Results 81 to 90 of about 94,319 (292)
Helicopter main-rotor noise: Determination of source contributions using scaled model data [PDF]
Acoustic data from a test of a 40 percent model MBB BO-105 helicopter main rotor are scaled to equivalent full-scale flyover cases. The test was conducted in the anechoic open test section of the German-Dutch Windtunnel (DNW).
Brooks, Thomas F. +2 more
core +1 more source
CAA Modeling of Helicopter Main Rotor in Hover [PDF]
, 2017 In this work rotor aeroacoustics in hover is considered. Farfield observers are used and the nearfield flow parameters are obtained using the in house HMB and commercial Fluent CFD codes (identical hexa-grids are used for both solvers). Farfield noise at
Barakos, George +5 more
core +2 more sources
Lubrication Science, EarlyView.ABSTRACT Porous gas bearings (PGBs) enable high‐speed, oil‐free operation in modern rotating machinery. This study develops a coupled thermo‐hydrodynamic (THD) model for a cylindrical porous gas bearing lubricated with four working fluids—air, R‐134a, helium and hydrogen.
S. Bechiri, B. Bouchehit, B. Bou‐Saïd
wiley +1 more source
Reduction of high-speed impulsive noise by blade planform modification of a model helicopter rotor [PDF]
The reduction of high speed impulsive noise for the UH-1H helicopter was investigated by using an advanced main rotor system. The advanced rotor system had a tapered blade planform compared with the rectangular planform of the standard rotor system ...
Conner, D. A., Hoad, D. R.
core +1 more source
First 20 Years of Orbitrap Mass Spectrometry as the Mainstream Analytical Technique
Mass Spectrometry Reviews, EarlyView.ABSTRACT This review traces the first 20 years of Orbitrap mass spectrometry as a mainstream high‑resolution and accurate‑mass (HR/AM) technology. It outlines the historical development of the Orbitrap analyzer, the evolution of major instrument families, and the key technological innovations that enabled its widespread adoption. Particular emphasis is
Alexander Makarov
wiley +1 more source
Macromolecular Symposia, EarlyView.ABSTRACT This paper presents theoretical aspects and experimental tests for the design and optimization of a novel ducted fan propulsion system, complemented by multi‐element wings inspired by Handley Page and the aerodynamic Channel Wing concept.
Adrian Niță +4 more
wiley +1 more source
Zhongguo Jianchuan YanjiuObjectiveUnsteady forces generated by pump-jet rotors are a key factor affecting the vibration and noise levels of underwater vehicles. These forces not only induce structural vibrations through coupling between the propeller, shafting, and hull systems,
Wanghao TANG, Junjie XU, Xiuchang HUANG
doaj +1 more source
Results of the 1986 NASA/FAA/DFVLR main rotor test entry in the German-Dutch wind tunnel (DNW) [PDF]
An acoustics test of a 40%-scale MBB BO-105 helicopter main rotor was conducted in the Deutsch-Niederlandischer Windkanal (DNW). The research, directed by NASA Langley Research Center, concentrated on the generation and radiation of broadband noise and ...
Brooks, Thomas F., Martin, Ruth M.
core +1 more source
Nonlinear Vibration Characteristic Analysis of Electric Vehicle–Road Coupling System
International Journal of Mechanical System Dynamics, EarlyView.ABSTRACT In‐wheel motor drive is the developing direction of automobile electrification and intelligence. However, the increased unsprung mass in in‐wheel motor‐driven electric vehicles (IWMEVs) leads to higher dynamic tire loads, thereby intensifying vehicle–road coupling interactions. To address this problem, an 11‐degree‐of‐freedom nonlinear dynamic
Guizhen Feng, Shaohua Li, Xuewei Wang
wiley +1 more source
Numerical Study on Dual-Rotor Phase Synchronization for Tonal Noise Counteraction
Aerospace Research CommunicationsUrban Air Mobility (UAM) is considered as a powerful way to relieve urban congestion, but the noise problem is still a major obstacle to its wide application.
Ziang Chai, Xiaodong Li, Hua-Dong Yao
doaj +1 more source