МОДЕЛЮВАННЯ ЗСУВНОГО І БЕЗЗСУВНОГО ПОТОКУ З ПЕРІОДИЧНОЮ ШВИДКІСНОЮ НЕСТАЦІОНАРНІСТЮ

The results of experimental modeling of shear and shearless flow with periodic velocity nonstationarity, organized using a generator of periodic wakes such as the "squirrel" cage, are presented. The purpose of this paper is to compare the structure of the flow behind the "squirrel&quo...

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Datum:2018
1. Verfasser: Suprun, T.T.
Format: Artikel
Sprache:Ukrainian
Veröffentlicht: Institute of Engineering Thermophysics of NAS of Ukraine 2018
Online Zugang:https://ihe.nas.gov.ua/index.php/journal/article/view/291
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Назва журналу:Thermophysics and Thermal Power Engineering

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Thermophysics and Thermal Power Engineering
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spelling oai:ojs2.ihenasgovua.s43.yourdomain.com.ua:article-2912018-12-14T18:58:03Z MODELLING OF SHEAR AND SHEARLESS FLOW WITH PERIODIC VELOCITY NONSTATIONARITY МОДЕЛЮВАННЯ ЗСУВНОГО І БЕЗЗСУВНОГО ПОТОКУ З ПЕРІОДИЧНОЮ ШВИДКІСНОЮ НЕСТАЦІОНАРНІСТЮ Suprun, T.T. The results of experimental modeling of shear and shearless flow with periodic velocity nonstationarity, organized using a generator of periodic wakes such as the "squirrel" cage, are presented. The purpose of this paper is to compare the structure of the flow behind the "squirrel" cages, as well as the analysis of the characteristics of the transition boundary layer for two different ways of locating the working surfaces: in the zone of the shearless core and shear periphery zone. The physical modelling of turbulized flow with velocity periodic nonstationarity is carried out in two experimental installations. It is shown that behind rotating “squirrel” cages there are two regions in the distributions of mean time velocities: the shearless flow core located in the center of “squirrel” cage and peripheral shear part. The aim of this paper is to compare the flow structure behind “squirrel” cages as well as to analyze the features of transient boundary layer for two different installations of working surfaces. The latter were flat plates installed on the different distances from the center of the “squirrel” cages: in the shearless flow core and in shear zone. Total longitudinal fluctuations are characterized by peaks reason of which is intersections of wakes. Behind the “squirrel” cages the levels of fluctuations decrease along the plates at x~100-600 mm from ~12 to 4,5% (II) and from ~6 to 3,5% (I). Despite the development of boundary layer happens under different external conditions (in uniform (I) and shear (II) flows), wake-induced transition takes place in both installations. Transformation of velocity profiles from pseudolaminar to turbulent is similar to one taking place in bypass transition. Distributions of total longitudinal fluctuations across the boundary layer differ by quantity of peaks and their intensity.  Today the physical modeling is one of the most perspective methods for studying transport processes under complex conditions. That is why the experimental investigations of periodic external flow structure are necessary for the further optimization of different equipment and their reliability enhancement. Представлены результаты экспериментального моделирования сдвигового и бессдвигового потока с периодической скоростной нестационарностью, организованной с помощью генератора периодических следов типа «беличье» колесо. Целью работы является сравнение структуры потока за «беличьими» колесами, а также анализ особенностей переходного пограничного слоя для двух различных способов расположения рабочих поверхностей: в зоне центрального бессдвигового ядра или периферийной сдвиговой зоны. Представлені результати експериментального моделювання зсувного і беззсувного потоку з періодичною швидкісною нестаціонарністю, організованою за допомогою генератору періодичних слідів типу «біляче» колесо. Метою роботи є порівняння структури потоку за «білячими» колесами, а також аналіз особливостей перехідного примежового шару для двох різних способів розташування робочих поверхонь: в зоні центрального беззсувного ядра або периферійної зсувної зони. Institute of Engineering Thermophysics of NAS of Ukraine 2018-06-20 Article Article application/pdf https://ihe.nas.gov.ua/index.php/journal/article/view/291 10.31472/ihe.2.2018.10 Thermophysics and Thermal Power Engineering; Vol 40 No 2 (2018): Industrial Heat Engineering; 72-77 Теплофизика и Теплоэнергетика; Vol 40 No 2 (2018): Industrial Heat Engineering; 72-77 Теплофізика та Теплоенергетика; Vol 40 No 2 (2018): Industrial Heat Engineering; 72-77 2663-7235 uk https://ihe.nas.gov.ua/index.php/journal/article/view/291/235 Copyright (c) 2018 Industrial Heat Engineering http://creativecommons.org/licenses/by/4.0
institution Thermophysics and Thermal Power Engineering
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datestamp_date 2018-12-14T18:58:03Z
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author Suprun, T.T.
spellingShingle Suprun, T.T.
МОДЕЛЮВАННЯ ЗСУВНОГО І БЕЗЗСУВНОГО ПОТОКУ З ПЕРІОДИЧНОЮ ШВИДКІСНОЮ НЕСТАЦІОНАРНІСТЮ
author_facet Suprun, T.T.
author_sort Suprun, T.T.
title МОДЕЛЮВАННЯ ЗСУВНОГО І БЕЗЗСУВНОГО ПОТОКУ З ПЕРІОДИЧНОЮ ШВИДКІСНОЮ НЕСТАЦІОНАРНІСТЮ
title_short МОДЕЛЮВАННЯ ЗСУВНОГО І БЕЗЗСУВНОГО ПОТОКУ З ПЕРІОДИЧНОЮ ШВИДКІСНОЮ НЕСТАЦІОНАРНІСТЮ
title_full МОДЕЛЮВАННЯ ЗСУВНОГО І БЕЗЗСУВНОГО ПОТОКУ З ПЕРІОДИЧНОЮ ШВИДКІСНОЮ НЕСТАЦІОНАРНІСТЮ
title_fullStr МОДЕЛЮВАННЯ ЗСУВНОГО І БЕЗЗСУВНОГО ПОТОКУ З ПЕРІОДИЧНОЮ ШВИДКІСНОЮ НЕСТАЦІОНАРНІСТЮ
title_full_unstemmed МОДЕЛЮВАННЯ ЗСУВНОГО І БЕЗЗСУВНОГО ПОТОКУ З ПЕРІОДИЧНОЮ ШВИДКІСНОЮ НЕСТАЦІОНАРНІСТЮ
title_sort моделювання зсувного і беззсувного потоку з періодичною швидкісною нестаціонарністю
title_alt MODELLING OF SHEAR AND SHEARLESS FLOW WITH PERIODIC VELOCITY NONSTATIONARITY
description The results of experimental modeling of shear and shearless flow with periodic velocity nonstationarity, organized using a generator of periodic wakes such as the "squirrel" cage, are presented. The purpose of this paper is to compare the structure of the flow behind the "squirrel" cages, as well as the analysis of the characteristics of the transition boundary layer for two different ways of locating the working surfaces: in the zone of the shearless core and shear periphery zone. The physical modelling of turbulized flow with velocity periodic nonstationarity is carried out in two experimental installations. It is shown that behind rotating “squirrel” cages there are two regions in the distributions of mean time velocities: the shearless flow core located in the center of “squirrel” cage and peripheral shear part. The aim of this paper is to compare the flow structure behind “squirrel” cages as well as to analyze the features of transient boundary layer for two different installations of working surfaces. The latter were flat plates installed on the different distances from the center of the “squirrel” cages: in the shearless flow core and in shear zone. Total longitudinal fluctuations are characterized by peaks reason of which is intersections of wakes. Behind the “squirrel” cages the levels of fluctuations decrease along the plates at x~100-600 mm from ~12 to 4,5% (II) and from ~6 to 3,5% (I). Despite the development of boundary layer happens under different external conditions (in uniform (I) and shear (II) flows), wake-induced transition takes place in both installations. Transformation of velocity profiles from pseudolaminar to turbulent is similar to one taking place in bypass transition. Distributions of total longitudinal fluctuations across the boundary layer differ by quantity of peaks and their intensity.  Today the physical modeling is one of the most perspective methods for studying transport processes under complex conditions. That is why the experimental investigations of periodic external flow structure are necessary for the further optimization of different equipment and their reliability enhancement.
publisher Institute of Engineering Thermophysics of NAS of Ukraine
publishDate 2018
url https://ihe.nas.gov.ua/index.php/journal/article/view/291
work_keys_str_mv AT supruntt modellingofshearandshearlessflowwithperiodicvelocitynonstationarity
AT supruntt modelûvannâzsuvnogoíbezzsuvnogopotokuzperíodičnoûšvidkísnoûnestacíonarnístû
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