LEGI - UMR 5519

Financial support : ADEME/Alstom Hydro France

The reliable numerical simulation of hydraulic turbines performance requires : i) to includeinto the conventional RANS computations the effect of the uncertainties existing in practiceon the inflow conditions; ii) to rely on a LES (Large Eddy Simulation) strategy to improve thedescription of turbulence effects when discrepancies between RANS computations and experimentskeep arising even though uncertainties are taken into account. The present workapplies a non-intrusive Uncertainty Quantification strategy (NISP for Non-Intrusive SpectralProjection) to two configurations of practical interest : a Francis turbine distributor, with uncertaininlet flow rate and angle, and a draft-tube of a bulb-type turbine with uncertain inflowconditions (velocity distributions, in particular close to the wall boundaries, and turbulentquantities). The NISP method is not only used to compute the mean value and variance ofquantities of interest, it is also applied to perform an analysis of the variance and identify inthis way the most influential uncertainties. The RANS simulations, verified through a gridconvergence approach, are such the discrepancies between computation and experimentcannot be explained by taking into account the inflow uncertainties for most of the configurationsunder study. Therefore, LES simulations are also performed and these simulations areverified using an original methodology for assessing the quality of the computational grids(since the grid-convergence concept is not relevant for LES). For most of the flows understudy, combining a SGE strategy with a UQ approach yields reliable numerical results. Takinginto account inflow uncertainties also allows to propose a robust optimization strategy forthe Francis turbine distributor under study.

Publications

Peer-reviewed Publications

2013

Brugière, O., Balarac, G., Corre, C. E., Métais, O., Flores, E., & Leroy, P. (2013). Numerical optimization of a Francis turbine’s guide vane axis location including inflow uncertainties. La Houille Blanche – Revue internationale de l’eau, .

  

2011

Duprat, C., Balarac, G., Métais, O., Congedo, P. M., & Brugière, O. (2011). A wall-layer model for large-eddy simulations of turbulent flows with/out pressure gradient. Physics of Fluids, 23, 015101.

  

Conference Proceedings

2012

Brugière, O., Balarac, G., Corre, C. E., Métais, O., Flores, E., & Leroy, P. (2012). Numerical optimization of a Francis turbine’s guide vane axis location including inflow uncertainties. In SimHydro 2012 : Nouvelles frontières de la simulation (pp. 1–8). Sophia-Antipolis, France.

  

Brugière, O., Balarac, G., Corre, C. E., Métais, O., Flores, E., & Leroy, P. (2012). Numerical prediction of a draft tube flow taking into account uncertain inlet conditions. In 26th IAHR Symposium on Hydraulic Machinery and Systems (pp. 1–8). Pékin, China.

  

2010

Balarac, G., Kosovichev, A., Brugière, O., Wray, A., & Mansour, N. (2010). Modeling of the subgrid-scale term of the filtered magnetic field transport equation. In Proceedings of the Summer Program 2010. Stanford, United States: Stanford University.

  

Congedo, P. M., Brugière, O., Balarac, G., Métais, O., & Duprat, C. (2010). A wall model for LES of turbulent flows with/out pressure gradient. In ERCOFTAC Workshop Direct and Large Eddy Simulation 8. Eindhoven, Netherlands.

  

Ph.D. Theses

2015

Brugière, O. (2015). Fiabilité et évaluation des incertitudes pour la simulation numérique de la turbulence : application aux machines hydrauliques. Ph.D. thesis, Université Grenoble Alpes, .