Results 61 to 70 of about 15,084 (235)

Pneumatic boot for helicopter rotor deicing [PDF]

open access: yes, 1981
Pneumatic deicer boots for helicopter rotor blades were tested. The tests were conducted in the 6 by 9 ft icing research tunnel on a stationary section of a UH-IH helicopter main rotor blade.
Blaha, B. J., Evanich, P. L.
core   +1 more source

A Review of Modeling and Control Techniques for Unmanned Aerial Vehicles

open access: yesEngineering Reports, Volume 7, Issue 6, June 2025.
By systematically classifying UAV modeling techniques and comparing control methods, this paper addresses a notable gap in the current literature. Furthermore, it highlights emerging trends and challenges in UAV control systems, providing valuable insights to guide future research toward enhancing the stability, efficiency, and adaptability of ...
Elisabeth Andarge Gedefaw   +2 more
wiley   +1 more source

MATHEMATICAL MODELS OF THE RADAR SIGNAL REFLECTED FROM A HELICOPTER MAIN ROTOR IN APPLICATION TO INVERSE SYNTHESIS OF ANTENNA APERTURE

open access: yesИзвестия высших учебных заведений России: Радиоэлектроника, 2019
Introduction. The basis for solving the problem of aircraft recognition is the formation of radar portraits, reflecting the constructive features of aerial vehicles.
Sergey R. Heister, Thai T. Nguyn
doaj   +1 more source

Continuous Adjoint to Proudman's Formula for Aeroacoustic Shape Optimization

open access: yesInternational Journal for Numerical Methods in Fluids, Volume 97, Issue 6, Page 966-984, June 2025.
This paper presents a cost‐efficient framework for aeroacoustic shape optimization by developing the adjoint to Proudman's formula, coupled with the steady‐state RANS equations and the k‐ ω$$ \omega $$ SST turbulence model. The aeroacoustic model and the adjoint solver are initially validated/verified with experimental data/finite differences, before ...
M. Erfan Farhikhteh   +2 more
wiley   +1 more source

Development of an unsteady aerodynamics model to improve correlation of computed blade stresses with test data [PDF]

open access: yes, 1985
A reliable rotor aeroelastic analysis operational that correctly predicts the vibration levels for a helicopter is utilized to test various unsteady aerodynamics models with the objective of improving the correlation between test and theory.
Gangwani, S. T.
core   +1 more source

Numerical Study of the Active Flow Control Effect on the Wind Turbine Blade Section Using a Trailing Edge Flap

open access: yesWind Energy, Volume 28, Issue 6, June 2025.
ABSTRACT Wind turbines operating in unsteady and complex environments often encounter asymmetric and unsteady vortex flows on the suction side of the blade, leading to airflow separation and dynamic stall. These issues significantly impact the aerodynamic performance and energy efficiency of wind turbines. Trailing edge flaps are an active flow control
S. U. N. ZhiXin   +2 more
wiley   +1 more source

A rotor-mounted digital instrumentation system for helicopter blade flight research measurements [PDF]

open access: yes
A rotor mounted flight instrumentation system developed for helicopter rotor blade research is described. The system utilizes high speed digital techniques to acquire research data from miniature pressure transducers on advanced rotor airfoils which are ...
Haywood, W. S., Jr.   +2 more
core   +1 more source

A CFD Simulation‐Based High‐Fidelity Database for Data‐Driven Wake Model Considering Wind Farm Active Yaw Control

open access: yesWind Energy, Volume 28, Issue 5, May 2025.
ABSTRACT A thorough understanding of turbine wakes is essential for various aspects of wind energy, including turbine siting, load evaluation, and wind farm control. However, high‐fidelity time‐domain computational fluid dynamics (CFD) simulations that consider all possible turbulent inflow wind conditions are computationally expensive and impractical ...
Wenhao Xu, Gaohua Li, Feng Guo, Zhen Gao
wiley   +1 more source

Thrust pulsation of coaxial main rotor, caused by the blades relative position

open access: yesНаучный вестник МГТУ ГА, 2020
The influence of reciprocal position of the upper rotor blades in respect to the lower rotor blades is characteristic for coaxial main rotor. It is established that the initial azimuth of the blade, for example, of the upper rotor’s which does not ...
B. S. Kritsky   +3 more
doaj   +1 more source

Helicopter far-field acoustic levels as a function of reduced main-rotor advancing blade-tip Mach number [PDF]

open access: yes
During the design of a helicopter, the weight, engine, rotor speed, and rotor geometry are given significant attention when considering the specific operations for which the helicopter will be used. However, the noise radiated from the helicopter and its
Lemasurier, Philip   +2 more
core   +1 more source

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