An effective way to improve the flight capability and environmental adaptability of aerospace vehicles is to design a morphing aircraft structure, which can actively change their aerodynamic shape. During different physiological activities, the abdomens of bees are regularly deformed to improve the efficiency of movement. This was used as an inspiration for the design of a nose cone for aerospace vehicles

Trajectory optimization is important in achieving long-range atmospheric entry hypersonic vehicles. However, the trajectory optimization problem for atmospheric entry of hypersonic vehicles is characterized by strong nonlinearity, parameter uncertainties and multiple constraints. This study proposes a novel online trajectory optimization method for hypersonic vehicles based on convex programming and

Due to its easy implementation and comprehensive applicability, surrogate model has been widely used in the aerodynamic design optimization (ADO) of turbomachinery blades. Machine learning method, rapidly developed and applied in many disciplines, is beneficial to model training. The paper works on ADO of a transonic fan rotor by blade sweeping using a supervised learning model method. First, verifications

Experimental studies of the combustion process of circular transverse methane jets in crossflow are carried out both at stable combustion conditions and approaching flameout. It is found that under stable combustion, a steady recirculation zone is formed downstream of the jet, and the mixing coefficient is basically constant under different conditions. Thus, the excess air coefficient in the recirculation

In the current study, we present an efficient and straightforward numerical framework for exploring the responses of functionally graded triply periodic minimal surface (FG-TPMS) microplates. FG-TPMS structures including Primitive (P), Gyroid (G), and I-graph and Wrapped Package-graph (IWP) exhibit numerous potential applications in engineering due to their excellent stiffness-to-weight ratios. The

The article presents a semi-analytical solution for the free vibration problem in bi-directional functionally graded (FG) cylindrical shells with varying thickness, utilizing a modified shear deformation shell theory (MSDT). In this model, the mechanical properties of the cylindrical shells change along both the axial and thickness directions. Classical analytical methods for shell structures often

Small pre-detonators have potential applications in practical pulse detonation engines or rotating detonation engines. The effects of detonation stability parameter and area divergence on flame propagation in capillary tubes are experimentally analyzed using high-speed cinematography. The four mixtures (namely, stoichiometric methane/oxygen, ethylene/oxygen, propane/oxygen and stoichiometric acetylene/oxygen/50%

Aircraft design requires a multitude of aerodynamic data and providing this solely based on high-quality methods such as computational fluid dynamics is prohibitive from a cost and time point of view. Deep learning methods have been proposed as surrogate models to predict aerodynamic quantities, showing great potential at significantly reduced cost. However, most approaches rely on a structured grid

Solid obstacles induce the detonation in premixed gases while causing significant thrust losses. Jet obstacles can alleviate this deficiency, but there have been few studies on multi-group reactive jet obstacles. In this study, a detailed numerical simulation is performed to investigate the selection of the quantity of reactive jet obstacles and examine the effect of the arrangement of different jet

This research examines the natural vibration analysis of magneto-electro-elastic (MEE) functionally graded porous (FGP) plates. The study employs a moving Kriging (MK) meshfree method to analyze the MEE-FGP plates composed of piezoelectric and piezomagnetic materials with both even and uneven distributions of porosity. The electric and magnetic potentials in the three-dimension are assumed to follow

An online navigation ratio identification model based on the gated recurrent unit (GRU) and a state estimation extended Kalman filter (EKF) are proposed under the scenario in which multiple enemy missiles attack a stationary target using a time-cooperative guidance law. The navigation ratio identification is solved as a dynamic problem, and the time-varying navigation ratios of each missile, instead

The existing damage constitutive models for a composite lamina under impact loading have mainly considered four failure modes: longitudinal fiber failure in tension and compression, matrix failure in tension and compression along the transverse direction. However, when subjected to an impact load in the out-of-plane direction, through-thickness compression failure may also occur in laminates. Therefore

Hyperloop aerodynamic characteristics (e.g., the pressure wave in front of the pod) are analyzed experimentally and theoretically in this study. A scaled Hyperloop aerodynamic experimental equipment that has a scale of dpod = 8.75 cm, BR = 0.34 and lt = 16 m is developed; it can be used to run experiments in the range from 160–320 m/s of vpod at approximately 1/1,000 atm (pref = 150 Pa). Further, this

This study presents a comprehensive investigation on functionally graded (FG) graphene reinforced aluminium cantilever rectangular plates under aerodynamic loads. Two-way loosely coupled fluid structure interaction (FSI) is implemented by coupling finite element analysis (FEA) and computational fluid dynamics (CFD). FEA models are developed using FG graphene nanoplatelets (GPL) reinforced aluminium

Communication behavior characterization, signal scheduling and robust control are the main challenges for networked control applications in aero-engine. To address these difficulties, this paper proposes a synthesis and analysis scheme for Takagi–Sugeno (T-S) aero-engine systems subject to scheduling strategies and network-induced factors, in which the multi-node round-robin protocol (MN-RRP) is introduced

The dynamic ground effect (DGE) refers to the take-off and landing process where the distance between airplane and ground constantly changes with time. In the wind tunnel experiment of DGE, fixed plates are often adopted to substitute the moving-belt ground, which will affect experimental reliability. In this paper, the landing process of an airfoil is simulated to study the feasibility of fixed plates

With the increase of the turbine inlet temperature, the thermal load of serpentine nozzles increases greatly, leading to the stiffness degradation and structure deformation. Therefore, efficient cooling technologies are required. There are adverse pressure gradients (APGs) and strong swirl characteristics in the serpentine nozzle. Therefore, the film cooling design of serpentine nozzles faces greater

The combustion of metastable intermixed composites (MICs) containing fluoropolymers is yet still not well understood. In this study, five new Al/MOX/PVDF nanocomposites (MOX: WO2, WO3, CuO, Fe2O3, Bi2O3) are prepared using a high-energy ball milling method. The thermal decomposition behaviors, combustion characteristics, and combustion products of the MICs are compared using TG-DSC, laser ignition

With the increasing use of unmanned aerial vehicle (UAV) clusters, efforts are underway to effectively improve their endurance time and flight altitude. Chained wing technology is such a technology, which makes cluster UAVs form a combination with high aspect ratio through wingtip connection, thus improving the endurance time and flight altitude. However, existing research on chained wing technology

This paper investigates the finite-time tracking control problem for entry vehicle under input saturation and uncertainty. First, a new integral terminal sliding mode surface is devised, which not only renders fast finite-time convergence, but also presents an explicit estimate of settling time. Subsequently, a singularity-free adaptive integral terminal sliding mode control approach is exploited with

Efficient UAV performance and a perfect recovery system are required to achieve the safe and reliable shipborne recovery of fixed-wing UAVs, which is essential for expanding their marine applications. In this study, taking an automatic horizontal-rope shipborne recovery (aHRSR) system as the recovery platform, a joint optimisation method of fixed-wing UAVs combined aerodynamic configuration and control

The impact and aggregation of multiple alumina droplets on the inner wall of the solid rocket motor may generate a larger rebound aggregated droplet or adhere to the wall to form a liquid film. The rebound and adhesion characteristics of the aggregated droplet are of great significance for slag deposition and two-phase flow prediction in the motor. In this paper, the VOF (Volume of fluid) method is

The two-sample numerical updating algorithm of strapdown inertial navigation systems (SINS) for hypersonic vehicles has a relatively large navigation error. To solve this problem, this paper proposes an error-free SINS numerical updating algorithm in the launch-centered Earth-fixed (LCEF) frame. First, the gyroscopes and accelerometers in SINS output angular increment and velocity increment respectively

The interaction of an oblique shock wave with a bow shock in front of a hemisphere at Mach 14.6 is simulated. The configuration corresponds to an experiment performed at the Calspan University of Buffalo Research Center (CUBRC). Several simulations were performed to assess numerical uncertainty and to achieve agreement with the location of the computed and experimental peak surface pressure and heat

The intelligent structural health monitoring system that can evaluate the structural safety online is the future development trend, in which the strength online prediction is the key step. This study developed a machine learning (ML) method to predict the compression-after-impact (CAI) strength of carbon/glass hybrid laminates subjected to multiple impacts at different impact positions online, which

Discontinuity on aerodynamic surfaces leads to notable aerodynamic penalties which could be avoided with compliant fairings. This paper introduces a novel design for a compliant fairing to eliminate the gaps present on hinged aerodynamic surfaces such as hinged wingtips. The fairing is designed to provide a smooth, continuous change in shape between the surfaces on either side of the hinge as they

Results are presented from a RANS study of an asymmetric diffuser with mild separation incorporating a vortex generator (VG) at the entrance. Three types of VGs in the form of a pyramidal ramp, and a pair of vanes that produces an upwash or a downwash respectively in the channel between them. In total, twelve VG configurations were included in this study. The flowfield downstream of the VG was analyzed

This paper investigates the bearing-based formation maneuver control problem for a group of fixed-wing unmanned aerial vehicles. Unlike the existing works that only steer UAV swarm to achieve a fixed geometric pattern, our objective is to enable UAV swarm to maneuver as a group such that the centroid, scale and orientation of the formation can be continuously changed. The underlying graph of UAV swarm

The lobed nozzle is usually used in the exhaust system of military helicopters to improve survivability. The thermal and flow characteristics of the lobed mixer with and without the scalloping structure are investigated to provide a theoretical basis. The delayed detached eddy simulation is used after validated against Hu's experiment of stereoscopic particle image velocimetry. The specific position

The dynamic mixedness characteristics of a bluff-body stabilized turbulent jet under transverse acoustic excitations were investigated using high-repetition-rate acetone planar laser-induced fluorescence (PLIF) at 7 kHz and multipoint scanning hot-wire measurements. Acetone mixedness imaging was applied for the turbulent jet to assess the interaction between the turbulent jet and the imposed transverse

Due to the importance of space manipulators in on-orbit servicing tasks, capturing operations by using a space manipulator, which involves complicated contact has been widely studied. The complicated contact feature brings great challenges to the analysis of the capturing operations. A capturing dynamics model of an end-effector with snare capture and retract operations is developed in this work. The

From current study the flow states of hypersonic inlet are classified into two types: start and unstart. Between start and unstart exists the double solution region, which forms the classical double solution theory of air inlet. However, because the shock in hypersonic inlet strongly interferes and interconnects with the boundary layer, it is very hard for the classical double solution theory to explain

Tip leakage flow directly affects the aerodynamic performance in the turbine stages. In this research, wind tunnel experiments and numerical calculations are performed for the Original Cavity Tip (OCT), the modified Stepped Cavity Tip (SCT) and Cavity Winglet Tip (CWT) with different pressure squealers under seven incidence angles in a range of ±15°. The shape control effects on the aerodynamic performance

This paper presents trajectory planning algorithms for large-scale satellite clusters reconfiguration based on sequential convex programming, and these algorithms consider fuel consumption and collision avoidance. Firstly, the trajectory planning problem is formulated as a nonconvex optimal control problem with nonlinear dynamics and nonconvex path constraints. Secondly, the original nonlinear continuous

This paper explores and analyzes the robust proximity control problem for spacecraft in the presence of external disturbance, model uncertainty, and safety concern. To fulfill the safety proximity requirement, a novel two-stage time-depended performance function is constructed to guarantee the transient and steady-state proximity performance. Then, by assimilating the advantages of the prescribed performance

The working condition of micro-turbine blades is very harsh, which is easy to cause blade faults such as fouling, cracks, and fractures. Therefore, it is of great significance to accurately and timely identify the early faults of turbine blades. In this paper, an early weak fault identification method of micro-turbine blade based on sound pressure signal and long short-term memory (LSTM) networks is

The miniaturized supersonic rocket or missile is an innovative concept most notably characterized by its small caliber, short length, and high flight speed. Tightly coupled design parameters and constrained objectives bring high complexity to launch safety assessments. The commonly used heuristic algorithm NSGA-II cannot address this complexity with its original density estimation strategy. In this

To track a maneuvering hypersonic glide target, an adaptive method for state estimation is proposed with model uncertainties in this paper. Various maneuver modes lead to considerable motion model uncertainty. In the method, unknown aerodynamic accelerations are modeled as the Singer model with a small maneuver frequency. When the real motion mode deviates from the default model, the maneuver frequency

The airfoil probe is typical instrumentation for measuring total pressure/temperature in the research fields of turbomachinery. Besides causing measurement error itself, it also generates extra flow loss inevitably and further affects the measuring accuracy. This paper utilizes the Reynolds-averaged Navier Stokes (RANS) and high-fidelity methods to understand the effects of airfoil probes on the aerodynamic

Unstart flow in a rectangular-to-elliptical shape-transition (REST) inlet at the off-design operating condition has been simulated using the detached eddy simulation (DES) method. With the help of numerical simulations, the development of the unsteady inlet unstart flow at the transitional condition is obtained. The evolution patterns of unstart flow as well as the characteristics at different stages

The DLR Future Fighter Demonstrator (FFD) is a highly agile, two-seated aircraft with twin-engines equipped, a reheat and a design flight speed extending into the supersonic regime (up to Ma=2.0). Based on a given conceptual design, the presented work focuses on the aeroelastic modeling, including structures, masses and aerodynamics. Using the models, a comprehensive loads analysis with 688 maneuver

In order to solve the multidimensional restricted optimization problem of aeroengine acceleration process and improve the acceleration performance of full envelope, a design method of aeroengine full envelope acceleration controller based on deep reinforcement learning is proposed. Firstly, the thermo-aerodynamic principle of the engine acceleration process is analyzed, and the mathematical analytical

Aiming at the terminal impact-angle constraint in the interception of large maneuvering targets, this paper proposes a three-dimensional (3D) interception guidance law combined with the high-order fully-actuated system approach and the cascaded linear extended state observer (LESO). First, a complete second-order nonlinear model with full actuated characteristics is developed for the missile-target

This study numerically investigates the nozzle performance of a rotating detonation engine with film cooling. The premixed stoichiometric hydrogen/air mixture serves as the reactant, and the pure air is pumped into the film cooling holes. The diverging section of the nozzle is designed based on the characteristic method and the maximum thrust theory. The spike truncation ratio is optimized to ΔLspike

Two multi-objective optimization designs of the rotor blade for an axial transonic compressor are carried out in this study. Among them, the optimization of the blade alone is called blade-only optimization. The optimization of the blade integrated with axial slot casing treatment (ASCT) is called blade-integrated optimization. During the optimization stage, the values of sweep and lean in the tip

To study the atomization characteristics of a liquid–centered gas–liquid pintle injector under periodic operating conditions, the gas–liquid interaction, breakup dynamics and spray morphology of the pintle element are simulated based on the three–dimensional volume of fluid to discrete particle model (VOF to DPM) and octree adaptive mesh refinement (AMR) when the liquid jet velocity changes according

Serpentine nozzles possess excellent advantages in improving the stealth ability of aero-engine exhaust. For a real turbofan, the flow characteristics of the serpentine nozzle are evidently affected by the geometric parameters and the complex exhaust mixer. This is an issue that needs to be seriously considered. The aim of this paper is to investigate the influences of the critical geometric parameters

A novel strut with sawtooth grooves arranged at the trailing edge of a normal strut was developed to improve the performance of a scramjet combustor. Through numerical simulations, the cold and hot flow fields of scramjet combustors with normal and novel struts were presented at an inlet Mach number of 2.0. The comparison of numerical results with experimental results has proven the accuracy of the

Two-dimensional simulations were carried out to investigate the flame acceleration and deflagration-to-detonation transition (DDT) in a combustion chamber filled with a subsonic or supersonic mixture by employing Navier-Stokes equations together with a detailed chemistry reaction mechanism of 11 species and 27 steps under adaptive mesh refinement. The effects of the initial mixture Mach number and

A morphing-attitude coupling control method based on event-triggered adaptive dynamic programming (ETADP) and a finite-time fuzzy disturbance observer (FTFDO) is proposed for a class of hypersonic morphing vehicle (HMV). Firstly, an attitude-morphing coupled dynamic model is established, and the morphing variable is treated as the state for integrated control with attitude. The control law is updated

With the increasing demand for the application of multiple quadrotors, improving their autonomous flight ability in unknown environments has become one of the research focuses in the robot field. In this paper, a distributed obstacle avoidance controller is proposed with three elaborate control terms: obstacle avoidance term, inter-robot collision avoidance term, and formation reconstruction. Firstly

The optimization design of the actual fan/compressor rotors is a multidisciplinary problem. The aerodynamics and strength multidisciplinary optimization design of the fan/compressor rotors can improve the aerodynamic performance of rotors as much as possible under the condition of satisfying the structural strength requirements. However, the conventional multidisciplinary optimization of aerodynamics

A comprehensive numerical study is performed to reveal influence of the upstream wall slope on aerodynamic properties as rarefied hypersonic flows pass through the two- and three-dimensional cavity configurations using the direct simulation Monte Carlo (DSMC) method. In this work, slope effect is obtained by the cavity upstream wall sloping upward and downward as well as bulging partially. Besides

The use of integral solutions to the acoustic-analogy-based Ffowcs Williams-Hawkings (FW-H) formulation is the de facto industrial and academic approach for assessing far-field acoustic behavior from airframe noise simulations. The methodology utilizes time-accurate flow variables obtained at arbitrary data surfaces to determine far-field spectra. The solid surface approach, where the time history

In this paper the shallow sandwich panels are considered to be made of the nanocomposite enriched face-sheets and the auxetic honeycomb core so that its Poisson's ratio is negative. In order to evaluate the geometrical nonlinear dynamic behavior of such sandwich panels, various periodic and impulsive loadings are considered. For the sake of solving the governing nonlinear differential equations system

The aerodynamic performance of an isolated coaxial rotor in forward flight is analyzed by a high-fidelity computational fluid dynamics (CFD) approach. The analysis focuses on the high-speed forward flight with an advance ratio of 0.5 or higher, which is the ratio of the forward speed to the rotor tip speed. The effect of the degree of the rolling moment on the rotor thrust, called lift offset, is studied

In the context of aircraft applications, the overall design process can be challenging due to the different aerodynamic requirements at several operating conditions and the total associated computational overhead. For this reason, the use of low order models for the optimisation of complex non-linear problems is sometimes used. This paper addresses the challenge of transonic aerodynamic design optimisation

An axial-flow turbine is one of the main components of aircraft jet engines. It is important to suppress the leakage flow at the blade tip to improve the aerodynamic performance of the turbine blades. To achieve this, a unique ring-type plasma actuator was developed as an active flow control device. This plasma actuator consists of a high-frequency−high-voltage electrode installed in the outer casing

In this work, we develop a 2D numerical model of a Y-shaped bifurcating combustor with a Helmholtz resonator attached. Propane (C3H8) is fueled and burnt with air by applying single-step eddy dissipation combustion model and k−ϵ−RNG turbulence model for simplicity. To validate the numerical findings, experimental measurements are conducted on a bifurcating Y-shaped thermoacoustic combustor with an

Data-driven methods for predicting aerodynamic coefficients of arbitrary shapes have received considerable attention due to their flexibility and scalability. This paper introduces a deep-learning framework based on a deep residual neural network and K-fold cross-validation for fast and accurate prediction of aerodynamic coefficients of a three-dimensional cone with shape changes due to ablation. The