A numerical study on near-field pressure fluctuations of symmetrical and anti-symmetrical flapping modes of twin-jet using a high-resolution shock-capturing scheme

2021 ◽  
Vol 119 ◽  
pp. 107147
Author(s):  
Myeonghwan Ahn ◽  
Duck-Joo Lee ◽  
Mihai Mihaescu
Keyword(s):  
High Resolution ◽  
Numerical Study ◽  
Near Field ◽  
Pressure Fluctuations ◽  
Shock Capturing

Numerical study of acoustic radiation due to a supersonic turbulent boundary layer

2014 ◽  
Vol 746 ◽  
pp. 165-192 ◽  
Author(s):  
Lian Duan ◽  
Meelan M. Choudhari ◽  
Minwei Wu
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Numerical Simulations ◽  
Surface Pressure ◽  
Free Stream ◽  
Acoustic Radiation ◽  
Numerical Study ◽  
Near Field ◽  
Pressure Fluctuations ◽  
Spatial Coherence

AbstractDirect numerical simulations are used to examine the pressure fluctuations generated by fully developed turbulence in a Mach 2.5 turbulent boundary layer, with an emphasis on the acoustic fluctuations radiated into the free stream. Single- and multi-point statistics of computed surface pressure fluctuations show good agreement with measurements and numerical simulations at similar flow conditions. Consistent with spark shadowgraphs obtained in free flight, the quasi-homogeneous acoustic near field in the free-stream region consists of randomly spaced wavepackets with a finite spatial coherence. The free-stream pressure fluctuations exhibit important differences from the surface pressure fluctuations in amplitude, frequency content and convection speeds. Such information can be applied towards improved modelling of boundary layer receptivity in conventional supersonic facilities and, hence, enable a better utilization of transition data acquired in such wind tunnels. The predicted acoustic characteristics are compared with the limited available measurements. Finally, the numerical database is used to understand the acoustic source mechanisms, with the finding that the supersonically convecting eddies that can directly radiate to the free stream are confined to the buffer zone within the boundary layer.

scholarly journals Experimental and numerical study of rotor aeroacoustics

2017 ◽  
Vol 16 (6) ◽  
pp. 460-475 ◽  
Author(s):  
Robert Stepanov ◽  
Vladimir Pakhov ◽  
Andrey Bozhenko ◽  
Andrey Batrakov ◽  
Lyaysan Garipova ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Resolution ◽  
Numerical Study ◽  
Near Field ◽  
Far Field ◽  
Acoustic Data ◽  
Technical University ◽  
Helicopter Acoustics

The work documents recent experiments at the Kazan National Research Technical University named after A.N. Tupolev (Kazan Aviation Institute), related to helicopter acoustics. The objective is to measure nar-field acoustics of rotors in hover and provide data suitable for computational fluid dynamics validation. The obtained set of data corresponds to a scaled rotor of known planform and the results are of high resolution. An advantage of the current dataset is that direct near-field acoustic data is made available and this allows for easy and direct comparisons with computational fluid dynamics predictions, without the need to use far-field aeroacoustic methods.

High-resolution deep-UV laser mask repair based on near-field optical technology

1996 ◽  
Author(s):  
Klony S. Lieberman ◽  
Hanan Terkel ◽  
Michael Rudman ◽  
A. Ignatov ◽  
Aaron Lewis
Keyword(s):  
High Resolution ◽  
Near Field ◽  
Uv Laser ◽  
Optical Technology ◽  
Deep Uv

Numerical study on near-field characteristics of landslide-generated impulse waves in channel reservoirs

2021 ◽  
Vol 595 ◽  
pp. 126012
Author(s):  
Xiaoliang Wang ◽  
Chuanqi Shi ◽  
Qingquan Liu ◽  
Yi An
Keyword(s):  
Numerical Study ◽  
Near Field ◽  
Impulse Waves

Design of high-resolution near-field focusing metasurface lens

2021 ◽  
pp. 1-10
Author(s):  
Jiang Li ◽  
Zhu Wang ◽  
Yue Ma ◽  
Xuehong Ran ◽  
Honggang Hao
Keyword(s):  
High Resolution ◽  
Near Field

High resolution scanning near field mapping of enhancement on SERS substrates: comparison with photoemission electron microscopy

2016 ◽  
Vol 18 (14) ◽  
pp. 9405-9411 ◽  
Author(s):  
C. Awada ◽  
J. Plathier ◽  
C. Dab ◽  
F. Charra ◽  
L. Douillard ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Near Field ◽  
Spectroscopic Technique ◽  
Proof Of Concept ◽  
Sers Substrates ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Photoemission Electron

The need for a dedicated spectroscopic technique with nanoscale resolution to characterize SERS substrates pushed us to develop a proof of concept of a functionalized tip–surface enhanced Raman scattering (FTERS) technique.

Sign in / Sign up

Export Citation Format

Share Document