Highly Resolved Hybrid RANS-LES Simulations of Different Operating Points of a Model Kaplan Turbine

S. Joßberger () and S. Riedelbauch ()
Additional contact information
S. Joßberger: Institute of Fluid Mechanics and Hydraulic Machinery
S. Riedelbauch: Institute of Fluid Mechanics and Hydraulic Machinery

A chapter in High Performance Computing in Science and Engineering '23, 2026, pp 365-378 from Springer

Abstract: Abstract Double regulated Kaplan turbines with adjustable guide vanes and runner blades offer a high degree of flexibility and good efficiency for a wide range of operating points. However, this also leads to a complex geometry and flow guidance with, for example, vortices of different size and strength. The flow in a draft tube is especially challenging to simulate mainly due to flow phenomena like swirl, separation and strong adverse pressure gradient and a strong dependency on the upstream flow conditions. The calculation of performance is often inaccurate with standard simulation approaches (i.e. RANS turbulence models, a coarse mesh and large time step size) and can lead to wrong predictions of the operating range. To reveal occurring flow phenomena and physical effects scale resolving hybrid RANS-LES simulations for three different operating points, one on-cam and two off-cam, on a block structured mesh of about 400 million hexahedral elements of a double regulated five blade model Kaplan turbine are carried out. In this paper first results of the ongoing simulations are presented. The major part of the simulation domain is running in LES mode and seems to be properly resolved. The validation of simulation results with experimental data shows good agreement in the global results, i.e. total head and power, and a good visual agreement with three-dimensional PIV measurements of the velocity. For the standard RANS simulations the results are inconsistent and the agreement with the measurement depends on the investigated operating point.

Date: 2026
References: Add references at CitEc
Citations:

There are no downloads for this item, see the EconPapers FAQ for hints about obtaining it.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:spr:sprchp:978-3-031-91312-9_25

Ordering information: This item can be ordered from
http://www.springer.com/9783031913129

DOI: 10.1007/978-3-031-91312-9_25

Access Statistics for this chapter

More chapters in Springer Books from Springer
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().