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contributor authorÐurović, Kristina
contributor authorDe Vincentiis, Luca
contributor authorSimoni, Daniele
contributor authorLengani, Davide
contributor authorPralits, Jan
contributor authorHenningson, Dan S.
contributor authorHanifi, Ardeshir
date accessioned2022-02-06T05:53:36Z
date available2022-02-06T05:53:36Z
date copyright5/3/2021 12:00:00 AM
date issued2021
identifier issn0889-504X
identifier otherturbo_143_8_081015.pdf
identifier urihttp://yetl.yabesh.ir/yetl1/handle/yetl/4278994
description abstractThe aerodynamic efficiency of turbomachinery blades is profoundly affected by the occurrence of laminar-turbulent transition in the boundary layer since skin friction and losses rise for the turbulent state. Depending on the free-stream turbulence level, we can identify different paths toward a turbulent state. The present study uses direct numerical simulation as the primary tool to investigate the flow behavior of the low-pressure turbine blade. In the simulations, the flow past only one blade is computed, with periodic boundary conditions in the cross-flow directions to account for the cascade. Isotropic homogeneous free-stream turbulence is prescribed at the inlet. The free-stream turbulence is prescribed as a superposition of Fourier modes with a random phase shift. Two levels of the free-stream turbulence intensity were simulated (Tu=0.19% and 5.2%), with the integral length scale being 0.167c, at the leading edge. We observed that in the case of low free-stream turbulence on the suction side, the Kelvin–Helmholz instability dominated the transition process and full-span vortices were shed from the separation bubble. Transition on the suction side proceeded more rapidly in the high-turbulence case, where streaks broke down into turbulent spots and caused bypass transition. On the pressure side, we have identified the appearance of longitudinal vortical structures, where increasing the turbulence level gives rise to more longitudinal structures. We note that these vortical structures are not produced by Görtler instability.
publisherThe American Society of Mechanical Engineers (ASME)
titleFree-Stream Turbulence-Induced Boundary-Layer Transition in Low-Pressure Turbines
typeJournal Paper
journal volume143
journal issue8
journal titleJournal of Turbomachinery
identifier doi10.1115/1.4050450
journal fristpage081015-1
journal lastpage081015-9
page9
treeJournal of Turbomachinery:;2021:;volume( 143 ):;issue: 008
contenttypeFulltext


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