Aerodynamic Concept Research Articles

Aerodynamics learning based on the development of an simplified conceptual glider design and flight testing

This study explores numerically and experimentally the conceptual design of a glider aircraft, focusing on achieving stable and efficient flight. The purpose of the work was the applied learning of aerodynamics for an undergraduate course in aerospace engineering. After research, simulations, and theoretical analyses, the project progressed to the practical stage, involving the construction and flight testing of the aircraft. This research included the identification of possible airfoils, consideration of Reynolds number limits and detailed analyses in XFLR5. Methods such as the Lifting Line Theorem and the Vortex Lattice Method were studied and applied in the project development.This approach underlines the study’s education aim - to demonstrate the practical application of theoretical knowledge. In summary, the design process, emphasizing the key milestones and challenges encountered during the manufacturing phase and the outcomes of the flight tests are discussed in detail. The project enabled the simulation and validation of aerodynamic concepts through construction, yielding flight results that were consistent with previous numerical predictions. This demonstrates that the proposed educational approach significantly enhances the practical application of theoretical knowledge in aerodynamics.

The aerodynamic behavioral study of canard plane with fan wing configuration

This study explores the optimization of the canard aerodynamic scheme by integrating wing-mounted propulsion systems to enhance efficiency. Key objectives include stability, controllability, and reducing frontal air resistance by employing an advanced aerodynamic scheme that effectively utilizes the wake filling phenomenon behind the wing when integrated with wing-mounted propulsion. The study emphasizes strategic design considerations for the wing, fuselage, and adjacent aerodynamic surfaces, which can enhance aerodynamic characteristics. Preserving the Coanda effect creates a low-pressure zone, improving overall efficiency. The paper underscores the importance of lightweight construction for safety and reliability. Numerical modeling underscores the need for physical experiments to validate results. Experimental simulations indicate possibilities for stable and controlled flight. Lightweight, reliable designs, and cutting-edge aerodynamic concepts offer prospects for improved efficiency and flight productivity.

The Progress and Application of Aerodynamics of the TOL Modes of Flying Vehicle

In general, flying vehicle represents for hybrid vehicle possesses fixed wing and the ability to fly based on aerodynamics principles. This paper will discuss the aerodynamic technology from the perspective of the application of flying vehicles. Specifically, the aerodynamic concepts such as lift, and wing design will be discussed. Moreover, the current state-of-art of the flying vehicle will be discussed. In addition, the state-of-art specific products will be introduced to help explain the current state-of-art. According to the analysis, the flying vehicle has great prospects. In the future, it is possible to eliminate traffic congestion and relieve pressure on the present metropolitan transportation network by applying this technology. Overall, these results shed light on the guiding the further exploration of flying vehicle in terms of aerodynamics.

Single-step deep reinforcement learning for two- and three-dimensional optimal shape design

This research gauges the capabilities of deep reinforcement learning (DRL) techniques for direct optimal shape design in computational fluid dynamics (CFD) systems. It uses policy based optimization, a single-step DRL algorithm intended for situations where the optimal policy to be learnt by a neural network does not depend on state. The numerical reward fed to the neural network is computed with an in-house stabilized finite elements environment combining variational multi-scale modeling of the governing equations, immerse volume method, and multi-component anisotropic mesh adaptation. Several cases are tackled in two and three dimensions, for which shapes with fixed camber line, angle of attack, and cross-sectional area are generated by varying a chord length and a symmetric thickness distribution (and possibly extruding in the off-body direction). At a zero incidence, the proposed DRL-CFD framework successfully reduces the drag of the equivalent cylinder (i.e., the cylinder of same cross-sectional area) by 48% at a Reynolds numbers in the range of a few hundreds. At an incidence of 30°, it increases the lift to drag ratio of the equivalent ellipse by 13% in two dimensions and 5% in three dimensions at a chord Reynolds numbers in the range of a few thousands. Although the low number of degrees of freedom inevitably constrains the range of attainable shapes, the optimal is systematically found to perform just as well as a conventional airfoil, despite DRL starting from the ground up and having no a priori knowledge of aerodynamic concepts. Such results showcase the potential of the method for black-box shape optimization of practically meaningful CFD systems. Since the resolution process is agnostic to details of the underlying fluid dynamics, they also pave the way for a general evolution of reference shape optimization strategies for fluid mechanics and any other domain where a relevant reward function can be defined.

A review of research into aerodynamic concepts for high speed trains in tunnels and open air and the air-tightness requirements for passenger comfort

India will soon have its first line with trains operating at internationally defined standards of high speed (exceeding 250 km/h). On the MAHSR (Mumbai-Ahmedabad High Speed Railway) corridor modern high speed trains will routinely operate at speeds as high as 200 mph (320 km/h). At high speed, trains are capable of generating significant aerodynamic effects including wind gusts and air pressure changes, which makes it necessary to address HSTs’ aerodynamics during the planning stage of high-speed rail (HSR) lines. The dynamic pressure tightness in train cars is also an important factor in the design of future railway tunnels, together with the medical health criterion and pressure comfort criteria. With increasing speed, the requirements of pressure tightness increases, which are explained and illustrated in this study. The current study is based on prior work done in the field of aerodynamic effects of HSTs, international standards, and design practice followed in existing HSR projects. Effort has been made to bring various studies in one place for ready reference. Parameters such as pressure comfort, optimized distance between center of track, wayside structural design, and tunnel cross-section requirements are explained. Based on the study and established relation by different authors, the pressure difference calculation is done for the MAHSR project for different scenarios, and passenger comfort was deduced. In this study, three major aspects of the aerodynamic pressure effect on the rolling stock and surroundings are examined, and each aspect is discussed distinctly: (1) open-air considerations: pressure effect on wayside structures, (2) open-air considerations: two trains crossing in the open field, and (3) open-air considerations: tunnel phenomenon: pressure wave effects on trains inside tunnels. The present study and a substantial portion of the existing knowledge base can be extrapolated for use in the future guidelines in India. This study examine the resultant pressures on wayside structures, the resultant pressures on adjacent trains, and pressure wave effects in tunnels (associated analyses were performed to determine the appropriate cross-sectional area of the tunnels), respectively. It includes basic aerodynamic concepts, influencing factors, measurement and calculation of pressure between trains, known and potential impacts, mitigations, standards, conclusions, and recommendations.

FIRST RESPONSE

A new hybrid emergency services First Responder vehicle incorporating a revolutionary aerodynamic concept and devised in conjunction with the Police is another step on the path to electrification and tackling climate change.

Flow adaptive aerodynamic probe for turbomachinery flows

In order to enable turbomachinery research to obtain data highly resolved in space and time, a novel flow adaptive aerodynamic probe concept has been developed and presented in this paper. The algorithm selects the measurement positions of the probe automatically and therefore provides higher measurement fidelity compared to traditional methods. The development of the adaptive algorithm has been done in several steps. First an automatic 1Dtraversing algorithm has been developed. The following steps dealt with the subject of a 2D adaptive flow concept development, whereas primarily visual programming language-computer package simulations of the new 2D algorithm have been done based on data from previous test series at the Turbomachinery Laboratory. The new 2D traversing algorithm is fully selfcontrolled and requires minimal input such as blade count and hub and tip diameters. Furthermore, areas of interest (e.g. secondary flows, wake) are detected automatically and higher measuring point resolutions are ensured in these regions. After the successful simulations, the intelligent 2D algorithm has been adapted to an object oriented programming environment used for automated data acquisition and reduction. An evaluation of the flow adaptive aerodynamic flow concept has been done on a pressure turbine facility by means of a steady pneumatic probe. The measurement results show that the new 2D algorithm has the potential to detect new flow phenomena. In contrast to traditional algorithms, which in case of a possible enhancement demand a knowledge of the position of interesting areas such as the wake and vortical structures before starting the measurement, the new algorithm detects the right areas and enhances the resolution fully self controlled in these areas. Furthermore, the new 2D flow adaptive probe concept shows a significant improvement regarding the needed time for one measurement.

A First Assessment of an Aerodynamic Barrier Layer for Filtering Airborne Hygroscopic Particles.

In this work, consideration is given to an aerodynamic concept to boost the filtration in face masks of airborne hygroscopic particles such as those caused by an infected person when coughs or sneezes. Nowadays, increasing the filtration efficiency of face masks implies either increasing the number of crisscrossing fiber layers or decreasing the equivalent hydraulic diameter of the pore, however, both measures are in clear detriment of its breathability. Here, a novel strategy is proposed in which the filtration of an airborne particle is boosted by increasing its diameter. We called properly this concept as the aerodynamic barrier layer. In this concept, a traditional crisscrossing fiber layer is replaced by a parallel rearranged of the fibers in the direction of the flow. This rearrangement will promote central lift forces which will push the particles toward the center of the channel where after clustering they will coalesce resulting in a bigger particle that can be now easily captured by a conventional fiber crisscrossing layer. Utilizing a simplified geometrical model, an expression for the required length of the aerodynamic barrier layer was derived. It is shown that an aerodynamic barrier layer with a length of only a few millimeters can aerodynamically focus water droplets around 1 μm-diameter and the penetration of airborne particles can be reduced up to 55%.

A CFD Tutorial in Julia: Introduction to Laminar Boundary-Layer Theory

Numerical simulations of laminar boundary-layer equations are used to investigate the origins of skin-friction drag, flow separation, and aerodynamic heating concepts in advanced undergraduate- and graduate-level fluid dynamics/aerodynamics courses. A boundary-layer is a thin layer of fluid near a solid surface, and viscous effects dominate it. Students must understand the modeling of flow physics and implement numerical methods to conduct successful simulations. Writing computer codes to solve equations numerically is a critical part of the simulation process. Julia is a new programming language that is designed to combine performance and productivity. It is dynamic and fast. However, it is crucial to understand the capabilities of a new programming language before attempting to use it in a new project. In this paper, fundamental flow problems such as Blasius, Hiemenz, Homann, and Falkner-Skan flow equations are derived from scratch and numerically solved using the Julia language. We used the finite difference scheme to discretize the governing equations, employed the Thomas algorithm to solve the resulting linear system, and compared the results with the published data. In addition, we released the Julia codes in GitHub to shorten the learning curve for new users and discussed the advantages of Julia over other programming languages. We found that the Julia language has significant advantages in productivity over other coding languages. Interested readers may access the Julia codes on our GitHub page.

Strength Analysis of Alternative Airframe Layouts of Regional Aircraft on the Basis of Automated Parametrical Models

This publication presents the results of complex parametrical strength investigations of typical wings for regional aircrafts obtained by means of the new version of the four-level algorithm (FLA) with the modified module responsible for the analysis of aerodynamic loading. This version of FLA, as well as a base one, is focused on significant decreasing time and labor input of a complex strength analysis of airframes by using simultaneously different principles of decomposition. The base version includes four-level decomposition of airframe and decomposition of strength tasks. The new one realizes additional decomposition of alternative variants of load cases during the process of determination of critical load cases. Such an algorithm is very suitable for strength analysis and designing airframes of regional aircrafts having a wide range of aerodynamic concepts. Results of validation of the new version of FLA for a high-aspect-ratio wing obtained in this work confirmed high performance of the algorithm in decreasing time and labor input of strength analysis of airframes at the preliminary stages of designing. During parametrical design investigation, some interesting results for strut-braced wings having high aspect ratios were obtained.

Aerodynamic study for the flow through cascade blades of gas turbine with vibration effect: a review

A research survey on aerodynamic with/without vibration effect and investigations for turbine components of gas turbine engines is presented. Experimental and numerically predicted results are presented from investigations undertaken over the past 70 years. The aerodynamics between the turbine blades is very important as it determines the overall system performance. The importance of aerodynamics is being in the pressure distribution above and below each airfoil, the locations of the vortices occurring, their number, distribution, direction, and shedding, and the determination of the regions of fluid separation from the wall that is directly related to the fluid velocity. Many ranges of vibration that affect different bodies were taken, and some of these ranges were small (10-200 Hz), and others had large ranges from 1.5 to 10 KHz. therefore the result evolution and shedding of vortices corresponding to the deformation in fluid structure depends on the Reynolds number and value of amplitude and frequency for vibration. The Mach number is a clear indicator to represent these characteristics. It also includes studying the theoretical methods used and simulations of the researchers’ aerodynamics, the accuracy of the results reached, the representation of the body contour and the diagrams for each of the pressure and Mach number, the pressure (Cp ) and lift (CL ) coefficients, and their amount of change occurring at each location of the airfoil. The importance of the above topics has motivated us to prepare a comprehensive review mostly of the aerodynamics of turbine blades and the effect of the vibration on the flow. The main concepts of aerodynamics, such as Cp and CL as well as vibration frequency are presented. It also highlights the performance of the turbine blades as a result of vibration

Tools and methodologies for box-wing aircraft conceptual aerodynamic design and aeromechanic analysis

A way to face the challenge of moving towards a new greener aviation is to exploit disruptive aircraft architectures; one of the most promising concept is the PrandtlPlane, a box-wing aircraft based on the Prandtl's studies on multiplane lifting systems. A box-wing designed accordingly the Prandtl “best wing system” minimizes the induced drag for given lift and span, and thus it has the potential to reduce fuel consumption and noxious emissions. For disruptive aerodynamic concepts, physic-based aerodynamic design is needed from the very early stages of the design process, because of the lack of available statistical data; this paper describes two different in-house developed aerodynamic design tools for the PrandtlPlane conceptual aerodynamic design: AEROSTATE, for the design of the box-wing lifting system in cruise condition, and THeLMA, aiming to define the layout of control surfaces and high lift devices. These two tools have been extensively used to explore the feasible space for the aerodynamic design of the box-wing architecture, aiming to define preliminary correlations between performance and design variables, and guidelines to properly initialize the design process. As a result, relevant correlations have been identified between the rear-front wing loading ratio and the performance in cruise condition, and for the rear-front flap deflections and the aeromechanic characteristics in low speed condition.

Design of a slotted, natural-laminar-flow airfoil for commercial transport applications

Slotted, natural-laminar-flow (SNLF) airfoils are a novel aerodynamic concept that enable significant performance improvements over conventional, single-element NLF airfoils. The S207, SNLF airfoil has been designed using requirements derived from a transonic, truss-braced wing commercial aircraft configuration. The airfoil is designed for a cruise Reynolds number of 13.2×106 and it exhibits a drag divergence Mach number exceeding 0.71. At these conditions, low drag is predicted to occur between lift coefficients of 0.40 and 0.79. The S207 airfoil exhibits a range-based figure of merit nearly triple that of a turbulent airfoil representative of modern commercial transport aircraft. Slotted configurations also have benefits for low-speed, high-lift conditions representative of approach. The S207 airfoil exhibits a low-speed, maximum lift coefficient in excess of 2.1, and is limited by compressibility effects around the leading edge. Incorporation of this airfoil onto a transonic, truss-braced wing configuration shows strong potential for meeting mid- and far-term goals for reducing aircraft fuel/energy consumption.

The green airliner that never was: aerodynamic theory, fuel-efficiency and the role of the British state in aviation technology in the mid-twentieth century.

Two aerodynamic concepts theorized in the early twentieth century - laminar-flow control and flying wings - offer the potential for more efficient aircraft. However, despite compelling advantages on paper and optimistic predictions, the fuel-saving benefits of these technologies have not yet been fully realized. This paper documents British work on these concepts, with a particular focus on laminar-flow control. Faced with an increasingly difficult funding context and a lack of a clear military rationale, these potentially significant advances in aircraft efficiency were stymied by a catch-22: the government was only prepared to provide financial support for the development of an operational prototype if operational performance had already been demonstrated. This case also highlights the challenges faced in the commercial uptake of radical aviation technologies, even when they appear to offer greater efficiency and environmental benefits.

Numerical Study of Airfoil Selection and Analysis of 3D Flow Phenomenon past Finite-Span Wings for Small UAVs

Small unmanned aerial vehicle (SUAV) is an unmanned aircraft vehicle (UAV) that flies at an altitude of lower than 1,100 m from the ground, has a maximum gross takeoff weight of 10 kg, and a flight speed of less than 50 m/s. One of the design factors for the small UAV design with a fixed-wing propeller is the airfoil selection. The selection of an airfoil profile using aerodynamic concepts leads to a performance coefficient that determines the selected airfoil’s sustainability and efficiency. The coefficients used are CL, CD, and CM. Numerical studies were carried out using Computational Fluid Dynamics using XFLR5 and ANSYS Fluent 19.1 software to evaluate airfoils in 2D and evaluate the phenomenon of induced drag on the wings in 3D. Airfoil selection was made on five types of airfoils: AH 83-150 Q, E399, E431, E715, and E662. The coefficients of CL, CD, and CM were obtained by varying α. 3D analysis of selected airfoil geometry with finite span. Simulation of steady conditions using Reynolds-Averaged-Navier-Stokes (RANS) in the Spalart-Allmaras turbulent model with variations of α = 0 ◦ , 8◦ , 12◦ , and 16◦ . The post-processor visualized the flow around the wing with pressure contours, velocity pathlines, and tip vortices. The analysis was carried out on the aerodynamic coefficients of CL, CD, CM, and CMr with α variation on the finite span wing. Based on the research, the results showed that the selected airfoil was E431, the aerodynamic performance of the CL, CD, CL/CD, CM, and CMr wings. In addition, information was also obtained regarding a decrease in the pressure difference between the upper surface and lower surface of the wing with an increasing span, 3D streamline, the extent of the contour of the vorticity magnitude, and a streamline on the wingtip on the upper surface and lower surface of the wing.

Bicycle aerodynamics: History, state-of-the-art and future perspectives

The importance of aerodynamics in cycling is not a recent discovery. Already in the late 1800s it was recognized as a main source of resistance in cycling. This knowledge was only rediscovered in the late 1970s and 1980s, when aerodynamic concepts were applied to bicycle equipment and cyclist positions, leading to new world hour records and Olympic medals. The renewed interest for cycling aerodynamics is significantly growing with the production of a vast literature, focused on increasing the comprehension of cycling aerodynamics and on improving the aerodynamics of bicycle equipment. Finding the connection between the different subfields of cycling aerodynamics and linking new research with past discoveries is crucial to efficiently drive future studies. Therefore, the present paper provides a comprehensive review of the history and the state-of-the-art in cycling aerodynamics, focusing on one of its main aspects: the bicycle. First, a short history of the bicycle is presented. Next, some cycling power models are outlined and assessment methods for aerodynamic drag are discussed, along with their main advantages and disadvantages. The core of this review paper addresses the components constituting the bicycle: frame and tubes, wheels, handlebar and other equipment. Finally, some future perspectives on bicycle aerodynamics are provided.

The aerodynamic development of the new Porsche Cayenne

With significantly enhanced performance, the third generation of the Porsche Cayenne is even more closely oriented towards the principles of sports cars. In addition to improving the driving-dynamic characteristics, the aim of the development was to lower the drag as a contribution towards the reduction of fuel consumption and emissions. Increasing performance and a simultaneous reduction of drag are conflicting objectives, which led to a number of aerodynamic challenges during the development of the new Cayenne. In addition to detailed aerodynamic optimisations, the solution for the new Cayenne consisted of an extended adaptive aerodynamic concept, which enables a compromise between fuel consumption, performance, and comfort depending on the driving condition. The first part of the concept comprises an extended air flap system that, for the first time, enables complete closing of all cooling air inlets in the front end. The second part of the concept is reserved for the top-of-the-range V8 Turbo model and consists of a multifunctional deployable roof spoiler that adapts to the aerodynamic characteristics of the relevant driving condition and features an air-brake function as a highlight.

From the Dawn of Aerodynamic Science to Modern Flow Control: a Brief Review

The first decade of the last century saw the emergence of aerodynamics as a distinct scientific discipline. Since then through the engagement of the creative and innovative minds, the branch of aerodynamic science has progressed in leaps and bounds. The present paper is an attempt to look at the development of this branch of science from its infant days to the present day of active flow control. If concerted efforts are made involving not only aero dynamists, but also scientists and engineers of other disciplines, many of the novel aerodynamic concepts can be exploited to solve some of the pressing problems facing humanity and make the world a better place to live in.

Aerodynamic Concept of the UAV in the Gyrodyne Configuration

Abstract The article presents an aerodynamic concept of UAV in the gyrodyne configuration, as a more efficient one than the currently used UAV airframe configuration applied for monitoring tasks of power lines and railway infrastructure. A sample task which is realised by conceptual gyrodyne based on monitoring aerial power lines was characterised and described. The assumed idea of UAV was shown in comparison to the currently used aircraft configuration presented in the introduction. Referring to momentum theory, hover efficiency of the multicopter and the helicopter was evaluated. In relation to the helicopter, an initial draft of the airframe conception accompanied by a description of advantages of the gyrodyne configuration was exposed. Problems related to the gyrodyne configuration were emphasised in the summary.

The Aerodynamic Concept of the Audi Q5

The Aerodynamic Concept of the Audi Q5