Sinusoidal leading-edge wings have shown a high performance after the stall region. In this study, the role of smart flaps in the aerodynamics of smooth and sinusoidal leading-edge wings at low Reynolds numbers of 29,000, 40,000 and 58,000 is investigated. Four wings with NACA 634-021 profile are firstly designed and then manufactured by a 3 D printer. Beam bending equation is used to determine the

Simple reduced order models (ROMs) for the aerodynamic coefficients - lift, drag, and pitch moment - of a pitching NACA0012 airfoil are presented. The ROMs are designed for quick computation of the transient aerodynamic characteristics of the airfoil and are developed utilizing computational fluid dynamics (CFD) simulation results. The entire aerodynamic system is modeled as a single input, multi output

During aircraft maneuvering flights, engine's rotor-bearing systems are subjected to parametric excitations and additional inertial forces, which may cause severe vibration and abnormal operation. Based on Lagrange's principle combined with finite element modeling, the differential equations of motion for a squeeze film damped rotor-bearing system mounted on an aircraft in maneuvering flight are derived

This paper addresses a multisource localization problem with multiple unmanned aerial vehicles equipped with appropriate sensors coordinating with each other, wherein the sources are simultaneously emitting identical acoustic signals. Distributed coordinated localization algorithms based on multiple range and direction measurements are presented and performances are evaluated in different practically

Loss-of-control has become the largest fatal accident category for worldwide commercial jet accidents, and any initiative aimed at preventing such events requires an understanding of the fundamental aircraft behavior, especially the flight dynamics at post-stall region at which loss-of-control usually occurred. A series of low-speed static and dynamic wind tunnel tests of the Common Research Model

Considering the supersonic inlet model with normal shock position feedback, the integrated control method of inlet and turbofan engine is studied. The integrated model includes the supersonic inlet model and the component level model of engine. Combining the relationship between the normal shock position and the total pressure recovery coefficient, the supersonic inlet and engine model is constructed

Traditional electro-thermal de-icing strategy has the drawback of high energy consumption and its heat knife accounts for a considerable amount of the cost. Compared to electro-thermal de-icing, thermo-mechanical expulsion de-icing system eliminates the heat knife by combining electric-heating with electro-magnetic expulsion de-icing system. The consumption is significantly lower but the system has

An impact angle control guidance law is proposed for stationary target interception considering missile's field-of-view limit and speed changes. The proposed impact angle control guidance law is structured as a biased proportional navigation with a time-varying bias. The proposed guidance law does not involve any switching logic for maintaining lock-on; hence, the guidance command is continuous during

Experimental and numerical analyses were performed on a low-speed axial compressor rotor to investigate the aerodynamic and acoustic effects of axial skewed slots casing treatment on the rotating instability. The experimental results showed that the stall margin could be improved by 8.0% and the frequency broadband hump owing to the rotating instability was suppressed effectively. In the noise spectra

This investigation aims to understand the mechanisms of affecting the axial flow compressor performance and internal flow field with the application of self-recirculation casing treatment. Besides, the potentiality of further enhancing the compressor performance and stability by optimizing the geometric structure of self-recirculation casing treatment is discussed in detail. The results show that self-recirculation

Many existing state estimation approaches assume that the measurement noise of sensors is Gaussian. However, in unmanned aerial vehicles tracking applications with distributed passive radar array, the measurements suffer from quantization noise due to limited communication bandwidth. In this paper, a novel state estimation algorithm referred to as the quantized feedback particle filter is proposed

In this research, the effect of Gurney flap on the aerodynamic behavior of an airfoil in mutational ground effect is investigated. To perform this, lift and drag coefficients of NACA 4412 airfoil section in the presence and absence of Gurney flap in mutational ground effect are evaluated and compared. To provide a better illustration of the effect of Gurney flap on the aerodynamic behavior of the airfoil

A numerical methodology based on the coupling of computational fluid dynamics (CFD) and computational structural dynamics is established to obtain the trimming characteristics of flexible aircrafts in this paper. Reynolds-averaged Navier–Stokes equations are solved through CFD technique. Based on the frame of unstructured mesh, techniques of dynamic chimera mesh and morphing mesh are adopted to treat

The ground-based spacecraft dynamics simulator plays an important role in the implementation and validation of attitude control scenarios before a mission. The development of a comprehensive mathematical model of the platform is one of the indispensable and challenging steps during the control design process. A precise mathematical model should include mass properties, disturbances forces, mathematical

In this work, a design strategy for optimising thin-walled structures based on a global-local finite element (FE) modelling approach is presented. The preliminary design of thin-walled structures can be stated in the form of a constrained non-linear programming problem (CNLPP) involving requirements of different nature intervening at the different scales of the structure. The proposed multi-scale optimisation

Auxiliary power unit is one of the indispensable systems for civil aviation aircraft but the traditional planned maintenance cannot meet the actual needs of airlines. In this work, the key performance parameters of the auxiliary power unit are selected by using recursive feature elimination method. With the selected parameters, the remaining useful flight cycle of the auxiliary power unit is predicted

This paper studies the problem of autonomous rendezvous in the libration point orbit without relative velocity measurement information. The proposed rendezvous algorithm consists of the finite-time-convergent differentiator and the finite-time prescribed performance controller. Wherein, the differentiator is used to compute the unknown relative velocity between the target and the chaser spacecraft

The article describes the proposition for developing the similar dynamically downscaled model of a medium range passenger aircraft and its application for researches in area of aerodynamics and flight dynamics. Computer simulations of aerodynamic flows are commonly used in advanced aircraft designing. Numerous data on the characteristics of an airplane can be obtained from tunnel tests of geometrically

This paper puts forward realizing the synchronous control of spacecraft attitude and micro-vibration by taking advantage of magnetic suspension rotor deflection of magnetically suspended control and sensitive gyro. A disturbance-observer is designed to estimate the complex micro vibration which is hard to measure, and an adaptive robust sliding mode controller is designed as an integrated controller

The internal drag of the unconventional inner flow channel of blended wing body aircraft must be measured accurately to correct the air intake effect of the blended wing body flow-through model in wind tunnel tests. In this study, the pressure distribution of the inner flow channel under the interaction of internal and external flows was obtained through numerical simulation. A specialized pressure-measuring

An accurate computation of near-field unsteady turbulent flow around aerofoil is of outstanding importance for aerofoil trailing edge noise source prediction, which is a representative of main contributor to airframe noise and fan noise in modern commercial aircraft. In this study, an embedded large eddy simulation (ELES) is fully implemented in a separation-induced transitional flow over NACA0012

The article describes the vibration measurement technology used in experimental investigation of light aircraft and some series of exemplary results obtained during the prototyping process. The aim of investigations presented herein was to determine the resonant frequencies and natural modes of an aircraft or its selected structural components. Ground vibration testing is an essential dynamic structural

This report investigates the flight dynamics of a small-scale (2 ft) towed system using a quadcopter and actively controlled payload. A towed system includes a main driver to propel the system forward connected to a payload via a tether. The towed system here is unique, and in that the driver is a scratch built quadcopter while the payload is also a scratch built actively controlled aircraft. The payload

Adhesive bonding is a predominant bonding technique in the aeronautical and automotive industries. Cohesive zone models, used together with the finite element method, are a viable tool to predict the strength of adhesive joints. The main objective of this study is to evaluate experimentally and numerically (by cohesive zone model) the mechanical performance of carbon-fiber reinforced polymer stepped-lap

Turbulent flat-plate boundary layer flows have been widely employed for numerical validation in the aero-optical field. In present study, the laminar-to-turbulent evolution induced by wavy roughness in high-Reynolds-number supersonic freestream is investigated using a numerical technique based on the fifth-order weighted compact nonlinear scheme (WCNS-E-5). The computational procedure and post-processing

A guidance problem for impact angle control applicable to a missile equipped with a passive seeker is investigated. The proposed guidance law based on the sliding mode control consists of the proportional navigation guidance term with a varying navigation constant and the additional biased term which is a function of the novel sliding surface. The guidance law directly uses the impact angle error but

Aircraft infrared signature is one of the most important properties for the military aircraft survivability. In terms of military aircraft, the exhaust system is the most significant infrared radiation source. The exhaust system accounts for more than 90% of the aircraft infrared radiation, and that the exhaust nozzle contributes the most significant infrared radiation of the whole radiation energy

Along with the increase in air traffic, the number of reported aviation events also increases. The authors have performed processing of the data included in the European Coordination Centre for Aviation Incident Reporting Systems (ECCAIRS) analyzing large aircraft reliability and safety of their operations considering events according to ICAO aviation occurrence categories. The airframe systems are

This article presents the numerical analysis of the aerodynamic impact of the fuselage on propeller performance in the pusher configuration and the propeller impact on the flow around the fuselage. The main aim of the presented investigation was to find the magnitude of the interaction between the propeller and the fuselage. This effect was evaluated based on the analysis of the change of the fuselage

Numerical simulation was carried out to study the influences of blade-bowing designs based on a highly loaded cascade with large turning angle, while the compound bowing design showed much lower endwall loss than the conventional design in this study. Generally, it showed that the increased turning angle would strengthen the adverse pressure gradient on the suction surface, so the side effect of negative

Classical approach to conceptual and preliminary design in aerospace sciences reaches limits. To go further and achieve better, competitive results’ use of optimization methods becomes mandatory. The trend is clearly visible in professional software for simulations equipped with optimization tools, which was not standard just decade ago. Many examples of multidisciplinary optimization were shown, especially

Focusing on the long-distance rapid cooperative rendezvous of two spacecraft under finite continuous thrust, this paper proposes a practical strategy for space operation using multiple specific-direction thrusts. Based on the orbital dynamic theory and Pontryagin’s maximum principle, the dynamic equations and optimal control equations for radial, circumferential, and normal thrust are determined. The

Technology of photovoltaic cells and lithium batteries is developing rapidly. As a result, more and more attempts are made to build solar high altitude long endurance airplanes. Unfortunately, data on altitude impact on photovoltaic cells and batteries performance are not easily available. Moreover, acquisition cost of cells is still high. As a result, high altitude long endurance airplanes design

Tailsitter unmanned aerial vehicles are utilized extensively nowadays since they merge advantages of both fixed-wing unmanned aerial vehicles and rotary-wing unmanned aerial vehicles. However, their attitude control suffers from unknown nonlinearities and disturbances due to the wide flight envelope. To solve the problems, a robust attitude controller based on a newly designed flying-wing tailsitter

Aerothermoelastic analysis of hypersonic vehicles is a complex multidisciplinary coupling problem. Thus, accurate modeling of varying disciplines with low computational cost is necessary. This work developed a tractable approach-based reduced-order modeling technology to solve the radiative thermal transfer problem in a hypersonic simulation. A method that combines proper orthogonal decomposition and

Aiming at the problem of missile attacking ground target in pitch plane, combined with a composite fast nonsingular terminal sliding mode, a new adaptive finite-time stable guidance law with attack angle constraint is designed based on the second-order sliding mode control. The improved extended state observer is used to estimate the uncertainties and compensate the control quantity, and the dynamic

An integrated celestial navigation scheme for spacecrafts based on an optical interferometer and an ultraviolet Earth sensor is presented in this paper. The optical interferometer is adopted to measure the change in inter-star angles due to stellar aberration, which provides information on the velocity of the spacecraft in the plane perpendicular to the direction of the observed star. In order to enhance

Recently, fluidic thrust vectoring control is popular for micro space launcher propulsion systems due to its several advantages, such as fast dynamic responsiveness, better control effectiveness, and no moving mechanical equipment. Counter-flow thrust vectoring control is an especially effective technique by utilizing less suction flow to control the mainstream deflection flexibly. In the current work

The request of even more stringent restrictions, regarding efficiency and environmental impact of industrial components, determines an optimized use of primary energy but also entails the design of more lightweight, smart and flexible devices, able to adapt their operation as a function of several different inputs. In this framework, the use of a fascinating class of metallic materials, called Shape

This paper presents the optimization of multi-element aerofoil for the LAR-3 Puffin -- STOL light transport aircraft concept proposal. Based on the geometry and aerodynamic characteristics of the well-known and proven in flight three-segment NACA 63A416 aerofoil, the authors explore the possibility of enhancing its high-lift performance by the movement of slot and flap position in extended (deployed)

This article investigates the design of a novel nonlinear robust adaptive control architecture to stabilize and control an airplane in the presence of left-wing damage. Damage effect is modeled by considering the sudden mass and inertia changes, center of gravity, and aerodynamic variations. The novel nonlinear control algorithm applies a state predictor as well as the error between the real damaged

This article presents L1 adaptive control scheme for vertical flight control of helicopter. Linear controller is designed as baseline controller to provide preliminary improvement in performance and robustness. Considering the existence of uncertainties and disturbances, we propose L1 adaptive controller with modified piecewise constant adaptation law to augment the baseline controllers. Further, the

Constructal T-shaped porous fins transfer better heat compared to the rectangular counterparts by improving the heat flow through the low resistive links. This type of fins can be used in aerospace engines which demand faster removal of heat without adding extra weight of the overall assembly. Here, in this study, three powerful nature-inspired metaheuristic algorithms such as particle swarm optimization

The failure of aeroengine rotor will cause a great threat to the flight safety. A new risk assessment model to assess the possibility and severity of failure of aeroengine rotor is presented addressing the problems that its failure samples are not sufficient and that early potential failures are not easy to recognize. The key point of this model is to determine the risk mechanism with diverse failures

A simple estimation method of momentum coefficient of synthetic jet actuator has been proposed. Flow separation over an airfoil can be suppressed sufficiently with the estimated momentum coefficient. At a certain angle of attack (AOA), momentum deficit of boundary layer at front of separation point can be quantified based on Bernoulli's theorem. The function of synthetic jet actuator is deemed to be

This paper aims to design a novel experimental platform with multiple testing possibilities on different individual performance parameters and different rotary propulsion systems. Three mechanic swingarms were constructed to separately and simultaneously test the rotor(s) and shroud, so that the interactions among different components can be involved. Based on it, measurements on the total thrust,

In fatigue test, the fatigue life of metal components is affected by many factors, such as test temperature, stress ratio and loading frequency. In order to study the influence of temperature on fatigue life of bolted joints, thermal stress and fast coefficient are introduced. A numerical method of fatigue crack initiation life is proposed based on Manson-Coffin strain fatigue formula. The crack initiation

Typically, the evaluation of nacelle drag in preliminary design is required to find an overall optimum engine cycle and flight trajectory. This work focuses on the drag characteristics of aero-engine nacelles with separate jet exhausts. The main body of analysis comes from 3D numerical simulations. A new near-field method to compute the post-exit force of a nacelle is presented and evaluated. The effects

A regional, turbofan-powered, 72-passenger, transport aircraft with very high aspect ratio truss-braced wings is developed with an affordable methodology from an existing 52 passenger, conventional twin-turboprop aircraft. At first, the ration behind the selection of the truss-braced wing configuration is discussed. Next, the methodologies for the sizing, weight, aerodynamics, performance, and cost

Stiffened panel as a kind of thin-walled component is widely used in aircraft. A novel stiffened panel manufacturing method has been proposed that the plate is bent into designed shape first with multi-point forming method and then milled into integral panel. However, in the bending process, springback is a great issue. In this paper, an analytical method is proposed to predict the springback of the

A new robust quaternion Kalman filter is developed for accurate alignment of stationary strapdown inertial navigation system. Most fine alignment algorithms have tried to estimate the biases of gyroscopes and accelerometers to reduce the errors of the alignment process. In stationary platforms, due to fixed inputs for sensors, the summation of various errors such as fixed bias, misalignment, scale

Critical inlet pressure (CIP) is a key parameter for ensuring the long life and steady operation of aircraft piston pumps. In the past, this parameter was determined through experimental methods that had drawbacks such as a long duration and narrow application range. To identify an alternate approach that can be substituted for the traditional approach, a numerical model for determining the CIP that

The structure and dynamic of the shock train in a mixing duct are investigated experimentally in a supersonic air breathing wind tunnel. High-speed schlieren technique and pressure measurements are utilized for the data acquisition. Nozzle clapboards are applied to separate the incoming flow into upper secondary flow, primary flow, and lower secondary flow. The Mach number of all incoming flows is

Several well-established best practices and reliable tools have been developed along the years to support aircraft conceptual and preliminary design. In this context, one of the most widely used tool is the Matching Chart (MC), a graphical representation of the different performance requirements (curves representing the thrust-to-weight ratio (T/W) requirement as function of the wing loading (W/S))

When modeling an aeroengine control system, effects of fuel metering unit are neglected or oversimplified, which most probably leads to unreliable simulation or experimental results. In order to well understand influences of fuel metering unit on performance of an aeroengine and to enrich the component-level model of a turboshaft aeroengine, a stepping motor controlled fuel metering unit is examined

Fuel efficiency improvement and harmful emissions reduction are the main motivations for the development of gas turbine combustors. Numerical computational fluid dynamics (CFD) simulations of these devices are usually computationally expensive since they imply a multi-scale problem. In this work, gaseous non-reactive unsteady Reynolds-Averaged Navier–Stokes and large eddy simulations of a gaseous-fueled

The present study presents a new nonlinear unsteady aerodynamic model to investigate the aeroelastic behavior of a self-sustained oscillating rigid airfoil. Here the unsteady Euler equations are considered simulating inviscid compressible transonic flow over an oscillating airfoil. In regard to providing boundedness criteria, a high-order technique based on a normalized variable diagram scheme has

This paper presents a method to use the Bezier curve to rapidly generate three-dimensional low-thrust trajectories, which can provide a suitable initial approximation to be used for more accurate trajectory optimal control tools. Two missions, from Earth to Mars and the asteroid Dionysus, are considered to evaluate the performance of the method. In order to verify the advantages of this method, it

The process of empirical models evaluation is at the core business of experimental flight-testing data analysis. Accurate and convenient flight-testing of helicopter engine(s) available power is crucial for predicting the total helicopter performance. Common practice in estimation of in-flight helicopter gas turbine engine power consists of a reduction of flight-test data into simplistic single-variable

In order to ensure flight safety, the stall test is one of the most important steps in the airworthiness certification phase of civil aircraft. The twisted-swept fan is one of the most important components of the high bypass ratio engine. The unsteady flow field of the fan rotor stall condition is obtained by numerical simulation. At the same time, the time series flow field data of the stall condition