Current Issue : July-September Volume : 2025 Issue Number : 3 Articles : 5 Articles
The main goal of the present study is to explore the noise mitigation potential using an active control strategy based on rotor phase synchronization. This work is focused on the effects of the inflow velocity on the noise interference effect. The inflow velocity does not affect the phase at which the interference phenomenon is observed, as expected. On the other hand, the intensity of the pressure fluctuations is influenced by the inflow velocity for all of the rotor phase shift conditions investigated. Specifically, as the inflow velocity increases, maintaining a constant rotational speed, in the Overall Sound Pressure Level graphs, a reduction of approximately 10 dB is observed. This effect also applies to cases of destructive interference, highlighting the remarkable versatility of this noise reduction technique....
This paper presents an attitude stabilization algorithm for a Low Earth Orbit (LEO) Earth-pointing spacecraft using magnetorquers as the only torque actuators and employing Model-Free Adaptive Control (MFAC) as the control algorithm. MFAC is a data-driven control algorithm that relies solely on input–output data from the plant. This paper validates the effectiveness of the proposed approach through numerical simulations in a specific case study. The simulations show that the proposed algorithm drives the spacecraft’s attitude to three-axis stabilization in the orbital frame from arbitrary initial tumbling conditions. The numerical study also shows that the proposed control algorithm outperforms a model-based Proportional–Derivative (PD) control in terms of pointing accuracy at the expense of higher energy consumption....
Airport slot allocation is a key short-term solution to address airport capacity constraints, and it has long been a focus of research in the field of air traffic management. The existing studies primarily consider constraints such as airport capacity and flight operations, optimizing the slot allocation of arrival and departure flights to maximize the utilization of airport resources. This study proposes an airline fairness index based on a demandside value system and addresses the problem of flight slot allocation by developing a tri-objective model. The model simultaneously considers the maximum slot deviation, total slot deviation, and airline fairness. Additionally, dynamic capacity constraints using rolling time windows and constraints on slot migration during peak periods are incorporated. The ε-constraint method is employed in conjunction with a large-neighborhood search heuristic to solve a two-stage optimization process, yielding an efficient allocation scheme. The experimental results show that the introduction of rolling capacity constraints effectively resolves the issue of continuous overcapacity that arises when only a fixed capacity is considered. Additionally, the proposed airline fairness index, based on a demand-side value system, can significantly improve fairness during the slot allocation process. By sacrificing at most 16% of the total displacement, it is possible to reduce the unfairness index by nearly 80%....
Bolted connections are extensively utilized in aircraft structures, and accurately simulating these connections is a critical factor affecting the precision of vibration and noise response predictions for aircraft. This study focuses on an instrument compartment of a specific aircraft model, employing the virtual material method to simulate the bolted joints within the structure. Parameters for the virtual material layer were obtained through theoretical calculations combined with parameter identification methods, achieving precise modeling of the instrument compartment. By comparing the calculated modes with the experimental modes of the instrument compartment, it was found that the first four modal shapes from both calculation and experiment were completely consistent, with the error in natural frequencies within three percent. Subsequently, acoustic and vibration computations were performed using both the virtual material model and the tied constraint model, with comparisons made against experimental results. The findings indicate that the root mean square (RMS) acceleration response of the virtual material model was 11.23 g, closely matching the experimental value of 10.35 g. Additionally, the total sound pressure level inside the acoustic cavity was 136.98 dB, closely aligning with the experimental value of 135.76 dB. These results demonstrate that the virtual material method offers higher accuracy in structural acoustic and vibration calculations....
The focus of this paper is on some of the activities performed by CIRA under the framework of the HERWINGT project (Hybrid Electric RegionalWing Integration Novel Wing Technologies) supported by the Clean Aviation Joint Undertaking and funded by the European Union. The aim of the project is to design an innovative wing suitable for future hybrid electric regional aircraft (HER) that will contribute to the overall target of reducing fuel burn, CO2, and other GHG emissions by improving aerodynamic efficiency and reducing weight. The aerodynamic design of a high-lift system of wings in the form of a compliant morphing flap is presented in this paper. A morphing flap was designed through CIRA’s in-house-developed evolutionary optimization software employing the SU2 open source RANS flow solver. The required performances can be achieved by a configuration equipped with both flap and droop noses, with flow control applied to mitigate the separation occurring over the rear upper region of the wing section. This has become particularly important for landing performances. Analyses were conducted for a 2D wing section. Requirements for the flow control system in terms of mass flow and maximum extension of the separated region were formulated....
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