sources, and proposes a DOA estimation algorithm for coherent distributed sources. Because the array element spacing is larger than half wavelength, the direct estimation will produce false peak. In order to eliminate the ambiguity, this paper proves that DOA estimation of two submatrices is performed separately, and its common value is unique, that is, the true incidence Angle. According to this proof, DOA estimation of two submatrices is carried out separately for the one-dimensional DOA estimation scenario of distributed sources, and the common part of the two sets of estimation results is taken as the final estimation result. The complexity analysis and performance verification of this method are also given. Simulation experiments show that the performance of the proposed method is better than that of the DSPE algorithm and TLS-ESPRIT algorithm under the same array number in the one-dimensional DOA estimation scenario.
The integration and development trend of China’s 5G technology and smart cleaning
Authors: Ji Huiying , Huang Hongtao 
Published: February 2021

Abstract
China’s 5G development has achieved a significant leap from the conceptual level to the application level from technical testing and pilot implementation in 2018 to official commercial use in 2019. In 2020, China will accelerate the application of new technologies such as 4K/8K, VR/AR, and increase the supply of high-end information services.At present, the works in this field stay in the imagination of 5G smart and clean level, talking about the grounded products under the 4G foundation, and fail to reflect the technological attributes of China’s 5G application. This article further analyzes the latest applications and development trends of 5G technology in the field of smart cleaning, which is an important theoretical basis for promoting the intelligent and modern development of China’s cleaning industry, and will help the development of smart cleaning industry and the construction of smart cities in China.
Development of dual-polarization weather radar products display platform
Authors: Zhang Qian , Zhang Peng , Zhang Yi , Zheng Yi , Wei Haiwen , Wei Yupeng , Yang Chuanfeng 
Published: February 2021

Abstract
Dual-polarization weather radar is more advanced than doppler weather radar, with higher observation accuracy and more products. Using PHP and Dreamweaver to develop dual-polarization weather radar products display platform. The dual-polarization weather radar products display platform can display ZDR, CC, KDP, HCl, QPE and other dual polarization radar products in real time, and has the function of playing back 30 times products in the past three hours of a single product. Using this platform, forecasters can compare and analyze doppler radar products with dual-polarization radar products to grasp the real-time conditions of short-term strong convective weather better, to improve the accuracy of short-term forecasts, especially disastrous weather forecasts, so as to further exert the advancement and superiority of dual-polarization weather radar. After applications, it shows that the dual-polarization radar products display platform is reliable and stable operation.
Design of embedded application software of 3D camera based on line laser
Authors: Zhang Lei , Zhang Suofei , Yang Hao 
Published: February 2021

Abstract
The embedded application software of the line laser 3D camera running on the Xilinx Zynq7000 SoC which is the control of circuit to extract and transmit the centre of the laser stripe in the line laser 3D contour scanning system to the PC was designed. First, by analysing the functional requirements of the system, a modular software structure for real-time multitasking is proposed, and then the program flow chart, which mainly includes a data acquisition module, parameter configuration module, communication module, and system management module. The system provides two data acquisition channels, namely the original image and the centre point coordinate data, which is convenient for system setup and debugging, and realizes the adjustment of ROI in different scenarios. It has the functions of real-time acquisition of line laser centre point coordinates and online configuration of camera parameters. The debugging of each module can work stably and reliably.
Investigations of different Eu2O3 concentration and synthesizing temperatures on the photoluminescence properties of Sr3Al2O6 phosphors
Authors: Fan Yu , Chen Chin-Ta , Chen Ying-Jun , Lin Pei-Ying , Yang Cheng-Fu 
Published: February 2021

Abstract
x Eu2O3-doped Sr3Al2O6 powders(x=0.0025, 0.005, 0.0075, and 0.01) are synthesized in air using a solid state reaction method. From XRD patterns, we find that the SrCO3, Al2O3, and Sr3Al2O6 phases are observed in all 1000°C-synthesized x Eu2O3-doped Sr3Al2O6 powders, and the diffraction intensities of SrCO3 and Al2O3 phases decrease and that of Sr3Al2O6 phase increases with synthesizing temperature, and SrCO3 and Al2O3 phases disappear at 1200°C and 1300°C, respectively. When we use 240 nm as excitation wavelength, all the photoluminescence (PL) spectra of x Eu2O3-doped Sr3Al2O6 phosphors show that two apparent emission peaks are at wavelengths of 592 nm and 612 nm and one unapparent emission peak is at wavelength of about 658 nm, which are recognized as the 5D0→7F1, 5D0→7F2, and 5D0→7F3 transitions of Eu3+ ions. The emission intensity of main emission peak (592 nm) of x Eu2O3-doped Sr3Al2O6 phosphors is affected by synthesizing temperature and Eu2O3 concentration, and the concentration quench effect is also observed.
Research on application of corner detection in thread vision measurement
Authors: Feng Zibo , You Fucheng , He Junwei 
Published: February 2021

Abstract
With the rapid development of the automation field, automatic inspection of fasteners in the aviation field has become a top priority. It is precious to realize the fast measurement of important information in fastener production by non-contact. This paper aims to detect the optical image detection of the external thread angle of fasteners. We analyze the traditional Ramer algorithm’s contour segmentation steps in separating thread edge from thread bottom arc to obtain accurate thread angle size and thread bottom arc radius. And Harris algorithm is proposed to find corners again by comparison. Finally, using a discrete point curvature to verify the Harris algorithm’s accuracy in corner detection. Meanwhile, by comparing the edge fitted thread angle with the measured thread angle to verify the Harris algorithm’s reliability in corner detection.
Semantic applications for ontological information theory
Authors: Alnahdi Amany K. 
Published: February 2021

Abstract
Information theory is a field that has applications in several scientific domains. This field, which was initially proposed by Claude Shannon, is interdisciplinary; it combines probability, electrical engineering, information engineering, computer science, and statistics. Representing knowledge in information theory provides scientific scholars a resourceful reference for the filed. By learning the precise terminology used in information theory, researchers can discover documents in the domain. In addition, they can communicate knowledge and ideas by using the accurate jargon. A scientific ontology representing knowledge corpus can be implemented digitally by articulating the concepts in the domain of information theory using semantic graphs. These scientific semantic artifacts are valuable with Web 3 technologies. They facilitate searching documents online by providing precise related results. In addition, it is expected that the semantic knowledge to be applicable in Web service applications based on information theory as Web services are software components that communicate information. This work presents an ontology for the Information theory. The ontology conceptualizes the knowledge of information domain by identifying the main concepts, principles, equations, metrics, and history of information theory. The ontology composed of classes, instances, and properties is built using protege, an ontology editor, and is stored in OWL format. Educational applications for the built ontology are indicated.