Aerospace Science and Technology最新文献

{"title":"Numerical study on the combustion characteristics and performances of single and multi-injectors in a scramjet combustor","authors":"Seung-Min Jeong ,&nbsp;Jae-Eun Kim ,&nbsp;Min-Su Kim ,&nbsp;Bu-Kyeng Sung ,&nbsp;Jeong-Yeol Choi ,&nbsp;Kenneth H. Yu","doi":"10.1016/j.ast.2024.109697","DOIUrl":"10.1016/j.ast.2024.109697","url":null,"abstract":"<div><div>The present study numerically investigates the combustion characteristics and performance of a direct-connect gaseous hydrogen-fueled scramjet combustor depending on the injector scheme. A comprehensive numerical simulation was conducted with an improved delayed detached eddy simulation (IDDES) approach. The framework utilized a high-order accurate numerical scheme to ensure the high fidelity of the results. A total of ten cases were considered combining two injector schemes and five injection pressure conditions. Each injector scheme had a similar range of global equivalence ratios. Numerical results revealed the differences in the local dynamics of the counter-rotating vortex pair. The multi-injector case did not maintain the jet's systemic vortex structure, which plays a primary role in the fuel-air mixing and burning. It owes to the interactions between the jet-jet and the jet-wall surface, where the interaction leads to the loss of momentum. This characteristic of the multi-injector makes the fuel-air mixing contact surface get closer to a thin-flat layer, resulting in the flame being anchored on a flat shear layer over the entire combustor. As a result, the combustion efficiency of the multi-injector is much lower than that of the single injector under a similar equivalence ratio range. Present results indicate that the multi-injector, which is expected to increase the combustion performance by maximizing the fuel-air contact surface, may operate in contrast to its original anticipation under certain configurations and conditions. It also suggests that optimizing the combustion performance requires careful design of injector distributions considering the distances and interactions between injector-to-injector and injector-to-wall.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109697"},"PeriodicalIF":5.0,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Iterative control framework with application to guidance and attitude control of rockets","authors":"Xun Liu,&nbsp;Hashem Ashrafiuon,&nbsp;Sergey G. Nersesov","doi":"10.1016/j.ast.2024.109691","DOIUrl":"10.1016/j.ast.2024.109691","url":null,"abstract":"<div><div>Traditional control methods for nonlinear dynamical systems are predicated on verification of complex mathematical conditions related to the existence of a positive-definite Lyapunov function whose value must strictly decrease with time. Rigorous verification of Lyapunov conditions can be extremely difficult in real-world systems with high-dimensional and complex dynamics. In this paper, we present a novel control logic that can be readily applied to a general class of nonlinear systems irrespective of the complexities in their dynamics. The Iterative Control Framework (ICF) is designed to guarantee the convergence of the closed-loop system state to zero <em>without</em> a priori verification of Lyapunov-like conditions. The underlying computational routine runs in the background in real time and reconfigures the control vector at each time step in such a way that when the control input is applied to the system, the system trajectory reaches closer to the desired state. The technique is applicable to a broad class of complex nonlinear systems but is particularly suitable for systems inherently admitting control action of short duration such as missiles, rockets, satellites, and space vehicles. In this work, we focus on the application of ICF to guidance and attitude control of rockets and missiles where actuation is provided via single-use thrusters.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109691"},"PeriodicalIF":5.0,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-equilibrium plasma distribution in the wake of a slender blunted-nose cone in hypersonic flight and its effect on the radar cross section","authors":"Salvatore Esposito ,&nbsp;Andrea Scarabosio ,&nbsp;Giuseppe Vecchi ,&nbsp;Domenic D'Ambrosio","doi":"10.1016/j.ast.2024.109699","DOIUrl":"10.1016/j.ast.2024.109699","url":null,"abstract":"<div><div>This paper presents numerical results in hypersonic aerothermodynamics, a critical field within aerospace engineering, traditionally focusing on reentry capsules and more recently, slender hypersonic vehicles. While capsules typically undergo near-field analysis to assess heat flux and pressure distributions for Thermal Protection System sizing, slender bodies demand additional attention to wake dynamics due to plasma presence. Plasma can significantly affect the Radar Cross Section (RCS) of these vehicles, which require tracking during flight due to their maneuvering and sustained flight capability.</div><div>Utilizing Computational Fluid Dynamics tools, we explore plasma distribution around a slender blunted cone, considering altitudes and Mach number regimes that may characterize gliding or sustained atmospheric hypersonic flight, emphasizing its impact on RCS. Our study integrates an aerothermodynamic model incorporating non-equilibrium relaxation equations for gas composition and energy. By evaluating characteristic plasma quantities, we underscore the importance of wake plasma for subsequent electromagnetic wave analysis, crucial for understanding RCS. Furthermore, we highlight the necessity for collaborative efforts between Computational Fluid Dynamics (CFD) and Computational Electro-Magnetics (CEM) disciplines to address this challenging interdisciplinary problem.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109699"},"PeriodicalIF":5.0,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shock wave and fully turbulent boundary layer interaction controlled by surface arc plasma actuation","authors":"Qiong Wang,&nbsp;Tian Gan,&nbsp;Xiaoyue Xie","doi":"10.1016/j.ast.2024.109687","DOIUrl":"10.1016/j.ast.2024.109687","url":null,"abstract":"<div><div>Experiments were performed to examine the control effect of surface arc plasma actuators on a fully turbulent boundary layer interaction over a 26-deg ramp in a supersonic flow. The experiments utilized a non-invasive schlieren measurement device, along with comprehensive statistical processing techniques. Time-resolved schlieren up to 25 kHz were performed for visualization. Root Mean Square (RMS), Fast Fourier Transformation (FFT), and Proper Orthogonal Decomposition (POD) were performed on the schlieren dataset for structure identification in the interaction flow. A discharge is created between an electrode pair located upstream of a ramp to induce significant disturbances in the turbulent boundary layer. The discharge frequencies employed are <em>f_a</em>=0.5, 1, 2, and 5 kHz. The findings indicate that lower excitation frequencies result in a greater instantaneous energy input to the flow field, while the highest cumulative energy is obtained at 5 kHz over time. The separation region inhibited effect is further verified through the RMS of the schlieren intensity. The separation shock weaken is verified through the FFT of the schlieren intensity. The results indicate that perturbations in the fully turbulent boundary layer interaction flow pattern are more effective for separation shock control and separation region inhibition. It is important to appropriately increase the actuation frequency in order to achieve a certain level of control over the reattachment shock. This control effect is dependent on the total energy injected into the flow field rather than a large energy of a single pulse.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109687"},"PeriodicalIF":5.0,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A nonlinear filter based on GSK for relative navigation using relative orbital elements","authors":"Bing Hua,&nbsp;Xue Gao,&nbsp;Xiaosong Wei","doi":"10.1016/j.ast.2024.109692","DOIUrl":"10.1016/j.ast.2024.109692","url":null,"abstract":"<div><div>Due to the sensitivity of the relative orbital elements model to the measurement noise, the non-stationary heavy-tailed noise(NSHT) induced by the time-varying environment during the relative navigation usually leads to filter divergence. To address this problem, a new nonlinear filter based on Gaussian-Student's-Multivariate K(GSK) mixture distribution is proposed in this paper. A Dirichlet stochastic mixture vector fusing Gaussian, Student's t, and Multivariate K distributions is introduced, thus proposing a GSK mixture distribution modeling measurement likelihood; then the Kullback-Leibler Divergence (KLD) of the true posteriori probability density function(PDF) and the approximate posteriori PDF are minimized by a variational Bayesian(VB) technique to solve for the state and parameter approximate a posteriori estimations, and finally a new nonlinear filter based on the GSK mixture distribution is derived for angles-only relative navigation in time-varying environments. Simulation outcomes indicate that the filter can realize state estimation in non-stationary states effectively with 45.16% higher estimation accuracy than the existing advanced filters.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109692"},"PeriodicalIF":5.0,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing the efficiency and energy capacity of the tri-directional FG nanoplate attached to the piezoelectric patch validated by artificial intelligence","authors":"Wenqing Yang ,&nbsp;Lei Chang ,&nbsp;Khalid A. Alnowibet ,&nbsp;Mohammed El-Meligy","doi":"10.1016/j.ast.2024.109694","DOIUrl":"10.1016/j.ast.2024.109694","url":null,"abstract":"<div><div>Enhancing the efficiency and energy capacity in composite nanoelectromechanical systems (NEMS) holds significant importance in the engineering industry due to its critical role in enhancing the performance, reliability, and safety of aerospace structures and systems. One key area of application is in the development of advanced sensors and actuators. Regarding this issue, in the current work, enhancing the efficiency and energy capacity in the sandwich nanoplate with a tri-directional functionally graded layer and a piezoelectric patch layer is presented. For capturing the size effects, nonlocal strain-stress gradient theory with two size-dependent factors has been presented. The transverse shear deformation factor has an important role in the prediction of the mechanical performance of various structures. So, in the current work, a new four-variable refined quasi-3D logarithmic shear deformation theory has been investigated. Also, for coupling the piezoelectric patch and composite structure, compatibility conditions have been presented. Hamilton's principle with three factors has been presented for obtaining the coupled governing equations of the NEMS. For solving the current electrical system's partial differential equations, an analytical solution procedure has been presented. Also, to have a better understanding of the current electrical system's fundamental frequency, COMSOL tri-physics simulation has been presented. For verification of the results, one of the tools of artificial intelligence via the datasets of the mathematics and COMSOL multi-physics simulations is presented to verify the results for other input data with low computational cost. Finally, the effects of various factors such as the geometry of the piezoelectric patch, FG power index, length scale factor, nonlocal parameter, and location of the piezoelectric patch on the phase velocity have been discussed in detail. One of the important outcomes of the current work is that designers for modeling the NEMS should pay attention to the applied voltage, location, and geometry of the piezoelectric patch.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109694"},"PeriodicalIF":5.0,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the transition mechanism of vibrating low-pressure turbine blades based on large Eddy simulation","authors":"Zhang Yingqiang ,&nbsp;Dong Xu ,&nbsp;Wu Xuan ,&nbsp;Zhang Yanfeng ,&nbsp;LU Xingen ,&nbsp;ZHU Junqiang","doi":"10.1016/j.ast.2024.109695","DOIUrl":"10.1016/j.ast.2024.109695","url":null,"abstract":"<div><div>The low-pressure turbine blades are susceptible to vibration issues due to their thin profiles and large aspect ratios. Blade vibration will significantly affect the evolution of the boundary layer and the flow state. This paper utilizes large eddy simulation to predict the development of the boundary layer on the suction side of low-pressure turbine blades at low Reynolds numbers (<em>Re</em> = 25,000). It introduces different vibration cases to elucidate the mechanisms by which blade vibrations influence boundary layer separation and transition. The study demonstrates that the introduction of vibration cases significantly reduces both the size of the overall spanwise vortices and their roll-up height. A staggered distribution of spanwise vortices, characterized by alternating high and low regions, is observed near the trailing edge of the vibrating blades. The shorter spanwise vortices develop rapidly, nearly traversing the process of hairpin vortices (Λ vortex) generation and development, and directly breaking down into smaller-scale vortices. This accelerates the transition process. Blade vibration primarily promotes turbulence reattachment by facilitating the transition process dominated by the K-H instability mechanism within the separating shear layer. Consequently, it effectively restricts the growth of the separation bubble on the suction side of the blades, significantly reducing aerodynamic losses. Moreover, increasing the vibration frequency within a certain range can amplify these effects, achieving up to a 23% reduction in total pressure loss compared to stationary blades.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109695"},"PeriodicalIF":5.0,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on the flutter characteristics of folding wings with variable swept angles of the outer wing","authors":"Jin-Gang Wang,&nbsp;Xiang-Ying Guo","doi":"10.1016/j.ast.2024.109685","DOIUrl":"10.1016/j.ast.2024.109685","url":null,"abstract":"<div><div>The critical flutter speed, along with the associated stability and safety of a folding-wing aircraft, has been evaluated for variable wing configurations based on traditional designs. Through theoretical analysis and numerical simulation validation, the contributions of parameters such as the hinge stiffness, sweep angle, and folding angle on the flutter and stability of the folding wing are investigated in detail. It is observed that under a specified safe hinge stiffness, the proposed variable-sweep folding-wing configuration can enhance the critical flutter speed at a dangerous folding angle. Through the joint manipulation of the folding and sweep angles, the aerodynamic drag of the folding wing was reduced, thereby enhancing its flight speed and flutter boundaries. This paper aims to provide novel insights into the design and stability analysis of variable-wing configurations.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109685"},"PeriodicalIF":5.0,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Point-enhanced convolutional neural network: A novel deep learning method for transonic wall-bounded flows","authors":"Fernando Tejero,&nbsp;Sanjeeth Sureshbabu,&nbsp;Luca Boscagli,&nbsp;David MacManus","doi":"10.1016/j.ast.2024.109689","DOIUrl":"10.1016/j.ast.2024.109689","url":null,"abstract":"<div><div>Low order models can be used to accelerate engineering design processes. Ideally, these surrogates should meet the conflicting requirements of large design space coverage, high accuracy and fast evaluation. Within the context of aerospace applications at transonic conditions, this can be challenging due to the associated non-linearity of the flow regime. Different methods have been investigated in the past to predict the flow-field around shapes such as airfoils or cylinders. However, they usually have reduced spatial resolution, limiting the prediction capabilities within the boundary layer which is of interest for transonic wall-bounded flows. This work proposes a novel Point-Enhanced Convolutional Neural Network (PCNN) method that combines the advantages of the well-established PointNet and convolutional neural network approaches. The PCNN model has relatively low memory requirements in the training process, preserves the spatial correlation in the domain and has the same resolution as a traditional computational method. The architecture is used for the flow-field prediction of civil aero-engine nacelles in which it is demonstrated that the flow features of peak isentropic Mach number (<span><math><msub><mrow><mi>M</mi></mrow><mrow><mi>i</mi><mi>s</mi></mrow></msub></math></span>), pre-shock isentropic Mach number and shock location (<span><math><mi>X</mi><mo>/</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>n</mi><mi>a</mi><mi>c</mi></mrow></msub></math></span>) are captured within <span><math><mi>Δ</mi><msub><mrow><mi>M</mi></mrow><mrow><mi>i</mi><mi>s</mi></mrow></msub></math></span> = 0.02, <span><math><mi>Δ</mi><msub><mrow><mi>M</mi></mrow><mrow><mi>i</mi><mi>s</mi></mrow></msub><mo>=</mo><mn>0.04</mn></math></span>, <span><math><mi>Δ</mi><mi>X</mi><mo>/</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>n</mi><mi>a</mi><mi>c</mi></mrow></msub><mo>=</mo><mn>0.007</mn></math></span>, respectively. The PCNN model successfully predicts the integral parameters of the boundary layer, in which the incompressible displacement thickness, momentum thickness and shape factor are typically within 5% of the CFD. Overall, the PCNN method is demonstrated for transonic wall-bounded flows for a range of flow physics that include shock waves and shock-induced separation.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109689"},"PeriodicalIF":5.0,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Active maneuver load alleviation for a pitching wing via spanwise-distributed camber morphing","authors":"You Wu ,&nbsp;Jinying Li ,&nbsp;Yuting Dai ,&nbsp;Yongchang Li ,&nbsp;Chao Yang","doi":"10.1016/j.ast.2024.109693","DOIUrl":"10.1016/j.ast.2024.109693","url":null,"abstract":"<div><div>This paper presents the design and verification of a nonlinear model inversion (NMI) controller for the maneuver load alleviation of a pitching oscillating wing based on spanwise-distributed active camber morphing. Recurrent neural networks (RNNs) are used to predict nonlinear and unsteady aerodynamic forces due to wing's large amplitude pitching maneuver, and a fully connected neural network is introduced to build the dynamic inversion of the aeroelastic system for control law design. The inversed system is concatenated with a PI controller to assemble a nonlinear active controller. The controller is first utilized in an offline environment for a 1DoF pitching finite-span wing with spanwise-distributed active camber morphing and then verified in CFD-based fluid-structure-control coupling simulation. The results show that the offline controller could eliminate the maneuver load. In the online CFD-based fluid-structure-control simulation, the bending moment can be alleviated by 38%.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109693"},"PeriodicalIF":5.0,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}