Aerospace Systems最新文献

Aircraft icing can significantly degrade aerodynamic performance and compromise flight safety, highlighting the need for efficient prediction of icing characteristics and critical influencing factors. In this study, a structured set of icing simulation parameters was defined by identifying key variables and constraining their ranges in accordance with airworthiness requirements of intermittent maximum icing conditions. According to the simulation results, it concludes that heavier ice accretion leads to increased surface roughness and consequently more severe aerodynamic degradation under the intermittent maximum icing conditions. Within this admissible domain, representative samples were generated and applied to FENSAP-ICE to simulate ice accretion on the reference aircraft airfoil, thereby constructing a comprehensive icing dataset with the iced mass as the output response. Based on this dataset, a surrogate model employing the Random Forest algorithm was developed, enabling rapid and reliable prediction of icing outcomes. Furthermore, sensitivity analysis was conducted to identify the dominant parameters governing the icing process, offering valuable insights into the core factors that critically influence aircraft icing behavior.

This study conducts a numerical investigation of the Richtmyer–Meshkov instability (RMI) at microscale Helium/Argon interfaces using the Direct Simulation Monte Carlo (DSMC) method. The hydrodynamic behaviour and evolutionary mechanisms governing the single-mode RMI with high-amplitude are discussed, with the consideration of different Mach numbers (Ma) ranging from 1.5 to 6.0. Key findings reveal two distinct evolutionary pathways. In the high-Mach regime (Ma ≥ 3), complex shock configurations form through the establishment of Mach stem, accompanied by sustained positive vorticity deposition along the slipstream. This persistent process drives cavity initiation at spike apices. In the low-Mach regime (Ma ≤ 2), gradual degradation of Mach stem to regular reflection configurations occurs, wherein viscous dissipation extinguishes the vorticity accumulation and suppresses cavity formation. Quantitative comparison with DSMC data demonstrates that the Zhang and Guo (ZG) theoretical model has a prediction error of less than 20% for the overall amplitude growth of RMI across different Ma numbers, yet overestimates the bubble amplitude growth with a prediction error of approximately 50%, particularly in the late nonlinear stage. A dedicated discussion on gas species is also presented, revealing that the ZG theoretical model aligns well with the DSMC-calculated overall amplitude growth at high Ma numbers, with relative errors below 20%. Furthermore, the influence of Ma on the discrepancy between ZG model predictions and DSMC data diminishes as the Atwood number increases.

The study deals with aerodynamic analysis of a general aviation aircraft Piper PA-24, a monoplane with low-wing configuration using FlightStream, a panel-method based vorticity solver. The present-day preliminary design phase requires a full-scale design analysis mainly to understand the design and aerodynamic performance in a fully integrated aircraft with all the external components attached to the aircraft. Unlike the discretised Navier–stokes equation-based solver, FlightStream uses potential flow Laplace equation to solve for the flow physics reducing the dependency on complex three-dimensional meshes for preliminary design stage analysis. The aircraft is predominantly analysed to observe the aerodynamic performance for angle of attacks varying from (-4^circ ) to (+20^circ ), and validated with the available experimental data. The study also includes the grid independence check and thrust coefficient analysis to optimize the aerodynamic performance at cruising conditions. The findings will benefit aerospace engineers and researchers involved in aircraft design, aerodynamic optimization, and rapid preliminary analysis.

This paper proposes a machine learning framework for accurately predicting the aerodynamic lift-to-drag ratio (CL/CD) of multi-stepped airfoils under varied flow conditions. Experimental wind-tunnel data were collected for multiple step configurations, and a stacked ensemble model combining XGBoost, Support Vector Regression (SVR), and K-Nearest Neighbors (KNN) with a Random Forest meta-learner was developed for prediction. The proposed model achieved a test R² of 0.9951 and a tenfold cross-validation R² of 0.9872 ± 0.0043, demonstrating superior accuracy compared to individual regressors. This approach provides a fast, data-driven alternative to conventional CFD simulations, enabling reliable prediction of aerodynamic performance and efficient airfoil optimization.

With the rapid development of the low-altitude economy, electric Vertical Take-off and Landing (eVTOL) aircraft have emerged as a key focus of advanced air mobility. Open rotor and ducted fan configurations are the two primary types, but their distinct effects on aerodynamic performance and stability require thorough quantitative investigation. This study establishes a high-fidelity computational framework based on the Reynolds-Averaged Navier–Stokes (RANS) equations, incorporating eddy viscosity corrections and the Multiple Reference Frame (MRF) method to accurately resolve the interactional flow fields between the open rotor/ducted fan and the airframe. The results demonstrate that the open rotor configuration significantly enhances the cruise lift-to-drag ratio, thereby improving cruise efficiency. In contrast, the ducted fan configuration exhibits superior pitch and yaw static stability, especially under crosswind conditions. The ducted fan generates a nose-down pitching moment and contributes to improved directional stability. However, both configurations are found to compromise roll stability. Quantitatively, this study clarifies the complementary advantages of open rotor and ducted fan systems in terms of efficiency enhancement and stability performance, providing valuable insights for propulsion system selection and conceptual design of eVTOL aircraft.

This study investigates the aerodynamic performance of the NACA 6412 airfoil with serrated trailing edges at various angles of attack (AOA) and Reynolds numbers. Two-dimensional and three-dimensional simulations were performed using Large Eddy Simulation (LES) and Reynolds-Averaged Navier-Stokes (RANS) models, and the results were compared with wind tunnel experiments at a Reynolds number of 4.52 × 10⁵. The primary objective was to assess the influence of trailing-edge serrations on lift and drag. The findings indicate that trailing-edge serrations, while generally associated with a slight increase in drag, contribute to improved lift characteristics and thereby enhance the overall aerodynamic efficiency, as reflected in a higher lift-to-drag ratio across varying angles of attack.

Efficient air–fuel mixing is essential for achieving stable combustion, reducing emissions, and enhancing the overall performance of gas turbine combustors. This study provides a detailed computational investigation of swirling air jet mixing in confined geometries, with direct relevance to air–fuel mixing processes in gas turbine applications. The simulations employed the realizable k–ε turbulence model and were validated against existing experimental data, showing strong agreement. Computational investigations were performed using ANSYS Fluent in enclosures of fixed length but varying diameter, achieved by progressively introducing annular jets to form multi-annular configurations comprising 2 to 6 jets. While the central jet is conceptualized as a fuel jet and the surrounding annular jets as air, all jets are modelled as air to isolate the fundamental mixing behaviour. The introduction of additional annular jets increases the total mass flow rate, significantly influencing internal flow structures. Clear signs of improved mixing were seen in the significant increase in the central recirculation zone (CRZ) and the corresponding decrease in centreline axial velocity. To gain deeper insight into the flow behavior, each set of jet’s configurations was investigated using two different swirl intensity combinations. Findings indicated that a greater difference in swirl strength enhanced the formation of the central recirculation zone (CRZ) and reduced axial velocities along the centerline, suggesting more effective interaction and mixing between the jets.

The paper presents an overview of manipulators and robots that can be used as part of a service spacecraft to implement methods for the active removal of space debris from near-Earth orbits as well as for structure assembly, and spacecraft maintenance. Some of the robots and manipulators described in the paper were originally intended for assembling various structures in weightlessness, for refueling spacecraft (SC) or for conducting inspections as a free-flying spacecraft. The feasibility of their use for active space debris removal should be further investigated, especially with regard to large and heavy structures. Many of the described manipulators and robots are already actively used in space and have proven themselves well.

The evolution of unmanned aerial vehicle (UAV) systems continues to accelerate due to the integration of advanced simulation environments that enable rapid design iteration and aerodynamic optimization. This study presents a parametric investigation into the influence of empennage configuration—specifically cant tail angle and vertical tailplane height—on the aerodynamic performance of fixed-wing UAVs. A total of thirty-six full-scale three-dimensional UAV models were developed using SOLIDWORKS, each utilizing the SD8020 airfoil for both the main and tail wings. The models incorporate combinations of three cant angles (30°, 45°, 60°), three tail heights (1.0 m, 1.5 m, 2.0 m), and four angles of attack (2°, 3°, 4°, 5°). High-fidelity aerodynamic analysis was conducted using steady-state Reynolds-averaged Navier–Stokes (RANS) simulations with the SST k–ω turbulence model in ANSYS Fluent. The results reveal that the configuration with a cant angle of 60°, tail height of 1.0 m, and angle of attack of 4° yielded the highest aerodynamic efficiency, exhibiting a 39% improvement in lift-to-drag ratio compared to the lowest-performing configuration. The findings provide actionable insight for UAV tail architecture design, supporting more efficient performance-driven development of autonomous aerial platforms.

By adopting the CFD based approach, the hypersonic flow nature is investigated under a Free-stream Mach number of 6 for two distinct re-entry configurations; namely, a spiked conical-nosed body, and a spiked T-shaped blunt-nosed body, each coupled with counterflow jets. A high-fidelity structured mesh and the SST k-omega Turbulence model within the Ansys Fluent framework are employed to capture flow phenomena like bow shock detachment, recirculation, and wake formation with finer precision. The analysis is performed on vital performance parameters such as aerodynamic drag, surface pressure and temperature distributions, and the effect of counterflow jets on shock stand-off distance and thermal load reduction. We find results indicating drag reduction of 52% by the conical blunt-nosed configuration compared to the T-Shape nose configuration and an increase in shock stand-off distance by 0.0175. Moreover, counterflow jets reduce the surface temperature by a maximum of 300 K at critical forebody regions, while the total pressure recovery improves by 50%. These findings affirm that nose shape is a critical parameter influencing the hypersonic flow control and thus offers new perspectives for the design optimization, with T-shaped configuration providing improved thermal protection and aerodynamic efficiency.