Smykové vrstvy vystavené nepříznivému tlakovému gradientu mají sklon k destabilizaci a vzniku koherentních vírových struktur. Projekt se zaměřuje na popis jejich časově-prostorového chování za pomoci pokročilých experimentálních (stereo time-resolved PIV) a výpočtových metod (LES). Rozsah prací se omezuje na dva kanonické případy: prizmatické těleso obtékané příčně a kuželový difuzor s obvodovou složkou rychlosti na vstupu. Na základě detailního zachycení nestacionárních proudových polí bude provedena extrakce koherentních vírových struktur a sestaven redukovaný dynamický model. Výsledkem bude hlubší pochopení vzniku nestabilit, jejich chování a vlivu na silovou interakci proudu s obtékaným povrchem jako nutný předstupeň pro cílené řízení proudění

Description in English
Shear layers imposed to adverse pressure gradient are susceptible to instability and onset of coherent vortical structures. Project is focused on description of their spatio-temporal behavior using advanced experimental (stereo time-resolved PIV) and computational methods (large eddy simulation). Work extent is limited to two canonical cases: prismatic body in cross-flow and conical diffuser with inlet circumferential velocity component. Extraction of the coherent vortical structures and reduced order model construction will be performed based on the detail capturing of the unsteady velocity fields. The result will be deeper understanding of the instability onset and behavior and its effect on fluid-structure force interaction as necessary precursor of the effective active flow control strategies.

Keywords
smyková oblast; nestabilita; prostorovost; nepříznivý gradient tlaku; koherentní vírové struktury

Key words in English
shear layer;instability;3D;adverse pressure gradient;coherent vortical struct

GA17-01088S

Czech

Uruba Václav, prof. Ing., CSc. - principal person responsible
Rudolf Pavel, doc. Ing., Ph.D. - fellow researcher

Energy Institute
- responsible department (26.5.2017 - not assigned)
Victor Kaplan Dept. of Fluid Engineering
- co-beneficiary (1.1.2017 - 31.12.2019)
Institute of Thermomechanics Academy of Sciences of the Czech Republic
- beneficiary (1.1.2017 - 31.12.2019)

URBAN, O.; KURKOVÁ, M.; RUDOLF, P. Application of Computer Graphics Flow Visualization Methods in Vortex Rope Investigations. ENERGIES, 2021, vol. 14, no. 3, p. 1-21. ISSN: 1996-1073.
Detail

ŠTEFAN, D., RUDOLF, P., HUDEC, M., URUBA, V., PROCHÁZKA, P. URBAN, O. Experimental investigation of vortex ring formation as a consequence of spiral vortex re-connection. In IOP Conference Series: Earth and Environmental Science. IOP Conference Series: Earth and Environmental Science. 2019. p. 1-6. ISSN: 1755-1315.
Detail

URBAN, O.; RUDOLF, P. POD analysis of a vortex rope with transient boundary conditions. In IOP Conference Series: Earth and Environmental Science. IOP Conference Series: Earth and Environmental Science. 2019. p. 1-6. ISSN: 1755-1315.
Detail

POCHYLÝ, F.; URBAN, O.; FIALOVÁ, S. Reduction of the mathematical model of liquid flow within an instability. In IOP Conference Series: Earth and Environmental Science. IOP Conference Series: Earth and Environmental Science. 2019. p. 1-10. ISSN: 1755-1315.
Detail

RUDOLF, P.; URBAN, O.; ŠTEFAN, D. Construction of a reduced-order dynamic model for prospective swirling flow control in hydraulic turbine draft tube. In IOP Conference Series: Earth and Environmental Science. IOP Conference Series: Earth and Environmental Science. 2019. p. 1-10. ISSN: 1755-1315.
Detail

RUDOLF, P.; URBAN, O.; ŠTEFAN, D.; POCHYLÝ, F. Flow control in hydraulic machinery. In 20. Internationales Seminar Wasserkraftanlagen. Vienna: 2018. p. 651-660. ISBN: 978-3-9504338-1-4.
Detail

RUDOLF, P.; LITERA, J.; IBARRA BOLANOS, G.; ŠTEFAN, D. Manipulation of the swirling flow instability in hydraulic turbine diffuser by different methods of water injection. In EPJ Web of Conferences. EPJ Web of Conferences. EDP Sciences, 2018. p. 1-6. ISSN: 2100-014X.
Detail

RUDOLF, P.; POCHYLÝ, F.; URBAN, O.; KLAS, R.; HIMR, D. Racionální využití CFD v praxi. Praha: TechSim s.r.o., 2017. s. 1-25.
Detail

ŠTEFAN, D.; RUDOLF, P.; MUNTEAN, S.; SUSAN-RESIGA, R.;. Proper Orthogonal Decomposition of Self-Induced Instabilities in Decelerated Swirling Flows and Their Mitigation Through Axial Water Injection. JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME, 2017, vol. 139, no. 8, p. 1-25. ISSN: 0098-2202.
Detail

Responsibility: Uruba Václav, prof. Ing., CSc.