000033003 001__ 33003
000033003 005__ 20190509132001.0
000033003 0247_ $$2doi$$a10.5075/epfl-thesis-2527
000033003 02471 $$2nebis$$a4323803
000033003 037__ $$aTHESIS
000033003 041__ $$aeng
000033003 088__ $$a2527
000033003 245__ $$aNumerical simulation and flow analysis of an elbow diffuser
000033003 269__ $$a2002
000033003 260__ $$bEPFL$$c2002$$aLausanne
000033003 300__ $$a201
000033003 336__ $$aTheses
000033003 502__ $$aMichel Deville, Jacques Giovanola, Charles Hirsch, Helmut Keck, Jean-Louis Kueny, Albert Ruprecht
000033003 520__ $$aNumerical simulation of the unsteady turbulent flow in a three-dimensional elbow diffuser is performed. The investigation is carried out with a commercial finite volume solver implementing the Reynolds averaged Navier-Stokes equations. Against the background of current research in DNS and LES, the modeling of most practically relevant turbulent flows continues to be based on this system of equations. For this reason it is important to evaluate the limitations of the Reynolds averaging approach with the associated turbulence modeling, in particular for the prediction of time-dependent flows. Verification and validation are presented; detailed measurements are compared with computations. While a great deal of research has focused on draft tube design, relatively little is known about the complex flow features present. The flow is analyzed over a wide range of operating conditions including part load. Topological changes in the flow patterns with the global characteristics of the diffuser are presented. Visualization provides extra insight into the complex flow. Forced and self-sustained time-dependent flow phenomena are captured. Falling into these categories are flow field fluctuations introduced by the runner, self-sustained vortex shedding phenomena, and the typical rotating helical vortex observed at part load. Additionally, the linear stability of measured inlet profiles is investigated, providing a fuller understanding of the basic instability mechanism.
000033003 700__ $$0241844$$g114731$$aMauri, Sebastiano
000033003 720_2 $$aAvellan, François$$edir.$$g104417$$0241012
000033003 8564_ $$uhttps://infoscience.epfl.ch/record/33003/files/EPFL_TH2527.pdf$$zTexte intégral / Full text$$s22359377$$yTexte intégral / Full text
000033003 909C0 $$xU10309$$0252135$$pLMH
000033003 909CO $$pSTI$$pDOI$$ooai:infoscience.tind.io:33003$$qDOI2$$qGLOBAL_SET$$pthesis
000033003 918__ $$bSTI-SGM$$cISE$$aSTI
000033003 919__ $$aLMH
000033003 920__ $$b2002$$a2002-2-22
000033003 970__ $$a2527/THESES
000033003 973__ $$sPUBLISHED$$aEPFL
000033003 980__ $$aTHESIS