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| 1 | Unsteady Inflow Effects on the Wake Shed from a High-Lift LPT Blade Subjected to Boundary Layer Laminar Separation显示文摘An experimental investigation on the near and far wake of a cascade of high-lift low-pressure turbine blades subjected to boundary layer separation over the suction side surface has been carried out, under steady and unsteady inflows. Two Reynolds number conditions, representative of take-off/landing and cruise operating conditions of the real engine, have been tested. The effect of upstream wake-boundary layer interaction on the wake shed from the profile has been investigated in a three-blade large-scale linear turbine cascade. The comparison between the wakes shed under steady and unsteady inflows has been performed through the analysis of mean velocity and Reynolds stress components measured at midspan of the central blade by means of a two-component crossed miniature hot-wire probe. The wake development has been analyzed in the region between 2% and 100% of the blade chord from the central blade trailing edge, aligned with the blade exit direction. Wake integral parameters, half-width and maximum velocity defects have been evaluated from the mean velocity distributions to quantify the modifications induced on the vane wake by the upstream wake. Moreover the thicknesses of the two wake shear layers have been considered separately in order to identify the effects of Reynolds number and incoming flow on the wake shape. The self-preserving state of the wake has been looked at, taking into account the different thicknesses of the two shear layers. The evaluation of the power density spectra of the velocity fluctuations allowed the study of the wake unsteady behavior, and the detection of the effects induced by the different operating conditions on the trailing edge vortex shedding. | Francesca Satta Marina Ubaldi Pietro Zunino | 2012 | Journal of Thermal Science2012，21，2： | 1 |
| 2 | An Experimental Study of Unsteady Characteristics of the turbulent Near Weak of a Turbine Blade 显示文摘 | Marina Ubaldi Pietro Zunino | 2000 | Experimental Thermal and Fluid Science2000，23，： | 1 |
| 3 | An experimental study of the unsteady characteristics of the turbulent near wake of a turbine blade显示文摘 | Marina Ubaldi Pietro Zunino | 2000 | Experimental Thermal and Fluid Science2000，23，： | 1 |
| 4 | An Experimental Study of the Unsteady Characteristics of the Turbulent Near Wake of a Turbine Blade 显示文摘 | Marina Ubaldi Pietro Zunino | 2000 | Experimental Thermal and Fluid Science2000，23，： | 1 |
| 5 | Large Eddy Simulation of the By-pass Transition Process under Different Inlet Turbulence Conditions显示文摘The transition process of the boundary layer developing over a flat plate with elevated inlet Free Stream Turbulence Intensity(FSTI)has been studied by means of Large Eddy Simulation(LES).To this purpose,four cases with different inflow disturbances have been tested varying the magnitude and the length scale of turbulence.LES has been performed by using the finite-volume ANSYS Fluent code.The computational domain,which was constituted by a rectangular domain with a zero thickness plate,was based on an ERCOFTAC test case in order to provide a validation with a well-known set of data by comparing the boundary layer integral parameters and mean and fluctuating streamwise velocity profiles.The four cases were discussed within the paper by looking at classical statistical properties as well as advanced post-processing tools.It was shown that the decrease in the free stream turbulence level postpones the transition location,whereas the variation of the integral length scale has a very low influence on the distribution of the time-mean flow properties.Proper Orthogonal Decomposition(POD)has been applied to the instantaneous LES flow fields in order to provide a statistical representation of the structures responsible for transition and their response to free-stream turbulence intensity and length scale.The presence of vortical filaments parallel to the wall,typically referred as boundary layer streaks,is clearly identified;their characteristic dimensions and how they change as a function of FSTI properties were analyzed within the paper. | BARSI Dario COSTA Carlo LENGANI Davide SIMONI Daniele UBALDI Marina | 2021 | Journal of Thermal Science2021，30，6： | 0 |
| 6 | An Experimental Investigation of the Dissipation Mechanisms in the Suction Side Boundary Layer of a Turbine Blade显示文摘现在的工作是作者在针对在汽轮机片调查界面层转变现象的最近的年里执行的一项广泛的试验性的活动的部分。串联的大规模和先进 LDV 乐器学和精确探查穿越机制的使用导致了空间分辨率的高度和大小的高精确性。在涡轮机械片决定侧面损失的主要驱散机制是界面层操作了由的在内的吝啬的运动的变丑的工作粘滞、狂暴砍压力。在现在的报纸,粘滞的本地人和狂暴的变丑工作直接从界面层平均数速度和雷纳兹的详细大小被评估了砍应力。结果显示出分布和相对重要性粘滞、狂暴对损失生产的贡献,在有界面层的关系,沿着汽轮机发生的状态介绍。 | Francesca Satta Daniele Simoni Marina Ubaldi Pietro Zunino | 2008 | Journal of Thermal Science2008，17，4： | 0 |
| 7 | Experimental Analysis of the Aerodynamic Performance of an Innovative Low Pressure Turbine Rotor显示文摘In the present work the aerodynamic performances of an innovative rotor blade row have been experimentally investigated. Measurements have been carried out in a large scale low speed single stage cold flow facility at a Reynolds number typical of aeroengine cruise, under nominal and off-design conditions. The time-mean blade aerodynamic loadings have been measured at three radial positions along the blade height through a pressure transducer installed inside the hollow shaft, by delivering the signal to the stationary frame with a slip ring. The time mean aerodynamic flow fields upstream and downstream of the rotor have been measured by means of a five-hole probe to investigate the losses associated with the rotor. The investigations in the single stage research turbine allow the reproduction of both wake-boundary layer interaction as well as vortex-vortex interaction. The detail of the present results clearly highlights the strong dissipative effects induced by the blade tip vortex and by the momentum defect as well as the turbulence production, which is generated during the migration of the stator wake in the rotor passage. Phase-locked hot-wire investigations have been also performed to analyze the time-varying flow during the wake passing period. In particular the interaction between stator and rotor structures has been investigated also under off-design conditions to further explain the mechanisms contributing to the loss generation for the different conditions. | Infantino Daniele Satta Francesca Simoni Daniele Ubaldi Marina Zunino Pietro Bertini Francesco | 2016 | Journal of Thermal Science2016，25，1： | 0 |
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