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Портал Begell Электронная Бибилиотека e-Книги Журналы Справочники и Сборники статей Коллекции
International Journal of Fluid Mechanics Research
ESCI SJR: 0.206 SNIP: 0.446 CiteScore™: 0.5

ISSN Печать: 2152-5102
ISSN Онлайн: 2152-5110

Выпуски:
Том 47, 2020 Том 46, 2019 Том 45, 2018 Том 44, 2017 Том 43, 2016 Том 42, 2015 Том 41, 2014 Том 40, 2013 Том 39, 2012 Том 38, 2011 Том 37, 2010 Том 36, 2009 Том 35, 2008 Том 34, 2007 Том 33, 2006 Том 32, 2005 Том 31, 2004 Том 30, 2003 Том 29, 2002 Том 28, 2001 Том 27, 2000 Том 26, 1999 Том 25, 1998 Том 24, 1997 Том 23, 1996 Том 22, 1995

International Journal of Fluid Mechanics Research

DOI: 10.1615/InterJFluidMechRes.v31.i5.40
pages 456-476

On Generation of Tonal Sound Vibrations by Airflow in Stenotic Airways

V. G. Basovsky
Institute of Hydromechanics of National Academy of Sciences of Ukraine, Kyiv, Ukraine
I. V. Vovk
Institute of Hydromechanics of National Academy of Sciences of Ukraine, Kyiv, Ukraine
O. I. Vovk
Institute of Hydromechanics of National Academy of Sciences of Ukraine, Kyiv, Ukraine

Краткое описание

A hypothesis about one of possible mechanisms of occurrence of wheezes (tonal sound signals) in a human bronchial tree at its pathologies is put forward. It is supposed that viscous sputum allocated in affected airways, can form aerodynamic structures of the nozzle-jet-obstacle type. A stenosis forming a high-speed jet plays the role of a nozzle in the act of breathing. The other stenosis, bifurcation of the airways or the sputum formations can play the role of an obstacle. An experimental installation was used to check the mentioned hypothesis. It included a physical model of an airway along with the equipment for recording and processing of the sound signals and for estimation of the airflow velocity. As a result of experiments it was shown that presence of the specified aerodynamic structures can provide an efficient transformation of energy of the stream in airways into energy of the sound vibrations, which spectra are very similar to those of wheezes. A number of laws, being characteristic for the considered structures, is established. The threshold values of flow velocities when the tonal sound vibrations start to arise are estimated. It is shown that the relative distance between a stenosis forming a jet and an obstacle being increased, the threshold Reynolds numbers and the threshold frequencies of the tonal signals tend to a decrease, and the threshold Strouhal numbers - to an increase.