The air-breathing hypersonic vehicle (AHV) holds the potential to revolutionize global travel, enabling rapid transportation to low-Earth orbit and even space within the next few decades. This study focuses on investigating the nonlinear dynamic simulation, trim, and stability analysis of a three-degrees-of-freedom (3DOF) longitudinal model of a generic AHV for variable control surface deflection,and. A simulation is developed to analyze the burstiness of the AHV’s nonlinear longitudinal behavior, considering the complete flight envelope across a wide range of Mach numbers, from= 0 to 24, for selected stable. The presented simulation assesses trim analysis and explores the dynamic stability of the AHV through its flight envelope and bifurcation method analysis is carried out to gain insight and validate the dynamic stability using eigen value approach.

Singh, Ritesh, Prakash, Om, Joshi, Sudhir, Sharma, Rakesh Chandmal

Designing an Uncrewed Aircraft Systems Control Model for an Air-to-Ground Collaborative System

01-17-02-0014

02/19/2024

Abstract In autonomous technology, uncrewed aircraft systems have already become the preferred platform for the research and development of flight control systems. Although they are subjected to following and satisfying complicated scenarios of control stations, this high dependency on a specific control framework limits them in their application process and reduces the flight self-organizing network. In this article, we present a developed multilayer control system protocol with the additional supportive manned aircraft layer (Tender). The novelty of the introduced model is that uncrewed aircraft systems are monitored and navigated by the tender, and then based on the suggested scheme, data flows are controlled and transferred across the network by the developed cloud–robotics approach in the ground station layer. Therefore, it has been tried to design a semi-autonomous control network to gather data that combines human observation and the automotive nature of uncrewed aircraft

Millar, Richard C., Laliberté, Jeremy, Mahmoodi, Armin, Hashemi, Leila, Meyer, Robert Walter

Computational Investigation of a Flexible Airframe Taxiing Over an Uneven Runway for Aircraft Vibration Testing

01-17-02-0011

12/15/2023

Ground vibration testing (GVT) is an important phase of the development, or the structural modification of an aircraft program. The modes of vibration and their associated parameters extracted from the GVT are used to modify the structural model of the aircraft to make more reliable dynamics predictions to satisfy certification authorities. Due to the high cost and the extensive preparations for such tests, a new method of vibration testing called taxi vibration testing (TVT) rooted in operational modal analysis (OMA) was recently proposed and investigated by the German Institute for Aerospace Research (DLR) as alternative to conventional GVT. In this investigation, a computational framework based on fully coupled flexible multibody dynamics for TVT is presented to further investigate the applicability of the TVT to flexible airframes. The time domain decomposition (TDD) method for OMA was used to postprocess the response of the airframe during a TVT. The framework was then used to

Al-bess, Lohay, Khouli, Fidel

Nonlinear Observer for Estimating Gravity Vector and Flight Path Angles of a High-Performance Aircraft

01-17-01-0007

08/14/2023

This paper proposes a nonlinear observer for the estimation of gravity vector and angles with respect to velocity vector (flight path angle, bank angle) of a high-performance aircraft. The technique is computationally simpler than the extended Kalman filter (EKF) and hence is suitable for onboard implementations when the digital flight control computer (DFCC) has computational burdens. Flight test data of a highly maneuvering flight such as wind-up turns and full rolls have been used to validate the technique.

Chandrasekaran, Kamali, Jain, Shikha

NOISE ANALYSIS IN DIFFERENT FLAPPING MECHANISMS FOR EFFICIENT FLYING

2025-01-002105/05/2023

In a variety of intricate and dynamic settings, flying animals, like birds and insects [5],[8], can fly with efficiency. Despite being stated as "unsteady aerodynamics", the flapping of birds was the first biological mechanism that inspired humans to fly. Though flapping wings is the most efficient way of flying, the main hindrance is its unsteady nature of gaining a counter-lift for each flap. Compared to current manned aerial vehicles, flying animals fly at a lower Reynolds number. A fluid's ratio of viscous to inertial forces is represented by the Reynolds number, which is a dimensionless quantity. The ratio of forward speed to flapping frequency is represented by the dimensionless number known as the decreased frequency. Yet, by utilizing these beneficial animal flying traits, unmanned aerial vehicles (UAVs) functioning in the low Reynolds number zone can be enhanced. The primary aim of this project is to analyze two flapping mechanisms: straight continuous wing and swept & bent

Keshav Kumar, A B, Patric, Alan, R, Asad Ahmed, Srinivasan, Venkatramanan, Mani, Midhun, Jayachandran, Rohith

Sonic Boom Velocity and Altitude Sensitivity Analysis of a Hypersonic Aircraft Concept

2025-01-003505/05/2023

During the last decades there has been a renewed interest in the development of a new generation of supersonic aircraft for civil purposes. However, the noise generated by supersonic aircraft during supersonic flight, commonly referred to as "sonic boom", is still creates annoyance to community on the ground that prohibits supersonic overland flight. To prepare for the advent of a new generation of supersonic aircraft and to define new regulations for them, an increasing number of sonic boom studies is being published. This paper presents numerical simulations of the sonic boom of a hypersonic (Mach 5) aircraft concept. The study describes a sensitivity analysis of the two parameters velocity and altitude. The extensive simulations characterize the sonic boom carpet of the aircraft for different speeds between Mach 1.2 and Mach 5.0, and for two altitudes of 11.3 km and 28.0 km above sea level. The simulation approach is divided into two main regions. This approach is well understood

Graziani, Samuele, Jäschke, Jacob Jens, Viola, Nicole, Gollnick, Volker

Research on Clustered Multi-channel Active Noise Control System in Car

2025-01-001605/05/2023

In order to solve the problem of intermittent engine intervention during charging and discharging of diesel-electric hybrid vehicles, this paper proposes a semi-coupled cluster control strategy with better comprehensive performance based on the traditional multi-channel Active Noise Control (ANC) system and the advantages of centralized control strategy and decentralized control strategy. Compared with the centralized control strategy, the computational cost of the cluster control strategy is reduced by about 50%, and the noise attenuation performance is comparable to that of the centralized control strategy. Compared with the decentralized control strategy, the stability is obviously better, and the noise reduction effect is outstanding. Based on the MATLAB simulation platform, a variety of cluster control strategies and traditional control strategies in the vehicle are compared and analyzed, and the road test experiments of a range-extended electric vehicle are carried out under its

deng, huiping, Lu, Chihua, Liu, Zhien, Ji, Huijun, Dou, Sirui, Sun, Menglei

Indirect blocked force measurement of a hydraulic power pack for structural vibration transmission into an airframe

2025-01-005205/05/2023

Centralization of electrically driven hydraulic power packs into the body of aircraft have increased the attention on the noise and vibration characteristics of the system. A hydraulic power pack consists of a pump coupled to an electrical motor, accumulator, reservoir, and associated filter manifolds. In previous studies, the characteristics of the radiated acoustic noise and fluid borne noise were studied. In this paper, we focus on the structure borne forces generated by the hydraulic pump characterized through blocked force measurements. The blocked force of the pump was determined experimentally using an indirect measurement method. The indirect method required operation with part under test fixed to an instrumented receiver structure. Measured operational accelerations on the receiver plate were used in conjunction with transfer function measurements to predict the blocked forces. Blocked forces were validated by comparing directly measured accelerations to predicted

Smither, Matthew, Tuyls, Zachary, Patel, Pratik, Yan, Xin, Herrin, David

Noise Reduction in High-Speed Sonic Under expanded jets using Slanted Perforated Tabs

2025-01-003205/05/2023

Studies on High-Speed Jet control is of prime importance to aerospace as well as related industries. Proper mixing of Jet of a fuel with the surrounding air is indispensable in the combustion chamber of a propulsive system, this contributes to the need of enhancing mixing of Jet with ambient air. The noise radiated by a jet engine is also a major problem for many cities around the world and this method also reduces the Jet associated noise which is of immense environmental concern for transport aircrafts. The High-speed Jet control is achieved by using two different methods. They are active Control method and passive control method. In active control method, the idea is to introduce stream wise vortices into the mixing layer of the jet. Passive control of the jet can be achieved by adding geometrical modifications. The present study deals with an innovative passive control of jet using slanted perforated tabs. which focuses on the method of changing the structures in turbulent free

R, Asad Ahmed, SUBRAMANIAN, THANIGAIARASU

Sonic Boom propagation using high and low-fidelity methods

2025-01-003405/05/2023

A bottle neck to the introduction of civil supersonic aircraft is represented by the noise produced by shock waves during the cruise flight, the so-called "sonic boom". Authorities prohibit supersonic flight over land due to the exceeding noise levels produced by sonic boom. This work deals with a comprehensive methodology for assessing the aircraft sonic-boom signature at ground level starting from an accurate estimation of the near-field pressure signature caused by shock-wave pressure. High fidelity computational fluid dynamics (CFD) is typically used to calculate near-field sonic booms, whereas proper models are used for propagating at long distances, since CFD becomes computationally demanding as propagation distances exceed 10 km. The present study focuses on assessing a low-fidelity technique (e.g. Whitam's equation) against the direct application of a high-fidelity CFD method for sonic boom propagation at a medium distance. The former propagates the pressure signature through

Glorioso, Antimo, Fasulo, Giovanni, Petrosino, Francesco, Barbarino, Mattia

An Aerodynamic Equation of State—Part I: Introduction and Aerospace Applications - QA Test Tatsiana

01-17-01-0001

04/19/2023

Abstract In subsonic aircraft design, the aerodynamic performance of aircraft is compared meaningfully at a system level by evaluating their range and endurance, but cannot do so at an aerodynamic level when using lift and drag coefficients, CL and CD , as these often result in misleading results for different wing reference areas. This Part I of the article (i) illustrates these shortcomings, (ii) introduces a dimensionless number quantifying the induced drag of aircraft, and (iii) proposes an aerodynamic equation of state for lift, drag, and induced drag and applies it to evaluate the aerodynamics of the canard aircraft, the dual rotors of the hovering Ingenuity Mars helicopter, and the composite lifting system (wing plus cylinders in Magnus effect) of a YOV-10 Bronco. Part II of this article applies this aerodynamic equation of state to the flapping flight of hovering and forward-flying insects. Part III applies the aerodynamic equation of state to some well-trodden cases in fluid

Burgers, Phillip

An Aerodynamic Equation of State—Part I: Introduction and Aerospace Applications - QA Test Tatsiana

01-17-01-0001-TEST-REC04/19/2023

Burgers, Phillip

An Aerodynamic Equation of State—Part I: Introduction and Aerospace Applications

01-17-01-0001

04/19/2023

In subsonic aircraft design, the aerodynamic performance of aircraft is compared meaningfullyby evaluating their range and endurance, but cannot do so atwhen using lift and drag coefficients,and, as these often result in misleading results for different wing reference areas. This Part I of the article (i) illustrates these shortcomings, (ii) introduces a dimensionless number quantifying the induced drag of aircraft, and (iii) proposes anfor lift, drag, and induced drag and applies it to evaluate the aerodynamics of the canard aircraft, the dual rotors of the hoveringMars helicopter, and the composite lifting system (wing plus cylinders in Magnus effect) of a YOV-10. Part II of this article applies this aerodynamic equation of state to the flapping flight of hovering and forward-flying insects. Part III applies the aerodynamic equation of state to some well-trodden cases in fluid mechanics found in fluid-mechanics textbooks.

Burgers, Phillip

Aerodynamics of Landing Maneuvering of an Unmanned Aerial Vehicle in Close Proximity to a Ground Vehicle

2023-01-0118

04/11/2023

Autonomous takeoff and landing maneuvers of an unmanned aerial vehicle (UAV) from/on a moving ground vehicle (GV) have been an area of active research for the past several years. For military missions requiring repeated flight operations of the UAV, precise landing ability is important for autonomous docking into a recharging station, since such stations are often mounted on a ground vehicle. The development of precise and efficient control algorithms for this autonomous maneuvering has two key challenges; one is related to flight aerodynamics and the other is related to a precise detection of the landing zone. The aerodynamic challenges include understanding the complex interaction of the flows over the UAV and GV, potential ground effects at the proximity of the landing surface, and the impact of the variations in the surrounding wind flow and ambient conditions. While a large body of work in this area can be found on the control aspect of the UAV landing and takeoff maneuvers

Uddin, Mesbah, Nichols, Spencer, Hahn, Cortney, Misar, Adit, Desai, Shishir, Tison, Nathan, Korivi, Vamshi

HANDBOOK OF HYDRAULIC METRIC CALCULATIONS

AIR1657 (Current)04/05/2023

SI and other metric units related to aerospace hydraulics are summarized. Conversion of English units is provided as required. Fundamental fluid properties and physical laws governing fluid motion and pressure are described in SI units. Examples of application to typical aerospace hydraulic system components are worked out. Thermodynamic processes are excluded from the scope of this report.

A-6A2 Military Aircraft Committee

Infrared Signature of Fixed and Variable Area C-D Nozzle of Aircraft Engine

01-16-02-0011

01/02/2023

The use of converging-diverging (C-D) variable area nozzle (VAN) in military aeroengines is now common, as it can give optimal expansion and control over engine back pressure, for a wide range of engine operations. At higher main combustion temperatures (desired for supercruise), an increase in the nozzle expansion ratio is needed for optimum performance. But changes in the nozzle throat and exit areas affect the visibility of engine hot parts as the diverging section of the nozzle is visible for a full range of view angle from the rear aspect. The solid angle subtended by engine hot parts varies with change in visibility, which affects the aircraft infrared (IR) signature from the rear aspect. This study compares the performances of fixed and variable area nozzles (FAN and VAN) in terms of engine thrust and IR signature of the engine exhaust system in the boresight for the same increase in combustion temperature. This study is performed for two cases: (i) variable throat area and

Baranwal, Nidhi, Mahulikar, Shripad P.