Acoustic resonances in Francis turbines often define undesirable limitations to their operating ranges at high load. The knowledge of the mechanisms governing the onset and the sustenance of these instabilities in the swirling flow leaving the runner is essential for the development of a reliable hydroacoustic model for the prediction of system stability. The present work seeks to study experim...

Here we describe the application of a multiple camera planar particle image velocimetry (PIV) measurement to achieve a large field of view (FOV) in a high Reynolds number turbulent boundary layer. Measurements are performed over a FOV of 0.8m × 0.5m (2.25δ × 1.4δ, where δ denotes the boundary layer thickness) in the streamwise and wall-normal directions respectively in a turbulent boundary laye...

Turbulence data is analysed with time series analysis. The data was measured in a shallow flow facility with Laser Doppler Anemometry (LDA). A regularly sampled signal is extracted from the irregular LDA-data using Nearest Neighbor Resampling (NNR). NNR is used because it is robust and provides an unbiased estimate of the variance. From the resampled signal a time series model is estimated. The...

Computational methods are emerging as powerful tools for quantifying blood flow in arteries for disease research, medical device design and treatment planning. The motivation for quantifying hemodynamic conditions in the human vascular system is presented. A computational method for modeling blood flow, based on the theory of stabilized finite element methods, is detailed and shown to yield exc...

Nowadays using of new energies in the form of dispersed resources in the worlds is wide spreading. In this article we will design a dispersed production source in the form of a solar/wind hybrid power plant in order to supply the energy of a residential unit according to a sample load pattern. The aim of aforementioned design is to reduce its costs in a period of 20 years. In order to optimi...

During its near-ground hovering phase a Short Take-Off and Vertical Landing (STOVL) aircraft creates a complex three-dimensional flow field between jet streams, the airframe surface and the ground. A proper understanding and numerical prediction of this flow is important in the design of such aircraft. In this paper an experimental facility, used to gather validation data suitable for testing C...

(2006) Laser-optical investigation of stator-rotor interaction in a transonic turbine, 1 ABSTRACT This paper presents research in a highly-loaded cold-flow transonic turbine under continuous and engine like conditions. Special focus was placed on blade row interaction at app. 10600 rpm. While the first step was the investigation of a single stage machine (stator-rotor), the second step extended...

Measurements of mean velocity, turbulence intensity, and turbulent shear stresses are presented for the mixing region of a film cooling situation in which the coolant is laterally injected. Measurements are performed using triple-wire anemometry so that all three mean velocity components are documented. Such measurements also give Reynolds stress terms in the flow field. Flow with one row of fi...

In this study, the effect of limited spatial resolution of hot wire anemometry (HWA) is investigated through analysis of the two dimensional energy spectra from direct numerical simulation (DNS) of turbulent channel flow at Reτ ≈ 934. Various spanwise filter lengths are applied to the streamwise velocity component in order to mimic the spatial resolution of the HWA experiments. The overall effe...

Bubble nuclei populations in the wake of a circular cylinder under cavitating and noncavitating conditions were measured using a Phase Doppler Anemometry (PDA) system. In addition, the mean velocity defect and the turbulent fluctuations were monitored in order to try to understand the nuclei population dynamics within the flow. At the Reynolds numbers of these experiments (20000 + 33000) the la...