Aerodynamic Integration Research Articles

RMSE POWER COEFFICIENT OF WIND TURBINES WITH INVERSE TOQUE-SPEED CONTROL

The Blade Element Momentum (BEM) method stands out among various turbine modelling techniques due to its integration of airfoil aerodynamics with momentum theory, allowing detailed force calculations on blade elements. While traditional methods like BEM and Wake Models are efficient for initial turbine design, advancements in computational power have enabled the use of Computational Fluid Dynamics (CFD) for more accurate simulations. Although these models are precise, they are computationally intensive, leading to the continued use of simpler empirical methods, such as the static power coefficient approach, in power system studies. Future research aims to validate and implement dynamic estimation models to account for wind variability and turbine control dynamics. Traditional constant torque-speed control strategies maintain a constant generator speed by using a fixed electromagnetic torque command and adjusting the pitch angle when wind speed exceeds the rated value. However, if the pitch control does not respond quickly enough, rotor acceleration can occur, leading to increased power beyond the generator’s rating. To mitigate this, the pitch control mechanism must react promptly to adjust the turbine's torque profile, ensuring convergence to the rated operating point and avoiding prolonged generator overload. To reduce the burden on the pitch-control system, an inverse torque-speed control approach is proposed, where the electromagnetic torque is dynamically adjusted based on real-time rotor speed data. This method aims to achieve rated power operation with improved responsiveness and reduced stress on the pitch-control mechanism.

Scarab Beetle‐Inspired Embodied‐Energy Membranous‐Wing Robot with Flapping‐Collision Piezo‐Mechanoreception and Mobile Environmental Monitoring

AbstractThe mechanoreception system in bionic micro air vehicles, akin to insect sensory neurons, handles internal and external stimulus information. However, current onboard mechanoreception methods add weight and necessitate additional power. Employing the embodied energy design paradigm, a lightweight intelligent membranous wing is proposed, mimicking the scarab beetle's hindwing morphology and kinematics. This wing serves multiple functions, including aerodynamic load‐bearing, flight piezo‐mechanoreception, and power supply. The beetle's semi‐tubular costa structure is replicated, featuring a compliant leading edge for upstroke aerodynamic load resistance. Inspired by beetle hindwing veins and membranes, the bionic wing with three membranous fields: anal, medial, and apical, using heat lamination of multilayer materials is fabricated. The bionic wing's aerodynamic performance closely mirrors that of a real beetle hindwing, enabling various flight maneuvers and validating its real‐flight potential. As a piezo‐mechanoreception receptor for micro air vehicles, the bionic intelligent wing senses flapping frequency, wing deformations, and collisions through voltage signals from piezoelectric materials in the three membranous fields. Energy harvested from flapping‐wing motion powers onboard light intensity and ultraviolet sensors for mobile 3D environmental monitoring. This integration of aerodynamics, mechanoreception, and power supply via embodied flapping energy offers a novel approach for designing future intelligent flapping‐wing micro air vehicles.

Towards More Efficient Electric Propulsion UAV Systems Using Boundary Layer Ingestion

The implementation of distributed propulsion and boundary layer ingestion for unmanned aerial vehicles represents various challenges for the design of embedded ducts in blended wing body configurations. This work explores the conceptual design and evaluation of DP configurations with BLI. The aerodynamic integration of each configuration is evaluated following a proposed framework, including simulation analysis. Power saving coefficient and propulsive efficiency were compared against a baseline podded case. The results show the optimal propulsion configuration for the BWB UAV obtaining 3.95% of power benefit and propulsive efficiency (ηp>80%). Indeed, the aerodynamic integration effects for the proposed design maintain the BWB’s aerodynamic efficiency, which will contribute to longer endurance and better performance.

Special issue on all‐electric and hybrid‐electric flight

Special issue on all‐electric and hybrid‐electric flight

On the implementation of flux limiters in algebraic frameworks

The use of flux limiters is widespread within the scientific computing community to capture shock discontinuities and are of paramount importance for the temporal integration of high-speed aerodynamics, multiphase flows and hyperbolic equations in general.Meanwhile, the breakthrough of new computing architectures and the hybridization of supercomputer systems pose a huge portability challenge, particularly for legacy codes, since the computing subroutines that form the algorithms, the so-called kernels, must be adapted to various complex parallel programming paradigms. From this perspective, the development of innovative implementations relying on a minimalist set of kernels simplifies the deployment of scientific computing software on state-of-the-art supercomputers, while it requires the reformulation of algorithms, such as the aforementioned flux limiters.Equipped with basic algebraic topology and graph theory underlying the classical mesh concept, a new flux limiter formulation is presented based on the adoption of algebraic data structures and kernels. As a result, traditional flux limiters are cast into a stream of only two types of computing kernels: sparse matrix-vector multiplication and generalized pointwise binary operators. The newly proposed formulation eases the deployment of such a numerical technique in massively parallel, potentially hybrid, computing systems and is demonstrated for a canonical advection problem.

ЕФЕКТИВНА ТЯГА ТА ЗОВНІШНІЙ ОПІР АВІАЦІЙНОЇ СИЛОВОЇ УСТАНОВКИ

Increasing the efficiency and effectiveness of a gas turbine engine can be achieved through a comprehensive review of all tasks that determine the parameters and characteristics of an aircraft power plant and aircraft. An important place in this complex is occupied by the problem of obtaining the most efficient traction and power plant based on the integration of the parameters and characteristics of the nacelle and gas turbine engine, consisting of a universal gas generator module and a turbofan module. Reducing the negative impact of the engine nacelle module on effective traction and effective specific fuel consumption is an urgent problem that can be solved based on the results of studies of the integration parameters and characteristics of the engine nacelle of the gas generator module and the gas turbine engine with the turbine-fan extension module, namely, with the implementation of structurally layout diagram of a gas turbine engine with a modular design with a rear arrangement of a turbofan attachment. For modern power plants with bypass gas turbine engines with a large bypass ratio, the external resistance is 2-3 % of the engine thrust during cruising operation. The results of experimental studies have shown that the external resistance of power plants with bypass gas turbine engines of modern supersonic aircraft is 4-6 % of the engine thrust during cruising operation. The paper considers the issues of aerodynamic integration of a gas turbine engine and a nacelle of an aircraft power plant. Aerothermogasdynamic integration of a gas turbine engine and an aircraft provides for the coordination of the parameters of the working process and the characteristics of the gas turbine engine and the parameters and characteristics of the nacelle of the aircraft in order to obtain optimal parameters and characteristics of the aircraft in the design flight conditions. The dependences of the relative effective thrust on the flight velocity are obtained. The obtained dependencies show the influence of the external resistance of the engine nacelle on the effective thrust of the bypass engine at subsonic flight velocities. The calculations were performed to lengthen the nacelle in the range from 4 to 8.

Theoretical fundamentals of airframe/propulsion integration for high-speed aircraft

Fundamental features of aerodynamic interference and integration of airframes and air-breathing jet engines for high-speed flight vehicles are studied within the framework of supersonic small perturbation theory. Both the influence of airframe components on air intakes performance and influence of intakes on vehicle external aerodynamics are under consideration. Analytical relations and specific examples show that significant favorable interference between airframes and air intakes can be realized by using preliminary compression of the flow in front of intakes at flight Mach numbers exceeding approximately 3.

Fluid flow analysis of composite material-based wind turbine blades using Ansys

The environment-friendly energies are wind, solar, wave and marine current power. In the recent period, the researchers moved to computer simulation from the experimental and numerical analysis. The purpose is to tackle design problems through the optimisation of the present technology and improvement in the efficiency of the wind turbines for long-term sustainability. Therefore, the present research analyses the performance of the wind turbine blade with aerodynamic and structural integrity challenges. Computational fluid dynamics (CFD) is a very powerful tool to solve a wide range of industrial and non-industrial fluid flow problems. CFD, as a promising technique in the wind engineering research, has attracted growing interest in the past two decades. Compared with the conventional experimental approaches, CFD could provide more details about flow field without any need for complicated control and measurement systems. It also provides an inexpensive solution to performing systematic analyses, such as the parametric studies required for performance optimisation of wind turbine blades. Ansys Fluent CFD computer simulation tool has high potentials to determine the effectiveness of air foils and efficiency of turbine blades. This tool provides a qualitative and quantitative prediction with confidence in impact of fluid flow over the wind turbine blade.

Methodology for the Assessment of Distributed Propulsion Configurations with Boundary Layer Ingestion Using the Discretized Miller Approach

The growing global environmental awareness has motivated the search for more fuel-efficient aircraft propulsion systems. In this context, a configuration based on distributed propulsion with Boundary Layer Ingestion (BLI) has been found to present potential performance benefits. The concept has been documented and explored extensively during the last few years and various aerodynamic integration issues, such as: high levels of distortion and low intake pressure recovery; have been identified as factors that may be detrimental in realizing the technology full potential. Parametric and parallel compressor (PC) approaches have been used to assess the effect of these aerodynamic issues on propulsors fan performance. However, in the context of BLI, these tools are unable to assess the effects of combined radial and circumferential distortion that are present. In order to assess the combined distortion patterns and the effects of distortion at component and system levels, this study uses a novel method based on semi-empirical correlations denominated the Discretized Miller (DM) approach. This method was developed for BLI systems previously by the author, and it is now incorporated into the propulsor performance method to assess the effects of the combined radial and circumferential distortion patterns. The performance analysis, undertaken at a component and system level, aims to assess several propulsion architectures, using Thrust Specific Fuel Consumption (TSFC) as figure of merit. To define the suitability of the distributed propulsor array in this study, an airframe layout based on the N3-X aircraft concept and High Temperature Superconducting (HTS) electric motor capabilities were assumed. The key contribution of this study is to enable the introduction of the concept of thrust split between energy source and propulsion system in the system analysis, and thereby, allows the assessment of its effects on different propulsion system layouts, while considering the BLI induced distortion. The results obtained with this alternative performance method showed that BLI reduces the fan efficiency of a conventional fan by approximately 2%, whilst corroborating the TSFC trends observed in previous studies. The study also indicates that when sizing effects of propulsors and core-engines were neglected, a propulsion system configuration with 75% thrust split was found optimum.

Discretized Miller approach to assess effects on boundary layer ingestion induced distortion

The performance of propulsion configurations with boundary layer ingestion (BLI) is affected to a large extent by the level of distortion in the inlet flow field. Through flow methods and parallel compressor have been used in the past to calculate the effects of this aerodynamic integration issue on the fan performance; however high-fidelity through flow methods are computationally expensive, which limits their use at preliminary design stage. On the other hand, parallel compressor has been developed to assess only circumferential distortion. This paper introduces a discretized semi-empirical performance method, which uses empirical correlations for blade and performance calculations. This tool discretizes the inlet region in radial and circumferential directions enabling the assessment of deterioration in fan performance caused by the combined effect of both distortion patterns. This paper initially studies the accuracy and suitability of the semi-empirical discretized method by comparing its predictions with CFD and experimental data for a baseline case working under distorted and undistorted conditions. Then a test case is examined, which corresponds to the propulsor fan of a distributed propulsion system with BLI. The results obtained from the validation study show a good agreement with the experimental and CFD results under design point conditions.

Signal Integrity Considerations Applied to Automotive Grounding System's Design

Designing electric circuits which have the vehicle's body as a part of the current's path is a common practice in the automotive industry. In this case, the signal integrity is affected by many variables, e.g. the body's shape and its constituent materials. Nevertheless, the design of the vehicle's body is generally based only on esthetic and aerodynamic factors and signal integrity is not taken into account. This is not a great concern anyway, since this kind of signal usually comes from power supply and the electrical and electronic devices might work (at least partially) even with a voltage level decrease. However, although power supply signals are theoretically continuous, higher frequency components can be noticed through measurements. Besides that, the implementation of Power Line Communication system in vehicles is being studied lately, which means that the traditional power lines would also carry information signals, with associated high frequency content. These observations lead to a concern about the body's behavior when conducting higher frequency currents, since it is not considered for the design of the vehicle's grounding systems. In this case, it is desirable that these spurious frequency components have a minimum impedance path to the battery's negative pole. This goal can be achieved by calculating optimal points for the grounding points. However, this is not an easy task, since there are no analytical equations for the impedance in this case. Hence, this paper proposes the use of the Genetic Algorithm as a tool for numerically calculating the best grounding points in a vehicle, through the electromagnetic simulation software ANSYS HFSS®.

Estudio de tecnologías innovadoras para sistemas de propulsión en aeronaves.

<p>Ecuador es un país con una economía emergente, elcual está comenzando a establecer una plataforma deinvestigación en diferentes áreas de la tecnología. Eneste marco, la industria aeroespacial se ve como uncampo prometedor de investigación, debido a las nu-merosas ventajas para los servicios de vigilancia, trans-porte, infraestructura, comunicaciones, entre otros.Para mantener a la industria de la aviación en uncamino de desarrollo sostenible y favorecer el creci-miento de esta en diversas áreas, es necesario crearnuevos sistemas de propulsión los cuales presentenbeneficios en términos de consumo de combustible, re-ducción de emisiones y ruidos. En este ámbito, nuevastecnologías como PTeD, BLI y HTS exhiben ventajaspotenciales para mejorar el desempeño de las aero-naves. En el siguiente trabajo se utiliza un enfoqueparamétrico para presentar una revisión de estas tec-nologías y se examinan los beneficios que puedenbrindar en términos de consumo energético. Tambiénse resaltan los desafíos que se necesitan vencer para<br />poder implantar esta tecnología en aeronaves.</p>

Opportunities and challenges for distributed propulsion and boundary layer ingestion

Purpose – The performance benefits of boundary layer ingestion (BLI) in the case of air vehicles powered by distributed propulsors have been documented and explored extensively by numerous studies. Therefore, it is well known that increased inlet flow distortion due to BLI can dramatically reduce these benefits. In this context, a methodology that enables the assessment of different propulsion architectures, whilst accounting for these aerodynamic integration issues, is studied in this paper. Design/methodology/approach – To calculate the effects of BLI-induced distortion, parametric and parallel compressor approaches have been implemented into the propulsion system analysis. The propulsion architectures study introduces the concept of thrust split between propulsors and main engines and also examines an alternative propulsor configuration. In the system analysis, optimum configurations are defined using thrust-specific fuel consumption as figure of merit. Findings – For determined operating conditions, t...

Aerodynamic configuration optimization by the integration of aerodynamics, aerothermodynamics and trajectory for hypersonic vehicles

The problem of aerodynamic configuration design optimization is a multidisciplinary design optimization (MDO) problem, and recently the MDO method is widely adopted in the field of hypersonic vehicle configuration design. From the aerodynamic point of view, the aerodynamics, aerothermodynamics and trajectory are considered in this paper. Generally speaking, the aerodynamic characteristics, aerodynamic heating and trajectory are determined by the aerodynamic configuration and the design of flight trajectory. The design method considering these three disciplines is proposed. The parametric geometrical configurations are proposed, and the aerodynamic characteristics are predicted by the rapid and effective engineering method. The optimization of aerodynamic configuration considering the integration of aerodynamics, aerothermodynamics and trajectory is investigated based on the parametric geometrical configuration. Maximum lift-to-drag ratio, maximum range of the trajectory and minimum total heat load of the stagnation point are chosen as the three optimal goals. The detailed research indicates that the optimal configurations and trajectories with different weighting factors can be obtained by the optimization, and there are obvious differences between them. The optimal configuration and flight trajectory obtained by the optimization can be used as the feasible schemes in the future work.

Structural and Conceptual Design Analysis of an Axial Compressor for a 100 MW Industrial Gas Turbine (IND100)

The structural design of the IND100 axial compressor requires a multistage interrelationship between the thermodynamic, aerodynamic, mechanical design and structural integrity analysis of the component. These design criteria, sometimes act in opposition, hence engineering balance is employed within the specified design performance limits. This paper presents the structural and conceptual design of a sixteen stage single shaft high pressure compressor of IND100 with an overall pressure ratio of 12 and mass flow of 310 kg/s at ISOSLS conditions. Furthermore, in order to evaluate the conceptual design analysis, basic parameters like compressor sizing, load and blade mass, disc stress analysis, bearings and material selections, conceptual disc design and rotor dynamics are considered using existing tools and analytical technique. These techniques employed the basic thermodynamic and aerodynamic theory of axial flow compressors to determine the temperature and pressure for all stages, geometrical parameters, velocity triangle, and weight and stress calculations of the compressor disc using Sagerser Empirical Weight Estimation. The result analysis shows a constant hub diameter annulus configuration with compressor overall axial length of 3.75 m, tip blade speed of 301 m/s, maximum blade centrifugal force stress of 170 MPa, with major emphasis on industrial application for the structural component design selections.

Aerodynamic Installation Effects of an Over-the-Wing Propeller on a High-Lift Configuration

Preliminary design studies indicate that a cruise-efficient short takeoff and landing aircraft has enhanced takeoff performance at competitive direct operating costs when using high-speed propellers in combination with internally blown flaps. The original tractor configuration is compared to an over-the-wing propeller, which allows for noise shielding. An additional geometry with partially embedded rotor similar to a channel wing is considered to increase the beneficial interaction. This paper shows the aerodynamic integration effects with a focus on climb performance and provides an assessment of the three aforementioned configurations for a simplified wing segment at takeoff conditions. Steady Reynolds-averaged Navier–Stokes simulations have been conducted using an actuator disk model and were evaluated based on the overall design. Interacting with the blown flap, the conventional tractor propeller induces large lift and drag increments due to the vectored sliptream. Although this effect is much smaller for an over-the-wing configuration, by halving the lift augmentation, the lift-to-drag ratio and the propulsive efficiency are considerably improved. Besides a moderate lift gain, the main advantage of a channel wing design is the location of the thrust vector close to the center of gravity resulting in a smaller nosedown pitching moment due to thrust. A disadvantage of over-the-wing propellers is the inhomogeneous inflow at higher velocity, which leads to oscillating blade loads and reduced efficiency.

Aeroelastic mysteries in avian flight

Avian flight is one of the remarkable achievements of vertebrate evolution. Thereby, the birds encountered, in principle, the same flight-technical problems and challenges as the human aircraft designers. From an aeronautical point of view, and with the knowledge and experience of modern aircraft design, the present study demonstrates that concealed aeroelastic effects and phenomena are also of basic importance in avian flight. Structural wing asymmetries play a fundamental role. First, as basis for the aeroelastic investigations, significant flight relevant anatomical and structural characteristics of the complex biotechnical architecture of avian wings are exposed. The further considerations are then focussed on two conspicuous asymmetric structural particularities of the wing, which contribute essentially to active flight ability of birds—an asymmetric positioning of the shaft in the vane of the primary flight feathers, and just so the eccentric location of the bony skeleton in the wing profile close to the leading edge. Ornithologists consider the asymmetry of the flight feathers as a diagnostic tool for aerial capability. However, this thesis still remains a topic of controversial debates. The study shows evidently that the magic structural wing asymmetries are imperative aeroelastic requirements for efficient flight, in particular to ensure structural strength and stability of the wing, as well as aerodynamic integrity. But these asymmetries are also fundamental to active aerodynamic generation of lift and thrust in wing flapping.

Control-Oriented Design Using Surrogate-Based Optimization and Existence Conditions for Robust Performance

M ISSION capability of a vehicle is ultimately evaluated by closed-loop performance. Such capability depends on a synergistic integration of aerodynamics, structures, propulsion, and control, which results in flight dynamics that are optimal for the mission. Unfortunately, most systems such as aircraft are traditionally designed using a sequential series of open-loop optimizations that cannot account for, or optimize, any synergistic integrations. A formulation for design that inherently considers control must therefore be developed to enable optimal closed-loop performance. The issue of cost function is actually quite critical to the inclusion of control synthesis for design optimization. Every discipline has metrics that are unique to their objectives, so a single cost that encompasses all these metrics can be challenging to formulate. One approach that considers vibration control uses norms, both for vibration level and effort, as a cost in a linear-quadratic framework [1]. A mixed-norm approach is formulated that considers both H2 andH1 in summation to represent independent metrics of the design [2]. A positive-real condition across frequency is also introduced as a cost that has time-domain interpretations for design [3]. Several formulations formulate cost functions and solution methodologies for designs that include linear matrix inequalities (LMIs) associated with H1-norm synthesis. One generates a nonconvex formulation and uses iterations to solve the associated optimization [4]. Another approximates functions associated with perturbed state-spacematrices as LMIs to be solved using an iterative approach [5]. A two-step procedure is used for an optimization coupled with an LMI solver for the controller [6] as an multidisciplinary optimization approach. Another approach considers an iterative sequential control design and a coupled redesign with each iteration involving the solution of an LMI [7]. This Note introduces a control-oriented approach for design that avoids the common difficulties of simultaneous structure-control design, which is known to be nonconvex [8–11]. The approach actually considers an existence question that notes if a controller exists for a given structure that achieves a desired level of performance. The approach does not design both the structure and control to optimize a closed-loop norm; rather, it designs a structure for which a controller exists that optimizes a closed-loop norm. Formulations using control synthesis to minimize an H1-norm metric and anH2-norm are derived using their appropriate existence conditions. As important, a solution methodology is used based on surrogate modeling to avoid the iterations and expensive computations associated with techniques doing design with LMI expressions. The surrogate-based optimization is shown to be efficient and effective and exploring a design space to optimize the closed-loop metric.

Optimizing the External Shape of Vehicles at the Concept Stage: Integration of Aerodynamics and Ergonomics

Optimizing the External Shape of Vehicles at the Concept Stage: Integration of Aerodynamics and Ergonomics

Comparison of Conventional and Compression Pylon Designsfor an Underwing Nacelle

This paper addresses one of the key components required to produce an environmentally friendly aircraft by reducing drag (and hence fuel consumption) through improved aerodynamic integration of the wing, pylon, and nacelle. The results of a computational investigation comparing the aerodynamic performance of a compression pylon design to a DLR F6 based conventional pylon design are presented in this paper. As with other computational predictions, the total lift and total drag were overpredicted. The change in drag between the wing body and the wing-body nacelle-pylon configurations was underpredicted by 14% at CL = 0.5. This validated CFD method was then used to investigate a compression pylon design. The results showed that a compression pylon produces an increase in lift and a reduction in drag. At zero degree angle of attack the total drag coefficient was reduced by at least 0.0006. The effect of the pylon is primarily inboard of the wing.