Excitation by Flow Over an Obstructed Opening

2002 ◽  
Author(s):  
Paul J. Zoccola
Keyword(s):  
Flow Field ◽  
Resonant Excitation ◽  
Cavity Resonance ◽  
Length Scale ◽  
Cavity Pressure ◽  
Production Distribution ◽  
Cavity Opening ◽  
Large Length ◽  
Flow Over A Cavity ◽  
Large Length Scale

The effect on flow-induced cavity resonance of the presence of an obstruction, or a grid made up of regularly spaced obstructions, in the cavity opening is considered. The presence of a single obstruction or of a grid generally alters the flow so that the excitation occurs on the smaller length scale created by the obstruction. However, discussion of resonant excitation on the length scale encompassing the obstructions has not been found in the literature. For this study, measurements of cavity pressure due to flow over a cavity with obstructions or grids of varying dimensions in the opening were made. Measurements of the flow field around a single obstruction were also made. The cavity pressure measurements show that flow over an opening with a grid does result in the occurrence of classical resonant excitation at the large length scale. The frequency of the excitation and the amplitude of the response at the large length scale are reduced, depending on the dimensions of the obstruction. Flow field results show the effects that an obstruction has on the flow, including effects on the vortex convection velocity and the energy production distribution.

An Experimental Investigation of Flow-Induced Cavity Resonance

2001 ◽  
Author(s):  
Paul J. Zoccola ◽  
Theodore M. Farabee
Keyword(s):  
Experimental Investigation ◽  
Energy Production ◽  
Pressure Fluctuations ◽  
Cavity Resonance ◽  
Cavity Pressure ◽  
Novel Technique ◽  
Cavity Opening ◽  
The Mean ◽  
Marine Applications ◽  
Opening Phase

Abstract Excitation of cavity resonance by flow over an aperture is often a source of unwanted noise in aerospace, automotive, and marine applications. An experimental investigation of this phenomenon was conducted. Detailed measurements of the cavity pressure and the velocity field in the opening were performed in a quiet flow facility. Spectral data on cavity pressure fluctuations obtained for a variety of configurations were analyzed over a range of speeds to determine the behavior of both sheartones and cavity tones during non-resonant and resonant conditions. The mean and fluctuating velocity profiles as well as the cross-spectral properties between the velocity components and cavity pressure were also obtained within the cavity opening. Phase between the velocity components and the pressure was used to calculate the streamwise convection velocities across the opening. A novel technique used to measure vorticity allowed calculation of the measured energy production in the opening. The data support the finding that the resonant and non-resonant conditions are distinguished by the behavior of the convection velocity and by the distribution of energy production in the flow field.

Small-to-Large Length Scale Transition of TMAO Interaction with Hydrophobic Solutes

2021 ◽  
Author(s):  
Angelina Folberth ◽  
Swaminath Bharadwaj ◽  
Nico van der Vegt
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Md Simulations ◽  
Free Energy Calculations ◽  
Length Scale ◽  
Simulation Data ◽  
Energy Calculations ◽  
Large Length ◽  
Hydrophobic Solutes ◽  
Large Length Scale

We report the effect of trimethylamine N-oxide (TMAO) on the solvation of nonpolar solutes in water studied with molecular dynamics (MD) simulations and free-energy calculations. The simulation data indicate the...

scholarly journals Chemical Inhomogeneities in Galaxies

1977 ◽  
Vol 45 ◽  
pp. 67-71 ◽  
Author(s):  
M. G. Edmunds
Keyword(s):  
Interstellar Medium ◽  
Chemical Evolution ◽  
Galactic Disk ◽  
Observational Evidence ◽  
Galactic Evolution ◽  
Length Scale ◽  
Galactic Chemical Evolution ◽  
Large Length ◽  
Large Length Scale

The local chemical inhomogneity of the interstellar medium at a given time is an important factor in models of galactic chemical evolution. It can affect both the G-dwarf metallicity problem (Tinsley 1975, Talbot and Arnett 1973) and the correlation of the abundances of different elements (Tinsley 1976). Observational evidence of abundance gradients in our own Galaxy, and someothergalaxies (summarised by Peimbert 1975, van den Bergh 1975), implies that in homogeneities over a large length scale must be created and survive during galactic evolution. Brief consideration of the mixing of the Galactic disk (e.g. Edmunds 1975, 1976) suggests

Influence of Surface Silanization on the Physicochemical Stability of Silver Nanocoatings: A Large Length Scale Assessment

2017 ◽  
Vol 121 (21) ◽  
pp. 11300-11311 ◽  
Author(s):  
Victor T. Noronha ◽  
Francisco A. Sousa ◽  
Antonio G. Souza Filho ◽  
Cristiane A. Silva ◽  
Francisco A. Cunha ◽  
...  
Keyword(s):  
Length Scale ◽  
Scale Assessment ◽  
Physicochemical Stability ◽  
Large Length ◽  
Large Length Scale

scholarly journals Spin-Hall Voltage over a Large Length Scale in Bulk Germanium

2017 ◽  
Vol 118 (16) ◽  
Author(s):  
F. Bottegoni ◽  
C. Zucchetti ◽  
S. Dal Conte ◽  
J. Frigerio ◽  
E. Carpene ◽  
...  
Keyword(s):  
Length Scale ◽  
Hall Voltage ◽  
Large Length ◽  
Large Length Scale

STUDY OF A PAIR OF COUPLED CONTINUUM EQUATIONS MODELING SURFACE GROWTH: INTERPLAY BETWEEN SURFACE DIFFUSION, DESORPTION-ACCRETION AND SCHWOEBEL BACK DIFFUSION

2004 ◽  
Vol 18 (10n11) ◽  
pp. 1549-1569
Author(s):  
AIN-UL HUDA ◽  
OMJYOTI DUTTA ◽  
ABHIJIT MOOKERJEE
Keyword(s):  
Surface Diffusion ◽  
Numerical Data ◽  
Length Scale ◽  
Back Diffusion ◽  
Mbe Growth ◽  
Crossover Behavior ◽  
Long Time ◽  
Large Length ◽  
Large Length Scale ◽  
Insight Into

In this communication we shall focus on the three microscopic processes whose interplay determine the surface morphology of MBE growth: namely, surface diffusion, desorption and accretion and Schwoebel back diffusion. We gain insight into the dynamics of growth via one-loop perturbative techniques. This allows us to analyze our numerical data. We conclude that there is a crossover behavior from a roughening regime to a very long-time, large length scale smoothening regime.

Sign in / Sign up

Export Citation Format

Share Document