Article
Geosciences, Multidisciplinary
R. Yoshimura, J. Ito, P. A. Schittenhelm, K. Suzuki, A. Yakeno, S. Obayashi
Summary: A clear air turbulence (CAT) occurred over Tokyo, Japan on December 30, 2020, largely generated by breaking Kelvin-Helmholtz instability waves. A regional numerical weather prediction model with fine resolution was used to simulate the event, which was validated using onboard-recorded flight data and a flight simulation. The reproduced strong turbulence locations matched well with the regions where turbulence was encountered by flights on that day. The simulation with the finest resolution successfully resolved the Kelvin-Helmholtz waves and their breaking, resulting in stronger turbulent eddies with meteorological effects on the airplanes. The response of a virtual airplane to the simulated turbulence was estimated through flight simulation, and the comparison between onboard-recorded data and virtual flight data confirmed the reasonable reproduction of turbulent eddies.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Engineering, Aerospace
Xinying Liu, Anna Aba, Pierluigi Capone, Leonardo Manfriani, Yongling Fu
Summary: The concept of a new energy management system that combines meteorological and orographic influences on airplane safety envelope has been developed and implemented at the ZHAW Centre for Aviation. A flight simulation environment was built to test the cockpit display system, and pilot-in-the-loop flight simulations were conducted. The study focused on a small mountainous region in Switzerland and used a large-eddy simulation model to generate highly resolved wind fields.
Article
Engineering, Aerospace
Honglei Ji, Linghai Lu, Mark D. White, Renliang Chen
Summary: This paper proposes a new pilot model to investigate the effect of turbulent wind on rotorcraft handling qualities. The model consists of three components and is validated through simulation. The results demonstrate that the model can plan and track desired trajectories and predict handling qualities by modeling the effect of the vestibular system.
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Guozhi Li, Yihua Cao
Summary: In this article, a degeneration method of inverse simulation is proposed for a helicopter system to analyze pull-up and slalom maneuvers. The method is compared with flight test data and reference data, showing its accuracy and effectiveness. Unlike conventional inverse simulation methods, it improves numerical stability by degenerating the system of first-order differential equations into nonlinear equations to solve the output vector in each simulation time step.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Aerospace
Yuqing Qiu, Yan Li, Jinxi Lang, Zhong Wang
Summary: This paper analyzes the dynamic characteristics of coaxial high-speed helicopters (CHHs) in transition mode and proposes a unified Decoupled Allocation Transition Control (DATC) method to achieve stable flight and improved handling quality. The control architecture is designed using explicit model following (EMF) and classical control techniques with a T-S fuzzy model-based parameter scheduling mechanism, considering actuator saturation. Numerical simulations demonstrate the feasibility and performance of the proposed transition flight control laws.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Optics
Zhangrong Mei, Olga Korotkova, Daomu Zhao, Yonghua Mao
Summary: A class of wide-stationary optical sources with a specially designed degree of coherence profile is introduced for radiating spectral densities with a controllable vortex. This is achieved by modeling the source coherence state as a combination of helicoidal separable phase and a Cartesian phase factor.
Article
Engineering, Aerospace
Abdallah Dayhoum, Mohamed Y. Zakaria, Omar E. Abdelhamid
Summary: Experiments are conducted on a small-scale RC helicopter in both hovering and forward flight modes. An open wind tunnel is used to provide forward airflow for the helicopter model. A test rig is designed to measure thrust in both hovering and forward flight. The helicopter is controlled using a graphical user interface program and sensors. Measurements are taken for different speeds and angles in both hovering and forward flight modes. The results can be used for rotor sizing of small helicopters.
JOURNAL OF AEROSPACE ENGINEERING
(2023)
Article
Engineering, Aerospace
Ying-Chih Lai, Tri-Quang Le
Summary: This article presents the development of an autonomous flight control system for a small-scale unmanned helicopter based on an online adaptive learning-based observer and model predictive control. By integrating various methods, the stability and performance of the flight control system have been improved significantly.
IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
(2021)
Article
Engineering, Aerospace
Hao Zhang, Rui Zhao, Chih-Yung Wen
Summary: Numerical investigation was conducted on in-flight ice accretion on typical pitot-static systems, revealing that ambient temperature has a significant impact on icing-induced failure time, while blocking time is linearly proportional to wall temperature. With increasing inflow velocity, different variations in ice accretion were observed. Additionally, an increase in angle of attack accelerates failure under icing conditions.
INTERNATIONAL JOURNAL OF AEROSPACE ENGINEERING
(2021)
Article
Environmental Sciences
Manman Xu, Shiyong Shao, Ningquan Weng, Qing Liu
Summary: This paper analyzes data to propose a new statistical model for reconstructing atmospheric turbulence characteristics in the South China Sea. The reliability of the data is verified through comparison. The vertical distribution and seasonal variation of turbulence strength are analyzed, and the Richardson number is used to estimate the probability of optical turbulence. The research results show good consistency between different parameters.
Article
Mechanics
Petronio A. S. Nogueira, Pierluigi Morra, Eduardo Martini, Andre V. G. Cavalieri, Dan S. Henningson
Summary: This study analyzes the nonlinear terms in turbulent Couette flow at Reynolds number 400 and establishes a quantitative relationship between the covariance matrices of velocity and forcing through the resolvent operator. The dominance of certain nonlinear terms in predicting the statistical properties of streamwise vortices and streaks, as well as the coherent structure of forcing at low frequencies, is observed as key features of the flow. Constructive and destructive interferences between different forcing components greatly modify the flow response, illustrating the importance of forcing 'colour' in this context.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Mechanical
Lennon F. Araujo, Cleverson Bringhenti, Luiz H. L. Whitacker, Jesuino T. Tomita, Jose Marcio P. Figueira
Summary: In this study, a computer model was developed to evaluate the performance of a helicopter engine under different flight conditions. The model was adjusted to incorporate the specific factors of helicopter application and was compared with real flight test data.
JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING
(2022)
Article
Mechanics
Fujihiro Hamba
Summary: The non-local eddy diffusivity model shows potential in understanding and predicting scalar transport in turbulence, as validated and supported by direct numerical simulation data.
JOURNAL OF FLUID MECHANICS
(2022)
Review
Computer Science, Interdisciplinary Applications
Yihua Cao, Yihao Qin
Summary: This paper provides a systematic review of ship-helicopter dynamic interface simulation, focusing on modeling methods in airwake and flight simulation. It discusses turbulence models used in ship airwake simulation, as well as the modeling of atmospheric turbulence layer and ship motion effect. The paper also explores ship-helicopter coupling airwake simulation methods and summarizes CFD-based ship airwake models employed in flight simulation. It concludes with suggestions for future research in this field.
ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING
(2023)
Article
Mathematics
Honglei Ji, Linghai Lu, Renliang Chen
Summary: A moving spatial turbulence model is developed for rotorcraft maneuvering simulation, with synthetic simulation environment consisting of a flight dynamics model and a pilot model to demonstrate its effectiveness. The power spectral densities of both rotorcraft responses and pilot controls in turbulence are compared against flight test data to validate its performance.