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Item Open Access What drives passengers towards sustainable aviation? A segmentation study of travel behaviour and environmental concern in Spain(Elsevier, 2025-09-01) Patino-Artaza, Helena; Suau-Sanchez, PereAir travel significantly contributes to greenhouse gas emissions, posing challenges for climate action. This study examines the attitudes and behaviours of Spanish air passengers, focusing on the relationship between environmental concerns and travel choices. Based on a survey of 1,206 participants, we employed exploratory factor analysis to identify three attitudinal clusters: “Status quo flyers,” “Environmentally conscious low-flyers,” and “Pragmatic moderates”. These segments display significant differences in travel frequency, environmental concern, perception of aviation’s impact, and willingness to adopt sustainable alternatives. While environmentally conscious travellers express willingness to reduce air travel, frequent flyers often resist behavioural changes, highlighting a persistent attitude-behaviour gap. The results emphasise the importance of targeted strategies to address the attitude-behaviour gap and promote sustainability in aviation. This research provides actionable insights for policymakers and industry stakeholders to foster sustainable travel behaviours in one of Europe’s largest aviation markets.Item Open Access Comparison of PCA and fractal analysis approaches in the evaluation of air-HSR intermodal network(Elsevier, 2025-10) Lu, Mengyuan; Perez, Edgar Jimenez; Mason, Keith; Li, LinlinThe importance of air transport and high-speed rail (HSR) in building comprehensive transportation systems has grown substantially in recent years. Evaluating the air-HSR intermodal network is essential in identifying the developmental hurdles and charting a course for its progress. This paper compares alternative methods for evaluating the performance of air-high-speed rail (HSR) intermodal networks, with a focus on developing a comprehensive index framework that considers multiple perspectives. Ten Chinese cities with viable air-HSR connectivity are assessed using principal component analysis (PCA) and Fractal Analysis. The study finds that while PCA provides a valuable high-level overview of air-HSR intermodal network integration by identifying major trends and key components, Fractal Analysis offers a complementary and more detailed evaluation by capturing local characteristics and complex spatial interactions. The combined use of PCA and Fractal Analysis ensures a comprehensive assessment, highlighting that Fractal Analysis is particularly effective for evaluating complex intermodal networks when spatial coherence and local variations are critical. The analysis provides decision-makers with a more balanced understanding of the intricate interrelationships between various aspects of the air-HSR intermodal network, which can inform policy decisions related to transportation infrastructure investment and development.Item Open Access Integrating causal analysis based on system theory with network modelling to enhance accident analysis(Taylor & Francis, 2025-12-31) Kaya, Gulsum Kubra; Humphreys, Mark; Camelia, Fanny; Chatzimichailidou, MikelaThis study integrates Causal Analysis based on System Theory (CAST) with network modelling to enhance accident analysis in aviation ground handling. Using 117 Passenger Boarding Steps (PBS)-related incident reports, the CAST analysis identified 74 flaws across 40 control actions, leading to four loss types. Approaching, inspecting, adjusting, and repositioning PBS were the most critical control actions contributing to incidents. Key contributory factors included issues around training, workload management, situational awareness, performance management, recruitment, organisational culture, procedures, equipment maintenance, and financial constraints. The integration of network modelling into CAST enhanced accident analysis by visualising complex interactions, offering deeper insights into accident causation and identifying critical nodes. This study demonstrates that combining CAST with network modelling enhances the understanding of accidents and safety risks, supporting evidence-based decision-making for aviation safety professionals and improving ground handling risk management strategies. Practitioner Summary: This study integrates CAST with network modelling to enhance accident analysis in aviation ground handling. Analysing 117 passenger boarding steps incidents, the study identifies critical control actions and contributory factors. Network modelling enhances CAST by revealing complex interactions, providing deeper insights into incidents, and supporting improved risk management strategies.Item Open Access Emergency = Emergency? usability evaluation of a novel emergency alerting system for cabin emergencies(Elsevier, 2025) Manikath, Elizabeth; Li, Wen-Chin; Piotrowski, PawelEmergencies in aviation often create huge media attention because the number of people involved are high and flying was once considered to be risky, which is still in the mind of some passengers. This study evaluated how passengers and cabin crew classified cases of emergencies. Further, detailed design requirements on the emergency alerting interface were explored. Therefore, two different prototypes of an emergency alerting interface were presented to participants (n = 160) with the task to evaluate the perceived usability (SUS) and the subjective workload using NASA TLX. The SUS scores for both prototypes were above average indicating a good usability. Red was the preferred colour and a triangle shaped icon with SOS. Broad menu designs with more icons than text were the preference of the users. Passengers as well as cabin crew identified medical emergencies and unruly passengers as emergencies. However, passengers also mentioned technical failure as a possible case whereas cabin crew was more concerned about fire and smoke. This study has substantiated the need for an emergency alerting system since it is expected that the number of medical emergencies and unruly passengers will most likely increase in the future.Item Open Access From Turing Test to Chinese Room Argument: how to apply artificial intelligence in aviation(Elsevier, 2025) Saunders, Declan; Li, Wen-Chin; Wang, ThomasThe emergence of artificial intelligence (AI) with advanced large language model (LLM) offers promising approaches for enhancing the capacity of textual analysis. Both the Turing Test and Chinese Room Argument explore AI’s understanding of human language, although both methodologies have dissimilar interpretation on AI’s ‘intelligence’. Current AI systems have demonstrated the capacity for achieving defined test goals for ‘intelligence’. The aviation industry is increasingly interested in adopting AI to improve efficiency, safety, and cost efficiency; with the Generative Pre-trained Transformers’ (GPT) capability to reduce resource-intensive analytics in accident causation classification. This study investigates the potential and challenges of using AI to analyze human factors involved in aviation accidents based on the Human Factors Analysis and Classification System (HFACS). Six subject-matter experts in aviation human factors and AI domain participated in this research. All participants were familiar with the HFACS framework to analyze aviation accident reports and the output of GPT which were based on the prompt engineering developed by the research team. This research creates a framework to perform its initial generation and training using GE 235 accident investigation report from Taiwan Transportation Safety Board (TTSB). Initial discoveries demonstrated that the AI model could populate the sub-dimensions of Level 1 HFACS framework with moderate accuracy, although there remains a high presence of hallucinations in generated outputs, with a lack of reproducibility in consecutive outputs with consistent input data. There are still different opinions on AI applications in real-world operations with ethics and safety concerns. While there is clear potential for GPT models to supplement accident analysis within the HFACS framework, there is still more work to integrate HFACS framework into GPT modelling for effective generation to accident data.Item Open Access Modeling multirotor wake interference in quadrotor eVTOL flight dynamics and handling qualities(Elsevier, 2025-10-01) Wang, Yeping; Ji, Honglei; Lu, Linghai; Zhou, PanThis study presents a good-fidelity flight dynamics model for a quadrotor eVTOL aircraft, with a particular focus on the effects of multirotor aerodynamic interference on vehicle stability and handling qualities. A dynamic vortex tube model, enhanced to account for aircraft angular motions, is developed and integrated with dynamic inflow theory to compute rotor-induced and interference velocities efficiently. The model is validated against wind tunnel data and benchmark trim results, demonstrating strong predictive accuracy. Incorporating this interference model into a 6-DoF flight dynamics framework reveals that multirotor wake interference significantly modify both static and dynamic stability characteristics, especially in low-to-medium speed regimes. Moreover, aerodynamic interference degrades incidence stability, reduces pitch and heave damping, and adversely affects phugoid behavior. In the lateral-directional axes, it destabilizes the spiral mode and introduces non-monotonic variations in Dutch roll stability. Handling qualities analysis using ADS-33E-PRF metrics shows that interference reduces pitch bandwidth from Level 1 to Level 2 and marginally deteriorates pitch and roll dynamic stability, while improving pitch-axis quickness. These findings demonstrate that multirotor aerodynamic interference is not merely a performance issue but a critical factor influencing flight control design and certification. The proposed modeling approach offers a computationally efficient yet physically grounded method for assessing multirotor eVTOL handling qualities across the full flight envelope.Item Open Access Design challenges and preliminary test results of a high temperature supercritical carbon dioxide dry gas seal test rig(University of Duisburg, Essen, 2025-04-09) Abdeldayem, Abdelrahman; Kissoon, Sajal; Anselmi Palma, EduardoSupercritical carbon dioxide (sCO2) has shown a high potential in power generation cycles to increase thermal efficiency and decrease the physical footprint. Supercritical CO2 power cycles operate at relatively high temperatures compared to steam and air, necessitating the development of new sealing materials. In this paper, the design challenges, development and preliminary test results of a 500oC, 200 bar sCO2 dry gas seals test rig are presented. The main rig components are pressure control devices (liquid pump and expansion valves), heat exchangers (liquid condenser, gas heaters, and air cooler), and measuring instruments. Various design challenges are identified due to the thermo-physical properties as well as the operating conditions of the sCO2 test rig such as the ice formation during start-up, heat loss to the ambient air, and material compatibility with the various test rig components. A thermodynamic design model has been developed to size the test rig components and estimate the gas conditions across the rig. The model includes tube and valve sizing, heat exchanger design, and thermal insulation models. The initial phase of the test campaign was conducted at Cranfield University (CU) to verify the ability of the test rig to deliver sCO2 at the required conditions and to validate the developed numerical models. The results showed the validity of the proposed setup to supply sCO2 steadily at 500oC and 200 bar at a flow rate of 15 kg/h. The heat exchanger model applied to a finned tube bundle air cooler showed close estimations to the test results with a maximum deviation in the heat capacity of 2.3%. The thermal insulation model including the heating tape showed reasonable predictions for the temperature rise across the heating sections with a maximum deviation from the experimental measurements of 10oC when the temperature rise was around 240oC. The suitability of using rock wool insulation and stainless steel 316 tubes with dry CO2 at 500oC was verified.Item Open Access Safety voice concept clean-up: examining the voice that challenges us to be safer(Elsevier, 2025-11-01) Paul, Jeanne; Pilbeam, Colin; Smallwood, AnnaSafety voice, the act of speaking up about safety concerns, is essential for preventing accidents and fostering an engaged safety culture. This study systematically reviewed 86 empirical studies of safety voice by operationalising and applying Podsakoff et al.’s (2016) four-stage framework for developing good conceptual definitions to assess its conceptual clarity, triggers, contextual variations, and measurement. This identified opportunities to refine definitions, theory, and hazard categorisation to enable proactive risk management. Current research on communication scope, directionality, and dyadic sender-receiver dynamics is fragmented which limits potential insights. Contextual disparities and Western culture biases affect generalisability. While senior leadership is key to a positive safety culture this focus is lacking. Addressing these areas through improved conceptual frameworks, hazard-voice models, and cross-industry comparisons will enhance proactive safety management, engagement, and resilience in high-risk industries.Item Open Access On residual tensile strength after lightning strikes(Elsevier, 2025-07-01) Xu, Xiaodong; Millen, Scott L. J.; Mitchard, Daniel; Wisnom, Michael R.The study of post lightning strike residual strength is still relatively underdeveloped in the literature. Different approaches including in-plane compression or flexural testing have been used, but in-plane tensile loading post-strike has not been studied in detail. Although previous attempts have been made to determine the residual strength using Compression-After-Lightning (CAL) tests on composite laminates, these have been limited and not readily applicable under tensile loads. Therefore, this work completes Tension-After-Lightning (TAL) testing at 75 kA on composite laminates, a more realistic peak current than previously reported for TAL tests, to assess the knock-down in strength post-strike. The measured average TAL failure stress was 716 MPa, a reduction of 23 % from the baseline tensile failure stress of 929 MPa in the literature. This confirms a similar knock-down factor reported at lower peak currents (e.g. 50 kA), but the new TAL specimen geometry ensures that the lightning damage is contained within both the lightning and TAL specimen widths. In addition, a new Finite Element (FE) based virtual test was conducted, considering 0° ply splitting, and validated with the TAL tests herein. The TAL simulation predicted the residual tensile failure stress well, within 6 % of the measured value.Item Open Access Through-the-thickness z-pinning reinforcements to improve energy absorption capabilities of CFRP crash structures: numerical development(Springer, 2025-01-01) De Biasio, Antony; Ghasemnejad, HessamThis study employs numerical methods to model through-the-thickness reinforcements in CFRP tubular structures under axial impact, investigating the influence of reinforcement configurations on crashworthiness performance. Experimental validation involves testing unpinned tubular structures to establish a baseline model. LS-DYNA finite element models simulate low-velocity axial impacts, incorporating energy-based tiebreak contacts or solid cohesive elements to describe interlaminar bridging. Through-the-thickness are introduced through a homogenous mesh system or locally refined mesh at pin locations. Various reinforced tube designs with different pin diameters and areal densities are examined to identify the optimal pinned design for crashworthiness. The research demonstrates numerically that pinning enhances crashworthiness performances in axial crushing of composite tubes.Item Open Access The effects of environmental conditions on the failure of double lap composite joints with different overlap lengths and adherend thicknesses(Elsevier, 2025-09-01) Paul, Aakash; Xu, Xiaodong; Shimizu, Takayuki; Wisnom, Michael R.This paper provides a comprehensive study of the effects of environmental conditions on the failure of Double Lap Joints (DLJ) with composite adherends of different overlap lengths and thicknesses. The environmental conditions tested are Room Temperature Dry (RTD), Hot Temperature Dry (HTD) and Hot Temperature Wet (HTW). The mechanical properties of both the adhesive and composite adherends were characterised at these environmental conditions, showing conflicting trends. A new way of presenting the data based on simple calculations of strength or fracture dominated failure allows all the data to be shown on a single plot, and satisfactorily explains the failure modes, failure loads and opposite trends observed for a total of 13 DLJ configurations tested at the three environmental conditions.Item Open Access Multidisciplinary design optimization of the NASA metallic and composite common research model wingbox: addressing static strength, stiffness, aeroelastic, and manufacturing constraints(MDPI, 2025-06-01) Dababneh, Odeh; Kipouros, Timoleon; Whidborne, James F.This study explores the multidisciplinary design optimization (MDO) of the NASA Common Research Model (CRM) wingbox, utilizing both metallic and composite materials while addressing various constraints, including static strength, stiffness, aeroelasticity, and manufacturing considerations. The primary load-bearing wing structure is designed with high structural fidelity, resulting in a higher number of structural elements representing the wingbox model. This increased complexity expands the design space due to a greater number of design variables, thereby enhancing the potential for identifying optimal design alternatives and improving mass estimation accuracy. Finite element analysis (FEA) combined with gradient-based design optimization techniques was employed to assess the mass of the metallic and composite wingbox configurations. The results demonstrate that the incorporation of composite materials into the CRM wingbox design achieves a structural mass reduction of approximately 17.4% compared to the metallic wingbox when flutter constraints are considered and a 23.4% reduction when flutter constraints are excluded. When considering flutter constraints, the composite wingbox exhibits a 5.6% reduction in structural mass and a 5.3% decrease in critical flutter speed. Despite the reduction in flutter speed, the design remains free from flutter instabilities within the operational flight envelope. Flutter analysis, conducted using the p-k method, confirmed that both the optimized metallic and composite wingboxes are free from flutter instabilities, with flutter speeds exceeding the critical threshold of 256 m/s. Additionally, free vibration and aeroelastic stability analyses reveal that the composite wingbox demonstrates higher natural frequencies compared to the metallic version, indicating that composite materials enhance dynamic response and reduce susceptibility to aeroelastic phenomena. Fuel mass was also found to significantly influence both natural frequencies and flutter characteristics, with the presence of fuel leading to a reduction in structural frequencies associated with wing bending.Item Open Access Complex network analysis of China's integrated air-high-speed rail network: topological characteristics, centrality measures, and cluster analysis(Elsevier, 2025-07-01) Lu, Mengyuan; Perez, Edgar Jimenez; Mason, KeithThis paper presents a comprehensive complex network analysis of China's integrated air-High-Speed Rail (HSR) network by constructing a directed weighted network and comparing its complex characteristics with its sub-networks. The findings reveal that, beyond small-world properties, the networks exhibit broad-scale characteristics with a rapid decline in degree distribution, deviating from the traditional scale-free model due to operational constraints and market saturation. Centrality analysis highlights the rising importance of secondary hubs, such as Xi'an, Kunming, and Zhengzhou, as strategic transit points linking urban centres and peripheral regions. The integrated network achieves enhanced efficiency through hybrid modularity, combining the aviation network's centralised structure with the HSR network's corridor-focused design. While this integration fosters economic connectivity and regional development, resilience challenges emerge due to reliance on high-centrality nodes. These findings offer implications for intermodal transport planning and regional development.Item Open Access Normalised diagnostic contribution index (NDCI) integration to multi objective sensor optimisation framework (MOSOF)—An environmental control system case(MDPI, 2025-05-01) Suslu, Burak; Ali, Fakhre; Jennions, Ian K.In modern aerospace systems, effective sensor optimisation is essential for ensuring reliable diagnostics, efficient resource allocation, and proactive maintenance. This paper presents Normalised Diagnostic Contribution Index (NDCI) integration into the Multi-Objective Sensor Optimisation Framework (MOSOF) to address application-specific performance nuances. Building on previous work, the proposed approach leverages a multi-objective genetic algorithm to optimise key criteria, including performance, cost, reliability management, and compatibility. NDCI is derived from simulation data obtained via the Boeing 737-800 Environmental Control System (ECS) using the SESAC platform, where degradation level readings across four fault modes are analysed. The framework evaluates sensor performance from the perspectives of Original Equipment Manufacturers (OEM), Airlines, and Maintenance Repair Overhaul (MRO) organisations. Validation against the Minimum Redundancy Maximum Relevance (mRMR) method highlights the distinct advantage of NDCI by identifying an optimal set of three sensors compared to mRMR’s six-sensor solution, and MOSOF’s multi-objective insertion enhances sensor deployment for different stakeholders. This integration not only expands the feasible solution space for sensor-pair configurations but also emphasises diagnostic value over redundancy. Overall, the enhanced NDCI-MOSOF offers a scalable, multi-stakeholder approach for next-generation sensor optimisation and predictive maintenance in complex aerospace systems. The results demonstrate significant improvements in diagnostics efficiency for stakeholders.Item Open Access Assessment of a liquid hydrogen conditioning system for retrofitting on kerosene designed turbofans(ASME , 2025-10-01) Rompokos, Pavlos; Kyritsis, Vasileios; Mourouzidis, Christos; Roumeliotis, IoannisAs energy transition to alternative fuels for civil aviation is likely to be gradual, hydrogen’s first entry to service may be implemented on existing gas turbine engines. In this paper a novel liquid hydrogen conditioning system for retrofitting on kerosene designed geared turbofans is assessed in terms of performance and engine rematching. The aim of the analysis is to identify emerging requirements for the design of the fuel and thermal management system within the constraints of a certified engine design. The conditioning system proposed, an LH2 preheater, enables the control of the gaseous hydrogen temperature at combustor entry and consists of a secondary combustor and a heat exchanger. The examined configuration considers various bleed source locations within the engine to supply the preheater system. For performing the analysis, a kerosene fueled engine has been designed and suitable integrated models capable to simulate the retrofitted hydrogen fueled engine as well as the LH2 preheater operation have been developed. The system performance has been analyzed for the different bleed source locations identifying operating limits and performance changes. From all the examined bleed source positions, utilizing the by-pass duct minimizes the impact on component rematching and engine efficiency. Additionally, through a gas path geometry multiparametric analysis, it was found that by readjusting the capacity of the high-pressure turbine and the core nozzle area the certified limits can be met for the retrofitted engine.Item Open Access Impact of high-aspect-ratio wing aircraft concepts on conventional tricycle landing gear integration(SAE International, 2025-05-10) Martin, Raphaël; Stockford, Jack; Smith, HowardTo comply with the Paris Agreement targets set in 2015, significant reductions in aircraft emissions are required. This demands a fundamental shift in aircraft design. Therefore, it is essential to study how future aircraft designs will affect the integration and design of landing systems. This research project examines the landing gear issues that arise from adopting specific future aircraft configurations. The study focuses on two primary configurations: the high-aspect-ratio wing and the ultra-high-aspect-ratio wing, with selected aircraft concepts from Cranfield University as baselines. It investigates the design and integration of conventional landing systems into these new aircraft concepts, highlighting the limitations posed by the modified airframes. The selected concepts include either telescopic or trailing arm arrangements, with attachment points on the wings or fuselage. A methodology for preliminary sizing of landing systems is presented, emphasizing automation and determining key performance indicators to assess the suitability of each solution for different aircraft architectures. The challenges of these novel airframes highlight opportunities to move away from conventional solutions and explore unconventional methods of interfacing between the aircraft and the ground.Item Open Access Total pressure distortion reconstruction methods from velocimetry data within an aero-engine intake at crosswind(European Turbomachinery Society, 2025-03-24) Piovesan, Tommaso; Zachos, Pavlos K.; MacManus, David G.The integration of Very High Bypass Ratio (VHBR) turbofan engines with short intakes may present challenges due to increased total pressure distortion, particularly under crosswind conditions. Current industrial practices rely on a limited number of intrusive pressure sensors arranged on rakes at the Aerodynamic Interface Plane (AIP), to characterise this total pressure distortion. However, non-intrusive measurement techniques provide a more effective way to capture the complex, unsteady flow fields within the intake, offering higher spatial resolution compared to conventional methods. In this study, velocity data obtained from Stereoscopic Particle Image Velocimetry (S-PIV) during wind tunnel tests of a short intake configuration were employed to reconstruct the instantaneous total pressure fields at the AIP within the intake. Two reconstruction methods were used: Direct Spatial Integration (DSI) of the momentum equation and the Poisson Pressure Equation (PPE). These methods were first applied to numerical data from RANS simulations. The results of the reconstruction of the total pressure field based on the S-PIV data were compared against rake measurements. The methods enabled a more comprehensive assessment of total pressure distortion, offering improvements over conventional sensor-based ap-proaches in identifying and characterising total pressure non-uniformities within an intake.Item Open Access Digital Twin-Based Health Management for Complex Aircraft Systems: Case Studies and Applications(IEEE, 2025-03-24) Wang, Chengwei; Fan, Ip-Shing; Plastropoulos, AngelosDigital Twin technology, initially conceptualized during the NASA's Apollo program, has evolved into a transformative tool for system health management, particularly in aviation. By integrating high-fidelity simulations, real-time sensor data, and predictive analytics, DTs enable significant innovation in Prognostics and Health Management methods. This paper explores the application of DTs in health management for complex aircraft systems, focusing on two critical subsystems: Flight Control Electrical Actuators and Main Landing Gear. Leveraging MATLAB Simscape, modular DT frameworks were developed to simulate these systems under nominal, degraded, and fault conditions. The inclusion of fault injection models enables the generation of realistic datasets to support predictive maintenance, alleviating difficulties in data availability. Two case studies are presented to illustrate the potential of DT-based approaches to reduce downtime, optimizing performance, and enhancing system reliability. This paper provides a comparative analysis of existing DT tools, highlighting their capabilities and limitations in aerospace contexts. While platforms such as MATLAB Simulink and ANSYS Twin Builder offer robust modeling capabilities, operational tools like AVIATAR and IBM Maximo excel in fleet management and predictive analytics. This comparison highlights the need for tailored DT solutions that balance real-time capabilities, scalability, and configurability. This study contributes to the growing body of knowledge on DT technology, offering insights into its role in enhancing aviation safety, efficiency, and sustainability. It serves as a guide for applying DT-based health management, paving the way for broader adoption in next-generation aerospace systems.Item Open Access Fundamental concepts of boundary-layer ingestion propulsion(American Institute of Aeronautics and Astronautics (AIAA), 2025-05-13) Lamprakis, Ioannis; Sanders, Drewan S.; Laskaridis, PanagiotisThis work further develops energy-based far-field methods by introducing Galilean covariance in work–energy relationships of flight. The novelty lies in how decomposition formulations are rederived from integral forms of the governing laws applicable to moving control volumes. It is shown that aerodynamic performance is best evaluated in a reference where the aircraft moves through the atmosphere. The advantages are clearly demonstrated through the formulation of a hypothesis on boundary-layer ingestion (BLI) power savings using a series of simplified flat plate–BLI propulsor configurations. This hypothesis links BLI power savings to the energy content within the boundary layer and the propulsor’s ability to attenuate the ingested boundary layer’s velocity profile. Extensive numerical studies on both laminar and turbulent flows are carried out to test this hypothesis, examining different levels of wake recovery achieved through a body force model propulsor with varying load distributions. Near-perfect wake attenuation is shown to yield maximum power savings, but only for higher-Reynolds-number flows, where the influence of aeropropulsive interference on upstream dissipation is minimal. The flat plate findings are extended to a 2D axisymmetric fuselage representation, where baroclinic losses become significant. A maximum power saving of around 8% is achievable at typical cruise conditions for a single-aisle passenger aircraft.Item Open Access Wind tunnel installation effects on a high-speed exhaust flow under large blockage(American Institute of Aeronautics and Astronautics (AIAA), 2025-05-19) Tsentis, Spyros; Goulos, Ioannis; Debiasi, Marco; Prince, Simon; Pachidis, Vassilios; Zmijanovic, Vladeta; Saavedra, JosèThis study presents a numerical investigation of wind tunnel installation effects on the exhaust flow for a high-speed system under a blockage ratio of 16.5%. The configuration features a nozzle and a cavity embedded at the base of an ogive-cylindrical body and is representative of future, high-speed exhausts. The work is motivated by the need of testing large, powered-on models and the size of most closed transonic tunnels available in academic research facilities. This combination leads to high blockage ratios and therefore severe flow distortion. The objective is to examine the installation effects and quantify the base flow similarity relative to unbounded conditions. The numerical approach is validated against experimental data. A jet vectoring effect is identified due to the pylon, which is intensified under choked tunnel operation. Additionally, a methodology is proposed, which allows base pressure to be compared to unbounded flow conditions. Results show that the pressure distribution agrees within 1.5% and 0.1% for the base and cavity walls, respectively. This demonstrates that local aerodynamic similarity can be established between large-blockage, tunnel-tested conditions and unbounded flow through the proposed approach. This enables the use of small-scale facilities for base flow studies of high-speed exhausts under large blockage.
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