Air Vehicles Research Articles

Transmission Loss Characteristics of Dual Cavity Impedance Composite Mufflers for Non-Planar Wave Cavity Resonance

In conventional gasoline automobiles, the engine powers the air conditioning system and engine noise can somewhat mask the noise and vibration of the air conditioning system. In pure electric vehicles, however, the absence of an engine makes the air conditioning system’s noise more noticeable, concentrated in a limited frequency range at constant speeds. As a result, aerodynamic noise from the air conditioning system is a primary noise source in electric vehicles. Pipeline silencers are the main method for reducing this noise. The current silencer design uses plane wave acoustic theory but when cavity modal resonance occurs, the transmission loss error is relatively high. This article addresses the issue of non-planar wave cavity resonance, studying the cavity modal of a muffler using the finite element method to reveal the transmission loss under cavity mode resonance. A dual cavity expansion structure of an impedance composite muffler is proposed, with sound-absorbing materials placed in the cavity to enhance acoustic performance. The analysis of the transmission loss characteristics of the impedance composite muffler provides a theoretical basis for noise control in pure electric vehicle air conditioning systems.

Komunikasi Inovasi Jasa Raharja Cabang Riau Dalam Mengimplementasikan Pelayanan Santunan Online Korban Kecelakaan Di Kota Pekanbaru

Innovation communication is a way of conveying the discovery of new ideas to society so that social change occurs. A new innovation that is a solution to Jasa Raharja services which is caused by the high number of accidents in Pekanbaru City. In-person support services take a lot of time and take a long time, online updates make it easier for users of these support services. This research aims to analyze the communication innovation of raharja services in implementing online compensation services for accident victims in Pekanbaru city. This research uses qualitative research methods, with data collection techniques using interviews and analyzing the media used in the innovation diffusion process. As for determining research subjects, a purposive technique was used with five informants, then the data analysis technique used Miles and Huberman data analysis techniques which included data collection, data reduction, data presentation and conclusion drawing. This research uses Rogers and Shoemaker's theory of diffusion of innovation. This theory examines messages in the form of new ideas or thoughts, which cause social change.From the research results, this innovation communication has 4 stages, namely. In this research it can be concluded based on the results of the analysis using Roger's theory which has 4 points, This innovation distribution explains that the involvement of communicators provides information in the form of socialization in the form of a content that states information about how to claim or submit compensation from Jasa Raharja. A communicator does not only work alone, this communicator is the Head of Public Relations, Jasa Raharja, who works together with the compensation service staff to collaborate with the community to make it easier and more affordable. With new innovations, since 2009, compensation services for accident victims have gone from conventional forms to online services. This communication channel uses social media, namely in the form of Instagram and Tik Tok, then uses print media, television media and radio media. By implementing the Innovation Division, it has made progress, but of course there are still new innovations, of course this is influenced by factors that hinder the establishment of this innovation, one of which is awareness. The awareness of users or local people who use vehicles in traffic, whether land, sea or air, of course they do not have awareness.

Holographic visual cues for mission task elements

AbstractMission task elements (MTEs) are commonly used to evaluate the handling qualities (HQs) of rotorcraft. However, the traditional approach of physical ground courses faces challenges due to evolving rotorcraft designs and flight profiles. Infrastructure limitations and lack of flexibility for research pose significant obstacles, particularly for high-speed tasks. The emergence of new air vehicles, such as eVTOLs in the civil sector and future vertical lift configurations in the military domain, requires an adapted visual cueing process for previously unaddressed mission profiles. This paper proposes an innovative solution: an augmented reality (AR) system utilizing a head-mounted display to create virtual MTE courses called holographic visual cues (HVCs). A piloted simulation campaign performed at DLR’s AVES simulator compares the effectiveness of HVCs with dome projection-based visual cues, evaluating the performance of the AR system. The study investigated the impact of holographic visual cues on pilot handling qualities, workload ratings, and task performance, finding that although these cues typically do not significantly alter pilot ratings, individual responses varied, highlighting both the technology’s potential and the need for further refinement.

A numerical study on heat release characteristics on configuration of coolant passages in air vehicle motor

A numerical study on heat release characteristics on configuration of coolant passages in air vehicle motor

Minimum Distance and Minimum Time Optimal Path Planning With Bioinspired Machine Learning Algorithms for Faulty Unmanned Air Vehicles

Minimum Distance and Minimum Time Optimal Path Planning With Bioinspired Machine Learning Algorithms for Faulty Unmanned Air Vehicles

Study on aerodynamic noise of condensing fan of new energy vehicle air conditioner

Study on aerodynamic noise of condensing fan of new energy vehicle air conditioner

Oil Spill Mitigation with a Team of Heterogeneous Autonomous Vehicles

This paper presents the implementation of an innovative solution based on heterogeneous autonomous vehicles to tackle maritime pollution (in particular, oil spills). This solution is based on native microbial consortia with bioremediation capacity, and the adaptation of air and surface autonomous vehicles for in situ release of autochthonous microorganisms (bioaugmentation) and nutrients (biostimulation). By doing so, these systems can be applied as the first line of the response to pollution incidents from several origins that may occur inside ports, around industrial and extraction facilities, or in the open sea during transport activities in a fast, efficient, and low-cost way. The paper describes the work done in the development of a team of autonomous vehicles able to carry as payload, native organisms to naturally degrade oil spills (avoiding the introduction of additional chemical or biological additives), and the development of a multi-robot framework for efficient oil spill mitigation. Field tests have been performed in Portugal and Spain’s harbors, with a simulated oil spill, and the coordinate oil spill task between the autonomous surface vehicle (ASV) ROAZ and the unmanned aerial vehicle (UAV) STORK has been validated.

Research on insect-like long endurance hovering double-wing FMAV prototype

PurposeEndurance time is an important factor limiting the progress of flapping-wing aircraft. In this study, this paper developed a prototype of a double-wing flapping-wing micro air vehicle (FMAV) that mimics insect-scale flapping wing for flight. Besides, novel methods for optimal selection of motor, wing length and battery to achieve prolonged endurance are proposed. The purpose of this study is increasing the flight time of double-wing FMAV by optimizing the flapping mechanism, wings, power sources, and energy sources.Design/methodology/approachThe 20.4 g FMAV prototype with wingspan of 21.5 cm used an incomplete gear flapping wing mechanism. The motor parameters related to the lift-to-power ratio of the prototype were first identified and analyzed, then theoretical analysis was conducted to analyze the impact of wing length and flapping frequency on the lift-to-power ratio, followed by practical testing to validate the theoretical findings. After that, analysis and testing examined the impact of battery energy density and efficiency on endurance. Finally, the prototype’s endurance duration was calculated and tested.FindingsThe incomplete gear facilitated 180° symmetric flapping. The motor torque constant showed a positive correlation with the prototype’s lift-to-power ratio. It was also found that the prototype achieved the best lift-to-power ratio when using 100 mm wings.Originality/valueA gear-driven flapping mechanism was designed, capable of smoothly achieving 180° symmetric flapping. Besides, factors affecting long-duration flight – motor, wings and battery – were identified and a theoretical flight duration analysis method was developed. The experimental result proves that the FMAV could achieve the longest hovering time of 705 s, outperforming other existing research on double-wing FMAV for improving endurance.

Stability and Controller Research of Double-Wing FMAV System Based on Controllable Tail.

This study aimed to enhance the stability and response speed of a passive stabilized double-wing flapping micro air vehicle (FMAV) by implementing a feedback-controlled biomimetic tail. A model for flapping wings accurately calculated the lift force with only a 2.4% error compared to the experimental data. Experimental tests established the relationship between control torque and tail area, swing angle, and wing-tail spacing. A stability model for the double-wing FMAV was developed, incorporating stabilizing sails. Linearization of the hovering state facilitated the design of a simulation controller to improve response speed. By adjusting the feedback loops of velocity, angle, and angular velocity, the tail controller reduced the angle simulation response time from 4 s to 0.1 s and the velocity response time from 5.64 s to 0.1 s. In take-off experiments, a passive stabilized prototype with an adjustable tail angle exhibited enhanced flight stability compared to fixed tails, reducing standard deviation by 72.96% at a 0° take-off angle and 56.85% at a 5° take-off angle. The control axis standard deviation decreased by 38.06% compared to the passive stability axis, confirming the effectiveness of the designed tail angle controller in reducing angular deflection and improving flight stability.

New Data-Driven Models of Mass Flow Rate and Isentropic Efficiency of Dynamic Compressors

Dynamic compressors are widely used in many industrial sectors, such as air, land, and marine vehicle engines, aircraft environmental control systems (ECS), air-conditioning and refrigeration, gas turbines, gas compression and injection, etc. The data-driven formulas of mass flow rate and isentropic efficiency of dynamic compressors are required for the design, energy analysis, performance simulation, and control- and/or diagnosis-oriented dynamic simulation of such compressors and the related systems. This work develops data-driven models for predicting the performance of dynamic compressors, including empirical models for mass flow rate and isentropic efficiency, which have high prediction accuracy and broad application range. The performance maps of two multi-stage axial compressors of an aero engine and a centrifugal compressor of an aircraft ECS were chosen for evaluation of the existing empirical formulas and testing of the new models. There are 16 empirical models of mass flow rate and 14 empirical models of isentropic efficiency evaluated, and the results show that it is necessary to develop highly accurate empirical formulas both for mass flow rate and isentropic efficiency. With the data-driven method, two empirical models for mass flow rate and one for isentropic efficiency are developed. They are in general form, with some terms removable to make them simple while enhancing their applicability and prediction accuracy. The new models have much higher prediction accuracy than the best existing counterparts. The new mass flow rate models predict for the three compressors a mean absolute relative deviation (MAD) not greater than 1.3%, while the best existing models all have MAD > 2.0%. The new efficiency model predicts for the three compressors an MAD of 1.0%, 0.4%, and 1.9%, respectively, while the best existing model predicts for the three compressors an MAD of 1.8%, 0.8%, and 3.2%, respectively.

Piecewise-linear car-following with heterogeneous agent dynamics: Consensus and emerging collective behaviors

The dynamics of multiples agents with heterogeneous behaviors, and under constraints on speed limits and safe separation distances are generally nonlinear and complex. A deep comprehension of such dynamics, in particular the derivation of eventual emerging collective behaviors would open the doors for a deep understanding of the physics of such systems, and then for the optimization and optimal control of the agent dynamics and of the macroscopic behaviors, with possible interesting applications in multiple fields, such as autonomous driving, unmanned air vehicles, etc. We present in this article an extension of an existing car-following model where a number of agents move on a ring without passing and with constraints on agents’ speed limits and safe separation. The extension includes the possibility to consider heterogeneous behaviors of the agents, contrary to the existing model which is limited to homogeneous behaviors. We analyze the agent dynamics and characterize the conditions under which stationary regimes exist. Moreover, we analytically derive the asymptotic characteristics of the system. In particular, we analytically derive the average asymptotic agent-speed as a function of the total agent-density in the ring, and of the different agent-behaviors considered. Furthermore, we show that collective behaviors emerge and characterize them under different conditions.

Over a decade of UAV incidents: A human factors analysis of causal factors

This analysis examined systemic causes of Uncrewed Air Vehicle (UAV) accidents identifying operator, environmental, supervisory, and organisational factors through the use of the Human Factors Analysis and Classification System (HFACS). HFACS is a system-based analysis method for investigating the causal factors associated with accidents and incidents and has previously been used to reliably and systematically identify active and latent failures associated with both military and general aviation accidents. Whilst HFACS has previously been applied to UAV accidents, the last known application was conducted in 2014. Using reports retrieved from nine accident investigation organisations’ databases, causal factors were coded against unsafe acts, preconditions, and failures at the supervisory, organisational, and environmental levels. Causal factors were assessed on 77 medium or large UAV mishaps/accidents that occurred over a 12-year period up to 2024. 42 mishap reports were deemed to involve a human factor as a causal factor. A large proportion of the mishaps contained factors attributed to Decision Errors at level 1 (Unsafe Acts) which was found to be associated with both the Technological Environment and Adverse Mental State at level 2 (Pre-conditions). Causal factors were identified at each of the other 3 levels (Supervisory, Organisational and External) with a number of emergent associations between causal factors. These data provide support for the identification and development of interventions aimed at improving the safety of organisations and advice of regulators for Uncrewed Air Systems.

Study of Low-Temperature Energy Consumption Optimization of Battery Electric Vehicle Air Conditioning Systems Considering Blower Efficiency

Battery electric vehicle (BEV) air conditioning systems often use positive temperature coefficient (PTC) heaters to heat the passenger compartment. The heating process consumes a lot of energy in low-temperature environments, which seriously affects the driving range and user experience. This study aims to reduce the low-temperature energy consumption of the air conditioning system and improve energy efficiency through an innovative optimization method. In this study, the energy consumption composition of the air conditioning system was analyzed, and the goal of minimizing the sum of the total power consumption of the PTC heater and the blower was determined, while the efficiency characteristic of the blower was considered at the same time. The relationship between the average temperature of the passenger compartment measurement points and the PTC power and airflow rate was studied by combining experiments and numerical simulations, and the alternative operating conditions that met the temperature requirement were determined. On this basis, the total power consumption of the air conditioning system was analyzed and optimized. The results show that PTC power, airflow rate, and blower efficiency all have an important influence on the total power consumption of the air conditioning system. The optimized scheme could reduce the theoretical total power from 1315.32 W of the original scheme to 1246.83 W, and the actual total power from 1350.05 W of the original scheme to 1326.56 W, with reductions of 5.21% and 1.74%, respectively. The low-temperature energy consumption optimization method for the BEV air conditioning systems proposed in this study is instructive for the selection of blowers and the design of control strategies for air conditioning systems.

Off-design analysis of the inverted Brayton cycle engine

PurposeThe purpose of this study is to perform an off-design analysis of the inverted Brayton cycle engine.Design/methodology/approachThe off-design analysis equations of the inverted Brayton cycle engine were first derived in this study and the control parameters of the inverted Brayton cycle engine were first determined and investigated.FindingsIt is observed that by controlling the total temperature decrease in cooling section, it is possible to adapt the engine for low specific fuel consumption working conditions or high thrust working conditions. Specific fuel consumption is reduced by 27.1 % by stopping cooling in the cooling section and thrust is increased by 27.6 % by working with full load of the cooling section (500 K temperature decrease in cooling section). It is observed that thrust depending on the flight Mach number increases with an increase in flight Mach number and reaches a peak value at 5.21 flight Mach number and reduces by 80.8 % at 6 flight Mach number relative to the peak value. The specific fuel consumption increases rapidly as the Mach number increases, and the specific fuel consumption is 49.0 g/[kN.s] at Mach 1, reaches 70.4 g/[kN.s] at Mach 5 and increases to 412 g/[kN.s] at Mach 6. The specific fuel consumption increases from 68.1 to 73.0 g/(kN.s) and the thrust decreases from 16.5 to 13.3 kN as the total preburner exit temperature increases from 1,500 to 2,000 K. Specific fuel consumption decreases from 83.1 to 64.8 g/(kN.s) and thrust increases from 4.60 to 11.08 kN depending on afterburner exit total temperature increase from 1,800 to 2,500 K.Research limitations/implicationsThe cooling section reduces total temperature of the gas flow to lower values to increase the compressor total pressure ratio. The compressor increases the total pressure of the gas flow to the optimum total pressure ratios to increase the nozzle exit Mach number and gain more thrust. The afterburner increases the total temperature of the gas flow to increase the sound speed in the nozzle exit to increase thrust. The nozzle expands the gas flow to reduce the static pressure of the gas flow to near the optimum value, atmosphere pressure, to increase thrust and reduce specific fuel consumption.Practical implicationsHypersonic and supersonic air vehicles can use the current engine model for the its own propulsion systems.Social implicationsAfter first heavier than air flight, aero engines was designed for only used for aero vehicle. Internal combustion engines were used for propelled propeller aircraft at the first term of aircraft. However, propeller-propelled aircrafts are not sufficient to increase aircraft velocity to supersonic Mach numbers due to the shock losses of propeller, so the supersonic era was only introduced by revolution in propulsion systems with new concept. A jet engine was developed to be candidate for supersonic flight.Originality/valueOff-design analysis equations of an inverted Brayton cycle engine were first derived in this study. Furthermore, the control parameters of the inverted Brayton cycle engine were first determined and investigated in this paper.

A new method for inspection and detection of typical defects of protective facilities in existing railways and its application

Due to the frequent occurrence of defects of slope protection facilities on existing lines causing the potential major geological hazards (e.g., landslides), it is necessary to promote the inspection and detection efficiency of various defects of slope protection facilities for carrying out early warning and evaluation, as well as, putting forward relevant control measures for slope disasters. Based on the case studies of hundreds of protective facilities on the existing railway line, the typical defect types, characteristics and specific causes of retaining wall, slope protection, anti-slide pile and anchorage engineering structure are firstly determined. Subsequently, a new comprehensive method combining unmanned air vehicle (UAV) and intelligent detection of portable radar (IDPR) are proposed. Among of them, UAV can effective and efficient identify the defect situations of slope protection facilities, and the water accumulation and cracks of retaining wall through performing a periodic inspection of the surrounding environment of protective facilities. In addition, IDPR can detect the filling situations behind the protective facilities to prevent the collapse danger. Through comparison with the drilling core results of tested areas, it is found that the detection results of the IDPR are more reliable and accurate, which is worthy of popularization and application in the field.

Pneumatic Vehicle: Prototype that Function on Pneumatic System

Believe it or not, using compressed air to power vehicles is a real thing. This innovative concept, known as the "pneumatic vehicle," has captured the interest of researchers worldwide. It is hailed for its zero emissions and suitability for city driving. MDI is a company that holds the international patents for this technology. While it may appear to be an eco-friendly solution, the energy needed to compress air must be factored in when assessing its overall efficiency. Despite this, pneumatic vehicles offer promise in reducing urban air pollution over time. These vehicles, also referred to as air-powered or compressed air vehicles, represent a cutting-edge mode of transportation.

Tutorial Review of Indirect Wind Estimation Methods Using Small Uncrewed Air Vehicles

Tutorial Review of Indirect Wind Estimation Methods Using Small Uncrewed Air Vehicles

Implementation of a toolbox for the generation of flight profiles for use in simulator studies

Motion sickness is a phenomenon which can produce various symptoms in affected individuals. During development of new aircraft types and cabin layouts, it is important to consider this phenomenon early on, to reduce resulting effects. For research on this topic, German Aerospace Center uses the simulator environment Air Vehicle Simulator together with the Advanced Future Cabin. The Air Vehicle Simulator is a full flight simulator with an interchangeable cockpit module. One of those modules is the Advanced Future Cabin, a realistic replica of an aircraft cabin. Good standardization of the test conditions is required to ensure objectivity and reliability of motion sickness studies in this simulator environment. A specialized software infrastructure is used to replay pre-recorded flight profiles, which are then reproduced by the simulator’s motion, visual and audio systems. Using this replay approach, complete flight profiles can be reproduced very well. However, when parts of the flight profile need exact reproduction within a flight profile or across multiple flight profiles, the approach to record pilot-in-the-loop simulation sessions becomes problematic, as flying the exact same twice is almost impossible. As an improved approach, a toolbox has been implemented, which automates the generation of flight profiles, enabling easier and more precise research on motion sickness in the simulator. The toolbox replaces the pilot-in-the-loop simulation with an automated control of the underlying aircraft simulation model. This leads to greatly improved accuracy of inputs to the simulation model and thus very good reproducibility even of flight profile segments. In this manuscript, details of the toolbox implementation and its validation are discussed.

Ramification of Hall effects in a non-Newtonian model past an inclined microchannel with slip and convective boundary conditions

Abstract Many applications, including micro air vehicles, automotive, aerospace, refrigeration, mechanical–electromechanical systems, electronic device cooling, and micro heat exchanger systems, can be used to determine the heat flow in microchannels. Regarding engineering applications, heat flow optimization discusses the role of entropy production minimization. Therefore, this work explores new facets of entropy production in fully developed Carreau fluid heat transport in an inclined microchannel considering exponential space/temperature dependence, radiative heat flux, and Joule heating. The Carreau fluid model’s rheological properties are taken into account. Additionally, the influence of Hall slip velocity and convective boundary conditions is considered. Using appropriate transformation constraints, the governing equations are transformed into a system of ordinary differential equations, which are then numerically solved using the fourth- and fifth-order Runge–Kutta–Fehlberg method. Graphs illustrate a significant discussion of physical parameters on production of entropy, Bejan number, thermal field, and velocity. Our findings established that there is a dual impact of entropy generation for the exponential space/temperature-dependent, radiation parameter, Hall parameter, Weissenberg number, and velocity slip parameter. The Bejan number decreased with the Hall current and the Weissenberg number, and it enhanced with exponential space/temperature dependent. The convection constraint maximizes the entropy at the channel walls. The results are compared with exact solutions, which show excellent agreement.

3D wave dispersion analysis of graphene platelet-reinforced ultra-stiff double functionally graded nanocomposite sandwich plates with metamaterial honeycomb core layer

This research addresses the three-dimensional thermomechanical wave propagation behavior in sandwich composite nanoplates with a metamaterial honeycomb core layer and double functionally graded (FG) ultra-stiff surface layers. Due to its potential for high-temperature applications, pure nickel (Ni) is preferred for the honeycomb core layer, and an Al2O3/Ni ceramic-metal matrix is preferred for the surface layers. The functional distribution of graphene platelets (GPLs) in three different patterns, Type-U, Type-X, and Type-O, in the metal-ceramic matrix with a power law distribution provides double-FG properties to the surface layers. The mechanical and thermal material characteristics of the core and surface layers, as well as the reinforcing GPLs, are temperature-dependent. The pattern of temperature variation over the plate thickness is considered to be nonlinear. The sandwich nanoplate’s motion equations are obtained by combining the sinusoidal higher-order shear deformation theory (SHSDT) with nonlocal integral elasticity and strain gradient elasticity theories. The wave equations are established by using Hamilton’s principle. Parametric simulations and graphical representations are performed to analyze the effects of honeycomb size variables, wave number, the power law index, the GPL distribution pattern, the GPL weight ratio, and the temperature rise on three-dimensional wave propagation in an ultra-stiff sandwich plate. The results of the analysis reveal that the 3D wave propagation of the sandwich nanoplate can be significantly modified or tuned depending on the desired parameters and conditions. Thus, the proposed sandwich structure is expected to provide essential contributions to radar/sonar stealth applications in air, space, and submarine vehicles in high or low-temperature environments, protection of microelectromechanical devices from high noise and vibration, soft robotics applications, and wearable health and protective equipment applications.