1,721,032 research outputs found
Efficient multi-stage aerodynamic topology optimization using an operator-based analytical differentiation
No full textA high-performance density-based topology optimization tool is presented for laminar flows with focus on 2D and 3D aerodynamic problems via OpenFOAM software. Density-based methods are generally robust in terms of initial design, making them suitable for designing purposes. However, these methods require relatively fine resolutions for external flow problems to accurately capture the solid-fluid interfaces on Cartesian meshes, which makes them computationally very expensive, particularly for 3D problems. To address such high computational costs, two techniques are developed here. Firstly, an operator-based analytical differentiation (OAD) is proposed, which efficiently computes the exact partial derivatives of the flow solver (simpleFOAM). OAD also facilitates a convenient development process by minimizing hand-coding and utilizing the chain-rule technique, in contrast to full hand-differentiation, which is very complex and prone to implementation errors. Secondly, a multi-stage design process is proposed to further reduce the computational costs. In this technique, instead of using a fixed refined mesh, the optimization processes are initiated with a coarse mesh, and the converged solutions are projected to a locally refined mesh (as an initial guess) for a secondary optimization stage, which can be repeated to obtain a sufficient accuracy. A set of 2D and 3D laminar aerodynamic problems were studied, which promisingly confirmed the utility of the present approach, which can be adopted as a starting point for developing a design tool for large-scale aerodynamic engineering applications. In addition, the 3D problems indicated that less than 3 % of total optimization CPU-time is devoted to OAD, and multi-staging up to 45 % has reduced the overall costs.</p
Designing high aspect ratio wings: a review of concepts and approaches
No full textIn response to escalating environmental concerns and stringent economic constraints, there is an urgent need to develop aircraft technologies and configurations that substantially enhance efficiency. A prominent trend in aircraft design aimed at minimizing lift-induced drag, improving fuel efficiency, and mitigating emissions is the adoption of increased wing Aspect Ratio (AR). This paper examines the evolution and current advancements in High Aspect Ratio Wing (HARW) and Ultra-High Aspect Ratio Wing (UHARW) configurations for next-generation transport aircraft. Beginning with a historical overview of wing AR in transport, the paper examines the progress in designing both conventional and novel HARW/UHARW configurations. It reviews a range of promising concepts, such as strut-braced wing, truss-braced wing, twin-fuselage, and folding wingtips, for their potential in HARW applications. The paper emphasizes tailored conceptual design methods and tools specifically developed for HARW/UHARW configurations. It provides an in-depth analysis of preliminary design approaches for HARW aircraft, systematically covering aspects including aerodynamic, aeroelastic, aerostructural, and experimental designs. Key insights from leading-edge research are distilled, highlighting the significant advancements and pinpointing the current challenges in the field. The comprehensive review underscores the critical role of HARW/UHARW in enhancing aircraft performance, particularly in fuel efficiency and environmental impact, setting the stage for future transformative developments in aircraft efficiency
Investigations on the potentials of novel technologies for aircraft fuel burn reduction through aerostructural optimisation
No full textA physics-based optimisation framework is developed to investigate the potential advantages of novel technologies on the energy efficiency of a midrange passenger aircraft. In particular, the coupled-adjoint aerostructural analysis and optimisation tool FEMWET is modified to study the effects of active flow control at different load cases for conventional and unconventional wing configurations. This multidisciplinary design optimisation (MDO) framework presents the opportunity to optimise the wing considering static aeroelastic effect and, by its gradient-based method, save substantial computational time compared to high-fidelity tools, keeping a satisfying level of accuracy. Two different configurations are analysed: a forward- and backward-swept wing aircraft, developed inside the Cluster of Excellence SE2A (Sustainable and Energy-Efficient Aviation). The forward-swept configuration is sensitive to the aeroelastic stability effect, and the backward configuration is influenced by the aileron constraint. They may lead to a weight increment. Sensitivity studies show the possible role of key parameters on the optimisation results. The highest fuel weight reduction achievable for the two configurations is 5.6% for the forward-swept wing and 9.8% for the backward configuration. Finally, both optimised wings show higher flexibility
Next steps in aerostructural design of ultra-high aspect ratio wings
No full textThis paper presents the authors’ research work on the aerostructural design of Ultra-High Aspect-ratio Wings (UHARW). Firstly, aircraft configurations suitable for UHARW, especially unconventional configurations, are introduced and discussed. Then the aircraft conceptual design and analysis framework developed for the unconventional UHARW aircraft is described. The UHARW of the conceptually designed Strut-Braced Wing (SBW) and twin-fuselage aircraft are further investigated by employing a series of nonlinear aerostructural optimization methods, including the influences of aileron design and flutter constraint on the ultra-high aspect-ratio SBW design
Comprehensive approach for aerostructural optimisation of ultra-high aspect ratio wings
No full textThis paper presents a comprehensive study on the aerostructural design of Strut-braced Wing (SBW) aircraft featuring Ultra-High Aspect Ratio Wings (UHARW). A medium-fidelity, coupled adjoint aerostructural optimisation method was introduced and applied to investigate various aspects of SBW aircraft optimisation. The research encompasses a series of studies that consider geometric nonlinearities, flow transition, aileron effectiveness and flutter constraints, specifically focusing on medium-range SBW aircraft. The paper presents the optimisation results and provides preliminary insights into the aerostructural characteristics of SBW aircraft featuring UHARW designs
Assessment of potential commercial success of business jets with natural laminar flow
No full textThe present research investigates the potential application of the natural laminar flow wing technology to business jet market segments from light to long-range jets. A database of existing business jets was generated to determine the range extension as a potential driver of customer interest. A conceptual design of several configurations for each market segment was performed to investigate potential improvements in the aircraft flight range, operating costs, and price changes using the technology. An initial sizing module and a low-fidelity multidisciplinary design optimization were used to size all aircraft. Results demonstrated a 13–30% increase in the flight range depending on the aircraft concept. Long-range jets with natural laminar flow could not achieve significant range extension due to a combination of the design airspeed and maintenance costs. A rapid increase in acquisition prices for all aircraft suggested that super-midsize and large jets that combine relatively low empty weight and high range extension could be more favorable options compared to other segments, but a significant reduction of acquisition costs and an increase in operating flight hours are required to make the technology implementation successful
An aircraft from nothing - towards configuration design of flying vehicles using topology optimization
No full textHow should the future transport aircraft look like? In other words, if we want to carry a certain amount of payload over a certain distance, with a given set of technologies, how should the flying vehicle look like to e.g. minimize energy consumption? The choice of aircraft configuration has so far been a human-driven task. Designers, based on their knowledge, experience, and of course bias used to suggest different configurations, each with its pros and cons. It is accepted that to reach the goal of minimum emission novel configurations might be needed compared to the traditional tube and wing configuration. There are multiple different disruptive configurations have been suggested so far by various industries and academics. Which one is the best, we do not know! Even if we can compare them all and find the best one, it does not mean that there is no better configuration. In this work, we introduce the idea of aircraft configuration design from scratch using multidisciplinary topology optimization. As the first step, a novel approach is presented for aerodynamic topology optimization in external flows. This approach is used to create an object out of nothing for the best aerodynamic performance. The outcome showed a surprise configuration, which outperforms the available flying objects in its regime, i.e., the flying regime of micro air vehicles
Aircraft-level sensitivities of electric network component performance for (hybrid-) electric aircraft
No full textResearch on electric aviation energy networks tends to focus on either detailed studies of individual subsystems, or full-aircraft analyses that use highly simplified network (component) models. This paper aims to bridge that gap by performing sensitivity studies for various network parameters (HVDC cables, power converters, and motors), evaluating their effect on both the system and aircraft level. This is achieved through a combination of higher-fidelity explicit modeling of the network components and conceptual aircraft design software. This analysis is applied to a parallel-electric regional jet and a fully-electric commuter aircraft. The effects of parameter variations within literature-supported ranges are evaluated on component, network and aircraft mass for a given mission profile. Results show that the most influential parameters are the level of DC voltage in power transmission, the cable material, and the achievable mission-average efficiency of the electric motor. Individual component mass variations of over 100% can be observed within the investigated ranges; with variations of up to 10% of the aircraft mass for the parallel-electric jet. Aircraft mass variations for the fully-electric aircraft are up to 5%, with the required battery size due to component efficiency changes as driving factor. Results show that for large aircraft, the network is highly sensitive to power requirements. For small aircraft the network is more sensitive to mission energy requirements
Towards optimal wing design for novel airframe and propulsion opportunities
No full textStrict sustainability objectives have been established for the upcoming generation of aircraft. A promising innovative airframe concept is the ultra-high-aspect-ratio Strut-Braced-Wing Aircraft (SBWA). Hydrogen-powered concepts are strong candidates for sustainable propulsion. The study investigates the influence of Liquid Hydrogen (LH2) propulsion on the optimal wing geometry of medium-range SBWA for minimum-cost and minimum-emission objectives. Multiobjective optimizations are performed in two optimization frameworks of differing fidelity for both kerosene- and LH2-propelled SBWA concepts. Furthermore, a range of Pareto-optimal designs show the changes in the optimized planform for variable weighting of the two objectives. The results show that the differences in the optimal wing geometry between the kerosene- and LH2-powered results for each respective objective function are small. For both aircraft, the minimum-emission objective optimizes for lower fuel burns and hence lower emissions, albeit at an increase in wing structural mass. The minimum-cost objective balances the reductions in structural and fuel masses, resulting in a lighter design at lower aspect ratios. Other wing-shape parameters only have minor contributions. Although the wing aspect ratios for both objectives differ by ca. 50%, the actual changes are only 2.5% in fuel and 1.5% in Direct Operating Cost (DOC). Due to a larger set of design variables used in the higher-fidelity optimizations, further parasite and wave drag reduction opportunities result in increased optimal aspect ratios
Dataset in support of the thesis 'Credibility-based optimisation of (Hybrid-) Electric Aircraft '
No full textData is available 'on request' please complete the form at https://library.soton.ac.uk/datarequest
This dataset contains results presented in the thesis 'Credibility-based optimisation of (Hybrid-) Electric Aircraft '. The dataset contains 3 folders:
1. Credibility: Python files used to create the credibility curves for laminar flow and structural weight reductions.
2. Networks: SUAVE simulation results for all variants used in the sensitivity studies for the boosted-turbofan aircraft and the fully-electric aircraft.
3. TMS: SUAVE simulation results for all variants used in the sensitivity studies for both TMS architectures (with and without skin heat exchanger).
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