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| 1 | Profile and Secondary Flow Losses in a High-Lift LPT Blade Cascade at Different Reynolds Numbers under Steady and Unsteady Inflow Conditions显示文摘The aerodynamic flow field downstream of a Low-Pressure High-Lift(HL)turbine cascade has been experimentally investigated for different Reynolds numbers under both steady and unsteady inflows,in order to analyse the cascade performance under real engine operating conditions.The Reynolds number has been varied in the range 100000 | Satta F. Simoni D. Ubaldi M. Zunino P. Bertini F. | 2012 | Journal of Thermal Science2012，21，6： | 5 |
| 2 | Experimental Investigation of Flow Instabilities in a Laminar Separation Bubble显示文摘The present paper reports the results of a detailed experimental study aimed at investigating the dynamics of a laminar separation bubble, from the origin of separation up to the breakdown to turbulence of the large scale coherent structures generated as a consequence of the Kelvin-Helmholtz instability process. Measurements have been performed along a flat plate installed within a double contoured test section, designed to produce an adverse pressure gradient typical of Ultra-High-Lift turbine blade profiles, which induces the formation of a laminar separation bubble at low Reynolds number condition. Measurements have been carried out by means of complementary techniques: hot-wire(HW) anemometry, Laser Doppler Velocimetry(LDV) and Particle Image Velocimetry(PIV). The high accuracy 2-dimensional LDV results allow investigating reverse flow magnitude and both Reynolds normal and shear stress distributions along the separated flow region, while the high frequency response of the HW anemometer allows analyzing the amplification process of flow oscillations induced by instability mechanisms. PIV results complement the flow field analysis providing information on the generation and evolution of the large scale coherent structures shed as a consequence of the separated shear layer roll-up, through instantaneous velocity vector maps. The simultaneous analysis of the data obtained by means of the different measuring techniques allows an in depth view of the instability mechanisms involved in the transition/reattachment processes of the separated shear layer. | Simoni D. Ubaldi M. Zunino P. | 2014 | Journal of Thermal Science2014，23，3： | 4 |
| 3 | Comparative study on EUF and other methods of soil analysis for the determination of available potassium in soils from Northern Greece显示文摘 | A. D. Simonis K. Németh | 1985 | Plant and Soil1985，，1： | 1 |
| 4 | Turbine Blade Boundary Layer Separation Suppression via Synthetic Jet: an Experimental and Numerical Study显示文摘The present paper focuses on the analysis of a synthetic jet device (with a zero net massflow rate) on a separated boundary layer. Separation has been obtained on a flat plate installed within a converging-diverging test section specifically designed to attain a local velocity distribution typical of a high-lift LPT blade. Both experimental and numerical investigations have been carried out. Unsteady RANS results have been compared with experiments in terms of time-averaged velocity and turbulence intensity distributions. Two different Reynolds number cases have been investigated, namely Re = 200,000 and Re = 70,000, which characterize low-pressure turbine operating conditions during take-off/landing and cruise. A range of synthetic jet aerodynamic parameters (Strouhal number and blowing ratio) has been tested in order to analyze the features of control-separated boundary layer interaction for the aforementioned Reynolds numbers. | Bernardini C. Carnevale M. Manna M. Martelli F. Simoni D. Zunino P. | 2012 | Journal of Thermal Science2012，21，5： | 1 |
| 5 | Free-stream Turbulence Effects on the Boundary Layer of a High-lift Low-Pressure-Turbine Blade显示文摘The suction side boundary layer evolution of a high-lift low-pressure turbine cascade has been experimentally investigated at low and high free-stream turbulence intensity conditions.Measurements have been carried out in order to analyze the boundary layer transition and separation processes at a low Reynolds number,under both steady and unsteady inflows.Static pressure distributions along the blade surfaces as well as total pressure distributions in a downstream tangential plane have been measured to evaluate the overall aerodynamic efficiency of the blade for the different conditions.Particle Image Velocimetry has been adopted to analyze the time-mean and time-varying velocity fields.The flow field has been surveyed in two orthogonal planes(a blade-to-blade plane and a wall-parallel one).These measurements allow the identification of the Kelvin-Helmholtz large scale coherent structures shed as a consequence of the boundary layer laminar separation under steady inflow,as well as the investigation of the three-dimensional effects induced by the intermittent passage of low and high speed streaks.A close inspection of the time-mean velocity profiles as well as of the boundary layer integral parameters helps to characterize the suction side boundary layer state,thus justifying the influence of free-stream turbulence intensity on the blade aerodynamic losses measured under steady and unsteady inflows. | Simoni D. Ubaldi M. Zunino p. Ampellio E. | 2016 | Journal of Thermal Science2016，25，3： | 0 |
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