Jet flow issuing from an axisymmetric pipe-cavity-orifice nozzle

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388998%3A_____%2F16%3A00473462" target="_blank" >RIV/61388998:_____/16:00473462 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1051/epjconf/201611402006" target="_blank" >http://dx.doi.org/10.1051/epjconf/201611402006</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/epjconf/201611402006" target="_blank" >10.1051/epjconf/201611402006</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Jet flow issuing from an axisymmetric pipe-cavity-orifice nozzle

Popis výsledku v původním jazyce

An axisymmetric air jet flow is experimentally investigated under passive flow control. The jet issues from a pipe of the inner diameter and length of 10 mm and 150 mm which is equipped with an axisymmetric cavity at the pipe end. The cavity operates as a resonator creating self-sustained acoustic excitations of the jet flow. A mechanism of excitations is rather complex - in comparison with a common Helmholtz resonator. The experiments were performed using flow visualization, microphone measurements and time-mean velocity measurements by the Pitot probe. The power spectral density (PSD) and the sound pressure level (SPL) were evaluated from microphone measurements. The jet Reynolds number ranged Re = 1600-18 000. Distinguishable peaks in PSD indicated a function of the resonator. Because the most effective acoustic response was found at higher Re, a majority of experiments focused on higher Re regime. The results demonstrate effects of the passive control on the jet behavior. Fluid mixing and velocity decay along the axis is intensified. It causes shortening of the jet transition region. On the other hand, an inverse proportionality of the velocity decay (u ∼ 1/x) in the fully developed region is not changed. The momentum and kinetic energy fluxes decrease more intensively in the controlled jets in comparison with common jets.

Název v anglickém jazyce

Jet flow issuing from an axisymmetric pipe-cavity-orifice nozzle

Popis výsledku anglicky

An axisymmetric air jet flow is experimentally investigated under passive flow control. The jet issues from a pipe of the inner diameter and length of 10 mm and 150 mm which is equipped with an axisymmetric cavity at the pipe end. The cavity operates as a resonator creating self-sustained acoustic excitations of the jet flow. A mechanism of excitations is rather complex - in comparison with a common Helmholtz resonator. The experiments were performed using flow visualization, microphone measurements and time-mean velocity measurements by the Pitot probe. The power spectral density (PSD) and the sound pressure level (SPL) were evaluated from microphone measurements. The jet Reynolds number ranged Re = 1600-18 000. Distinguishable peaks in PSD indicated a function of the resonator. Because the most effective acoustic response was found at higher Re, a majority of experiments focused on higher Re regime. The results demonstrate effects of the passive control on the jet behavior. Fluid mixing and velocity decay along the axis is intensified. It causes shortening of the jet transition region. On the other hand, an inverse proportionality of the velocity decay (u ∼ 1/x) in the fully developed region is not changed. The momentum and kinetic energy fluxes decrease more intensively in the controlled jets in comparison with common jets.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

JU - Aeronautika, aerodynamika, letadla

OECD FORD obor

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Projekt

<a href="/cs/project/GA14-08888S" target="_blank" >GA14-08888S: Řízení proudových polí pomocí oscilací tekutiny</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

EPJ Web of Conferences

ISSN

2101-6275

e-ISSN

—

Svazek periodika

114

Číslo periodika v rámci svazku

March

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

10

Strana od-do

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Kód UT WoS článku

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EID výsledku v databázi Scopus

2-s2.0-84974815595