scholarly journals Sound power spectra modelling of the vehicle in motion equipped with rotary-screw propulsion unit

2019 ◽  
Vol 1177 ◽  
pp. 012034
Author(s):  
Y Molev ◽  
D Mokerov ◽  
S Ivanov ◽  
M Saushkina ◽  
Y Palutin
Keyword(s):  
Power Spectra ◽  
Sound Power ◽  
Propulsion Unit ◽  
Rotary Screw

Changes in breath sound power spectra during experimental oleic acid-induced lung injury in pigs

2014 ◽  
Vol 116 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Jukka Räsänen ◽  
Michael E. Nemergut ◽  
Noam Gavriely
Keyword(s):  
Acute Lung Injury ◽  
Oleic Acid ◽  
Gas Exchange ◽  
Lung Injury ◽  
Power Spectra ◽  
Lung Mechanics ◽  
Sound Power ◽  
Frequency Spectra ◽  
Mechanically Ventilated ◽  
Breath Sounds

To evaluate the effect of acute lung injury on the frequency spectra of breath sounds, we made serial acoustic recordings from nondependent, midlung and dependent regions of both lungs in ten 35- to 45-kg anesthetized, intubated, and mechanically ventilated pigs during development of acute lung injury induced with intravenous oleic acid in prone or supine position. Oleic acid injections rapidly produced severe derangements in the gas exchange and mechanical properties of the lung, with an average increase in venous admixture from 16 ± 12 to 62 ± 16% ( P < 0.01), and a reduction in dynamic respiratory system compliance from 25 ± 4 to 14 ± 4 ml/cmH2O ( P < 0.01). A concomitant increase in sound power was seen in all lung regions ( P < 0.05), predominantly in frequencies 150–800 Hz. The deterioration in gas exchange and lung mechanics correlated best with concurrent spectral changes in the nondependent lung regions. Acute lung injury increases the power of breath sounds likely secondary to redistribution of ventilation from collapsed to aerated parts of the lung and improved sound transmission in dependent, consolidated areas.

Influence of Pavement Roughness on Tire Noise

1999 ◽  
Author(s):  
Richard J. Ruhala ◽  
Courtney B. Burroughs
Keyword(s):  
Power Spectra ◽  
Leading Edge ◽  
Sound Power ◽  
Acoustic Intensity ◽  
Radiated Noise ◽  
Tire Noise ◽  
Pavement Roughness ◽  
Different Types ◽  
Acoustical Holography ◽  
Nearfield Acoustical Holography

Abstract In this study, the influence of the levels of pavement roughness on tire noise is examined using Nearfield Acoustical Holography (NAH) to measure noise from single tires mounted on a two-wheel trailer towed over different types of pavements. Contributions to the radiated noise from the leading edge, trailing edge, and sidewall of two tires are identified. Two experimental tires — a blank tire and a monopitch tire — are evaluated on three pavements — smooth asphalt, stud-damaged concrete, and Ellsworth — at 56 km/hr. From the measured complex pressure, acoustic intensity is reconstructed on side plane of the tires using NAH procedures. Additionally, sound power spectra levels are presented. Tire noise generating mechanisms associated with each pavement are inferred from measurements. The experimental results are compared with theories on pavement-induced tire noise available in the literature.

Sound‐Power Spectra from Subsonic Jets

1964 ◽  
Vol 36 (10) ◽  
pp. 2012-2013
Author(s):  
Norman E. Barnett
Keyword(s):  
Power Spectra ◽  
Sound Power

scholarly journals Modelling of vehicles with rotary-screw propulsion unit along water-flooded substructure

2019 ◽  
Vol 1177 ◽  
pp. 012039
Author(s):  
A Strizhak ◽  
U Vakhidov ◽  
A Lipin ◽  
R Dorofeev ◽  
A V Sogin ◽  
...  
Keyword(s):  
Propulsion Unit ◽  
Rotary Screw

scholarly journals Effect of PEEP on breath sound power spectra in experimental lung injury

2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Jukka Räsänen ◽  
Michael E Nemergut ◽  
Noam Gavriely
Keyword(s):  
Lung Injury ◽  
Power Spectra ◽  
Breath Sound ◽  
Sound Power

Towards a Universal Scaling for Broadband Turbulent Noise in Internal Flow Devices

2013 ◽  
Author(s):  
Arjen de Jong ◽  
Joachim Golliard
Keyword(s):  
High Speed ◽  
Scaling Laws ◽  
Scaling Law ◽  
Power Spectra ◽  
Internal Flow ◽  
Acoustic Power ◽  
Broadband Noise ◽  
Current Work ◽  
Sound Power ◽  
Noise Sources

An investigation is performed on the scalability of broadband noise sources from separated flows in internal pipe systems. Broadband sources from for example wellhead chokes, bends and valves can potentially excite subsea manifolds through fluid acoustic coupling and fluid structural coupling. The focus of the current work is evaluation and improvement of scaling laws for collapse of sound power spectra. The approach proposed here is to use steady-state Computational Fluid Dynamics [CFD] to better estimate the properties of the flow in order to improve the scaling law and obtain a universal broadband spectrum. Steady Reynolds Averaged Navier-Stokes [RANS] simulations of several bend and orifice geometries have been performed. A surface acoustic power model based on modeled turbulent quantities is implemented. Based on the RANS data, more advanced models for scaling have been developed. Experimental sound power spectra from literature of the simulated geometries are scaled using different methodologies in both amplitude and frequency. When a new scaling based on CFD modeled surface acoustic power was used, a universal collapse among geometries occurred. Using CFD, the velocity in the high-speed sound-producing region is obtained, as well as a more accurate length scaling in order to improve the frequency scaling. A vast improvement in collapse over different geometries is achieved. The current work indicates that a universal collapse might indeed be present. The methodology does not require high fidelity calculations and is thus easy to implement. By comparing original and new scaling laws, it turns out that the ratio of fluctuating drag over steady drag can vary among geometries.

scholarly journals Sound Generation under Rotary-Screw Propulsion Unit Base Cylinder Bending

2019 ◽  
Vol 695 ◽  
pp. 012027
Author(s):  
I. A. Erasov ◽  
I.G. Kuklina ◽  
Y.I. Molev ◽  
D.S. Mokerov ◽  
T.G. Skrebneva
Keyword(s):  
Sound Generation ◽  
Propulsion Unit ◽  
Rotary Screw
Sign in / Sign up

Export Citation Format

Share Document