Publication detail

Mitigation of swirling flow with a vortex rope by passive installations—Theory, simulations, and experiments

URBAN, O. KURKOVÁ, M. POCHYLÝ, F.

Czech title

Potlačení vířivého proudění s vírovým copem pomocí pasivních zařízení - teorie, simulace a experimenty

English title

Mitigation of swirling flow with a vortex rope by passive installations—Theory, simulations, and experiments

Type

journal article in Web of Science

Language

en

Original abstract

This work is focused on reduction of swirling in cases from hydraulic machinery and, thus, mitigation of instabilities associated with swirling flow. We study this problem analytically using the torque integral equation, numerically using computational fluid dynamics (CFD) simulations, and experimentally using a swirl generator that generates swirling flow approximating that in a draft tube of a hydro turbine operating at a part load, featuring an unsteady spiral vortex—the vortex rope. The analytical description elucidates the effect of different installations on the circumferential velocity. Unconventional conical perforated installations targeting at increasing the dissipation were proposed and tested. The rather unsatisfactory results led to proposing fins placed unconventionally away from the wall, closer to the diffuser axis, which were subsequently shown to be able to reliably suppress the unsteady vortex rope. Their effect is documented by an analysis of CFD results including the proper orthogonal decomposition as well as experimental observations and measurements.

English abstract

This work is focused on reduction of swirling in cases from hydraulic machinery and, thus, mitigation of instabilities associated with swirling flow. We study this problem analytically using the torque integral equation, numerically using computational fluid dynamics (CFD) simulations, and experimentally using a swirl generator that generates swirling flow approximating that in a draft tube of a hydro turbine operating at a part load, featuring an unsteady spiral vortex—the vortex rope. The analytical description elucidates the effect of different installations on the circumferential velocity. Unconventional conical perforated installations targeting at increasing the dissipation were proposed and tested. The rather unsatisfactory results led to proposing fins placed unconventionally away from the wall, closer to the diffuser axis, which were subsequently shown to be able to reliably suppress the unsteady vortex rope. Their effect is documented by an analysis of CFD results including the proper orthogonal decomposition as well as experimental observations and measurements.

Keywords in English

swirling flow; vortex rope; passive flow control

Released

22.12.2022

Publisher

AIP Publishing

ISSN

1070-6631

Volume

34

Number

12

Pages from–to

1–18

Pages count

18

BIBTEX


@article{BUT182717,
  author="Pavel {Rudolf} and Ondřej {Urban} and Michaela {Kurková} and František {Pochylý},
  title="Mitigation of swirling flow with a vortex rope by passive installations—Theory, simulations, and experiments",
  year="2022",
  volume="34",
  number="12",
  month="December",
  pages="1--18",
  publisher="AIP Publishing",
  issn="1070-6631"
}