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%2F68407700%3A21220%2F16%3A00329565" target="_blank" >RIV/68407700:21220/16:00329565 - 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 similar to 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 similar to 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

D - Stať ve sborníku

CEP obor

—

OECD FORD obor

20302 - Applied mechanics

Projekt

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

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2016

Kód důvěrnosti údajů

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

Název statě ve sborníku

EFM15 - Experimental Fluid Mechanics 2015

ISBN

—

ISSN

2100-014X

e-ISSN

2100-014X

Počet stran výsledku

10

Strana od-do

—

Název nakladatele

EDP Sciences

Místo vydání

Les Ulis Cedex A

Místo konání akce

Praha

Datum konání akce

17. 11. 2015

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

000400395300008