Swirl flow stability: thermodynamic analysis and experiments

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388998%3A_____%2F24%3A00587629" target="_blank" >RIV/61388998:_____/24:00587629 - isvavai.cz</a>

Výsledek na webu

<a href="https://link.springer.com/article/10.1007/s00161-024-01303-6" target="_blank" >https://link.springer.com/article/10.1007/s00161-024-01303-6</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s00161-024-01303-6" target="_blank" >10.1007/s00161-024-01303-6</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Swirl flow stability: thermodynamic analysis and experiments

Popis výsledku v původním jazyce

The current paper presents a theoretical analysis of swirl flow stability, both inside a tube (vortex tube) and in a free annular swirl flow. The starting concept is the study of the evolution of velocity and temperature fluctuations. Methods of non-equilibrium thermodynamics are used to describe the magnitude of fluctuations and their properties. The important role of the total enthalpy follows from a variational analysis. Moreover, the thermodynamic criterion of the stability is formulated using the total enthalpy, and compared with experiments, numerical results and classical Rayleigh theory support its applicability. It was shown that the solid body vortex is at the margin of stability, which is experimentally observed. Analogously, the potential vortex is by the thermodynamic criterion stable, however, by the Rayleigh criteria it is on the onset of stability. The classical Taylor experiment of flowbetween two rotating cylinders is analysed from the point of viewof this criterion. These results are underlined by swirl tube experiments at the Institute of Aerospace Thermodynamics at Stuttgart University and the annular nozzle experiments performed in the Institute of Thermomechanics CAS in Prague. Both independent experiments confirm the transformation of the initial annular vortex into a stable potential-type vortex. The results of this theory can also be used to explain the exceptional stability of tropical cyclones.

Název v anglickém jazyce

Swirl flow stability: thermodynamic analysis and experiments

Popis výsledku anglicky

The current paper presents a theoretical analysis of swirl flow stability, both inside a tube (vortex tube) and in a free annular swirl flow. The starting concept is the study of the evolution of velocity and temperature fluctuations. Methods of non-equilibrium thermodynamics are used to describe the magnitude of fluctuations and their properties. The important role of the total enthalpy follows from a variational analysis. Moreover, the thermodynamic criterion of the stability is formulated using the total enthalpy, and compared with experiments, numerical results and classical Rayleigh theory support its applicability. It was shown that the solid body vortex is at the margin of stability, which is experimentally observed. Analogously, the potential vortex is by the thermodynamic criterion stable, however, by the Rayleigh criteria it is on the onset of stability. The classical Taylor experiment of flowbetween two rotating cylinders is analysed from the point of viewof this criterion. These results are underlined by swirl tube experiments at the Institute of Aerospace Thermodynamics at Stuttgart University and the annular nozzle experiments performed in the Institute of Thermomechanics CAS in Prague. Both independent experiments confirm the transformation of the initial annular vortex into a stable potential-type vortex. The results of this theory can also be used to explain the exceptional stability of tropical cyclones.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20303 - Thermodynamics

Projekt

<a href="/cs/project/GC21-26232J" target="_blank" >GC21-26232J: Zvyšování přestupu tepla a hmoty v nestacionárních tekutinových proudech – využití vlivu hystereze, bistability a intermitence</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

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

Název periodika

Continuum Mechanics and Thermodynamics

ISSN

0935-1175

e-ISSN

1432-0959

Svazek periodika

36

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

20

Strana od-do

891-910

Kód UT WoS článku

001220307000001

EID výsledku v databázi Scopus

2-s2.0-85192708228