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The local structure of swirling free and impinging turbulent jets is investigated experimentally in a wide range of swirl number (from 0 to 1.00). The influence of impinging wall on the swirling jet structure is analyzed. The application of Stereo PIV technique as well as advanced post-processing procedures allowed to obtain the complete set of turbulent characteristics. The statistical moments of velocity components up to the 4 order and also all the terms of mean momentum and turbulent kinetic energy balance equations are estimated.

Two different experiments have been carried out by means of multi-plane and stereo PIV in order to analyze the structures of late transitional boundary layer flows. To achieve a better understanding of the characteristics and structures of “natural” transition scenarios, measurements in different complex initiated transitional boundary layer flows on a wing glove of a 2-D airfoil of the Tech. Univ. of Berlin have been performed. Additionally, artificially-generated turbulent spots in a laminar flat-plate boundary layer have been investigated in detail. Instantaneous velocity vector fields measured in different planes parallel to the wall and special statistical approaches applied to the vector fields of turbulent spots, yield valuable information about the structures leading to the breakdown process and governing the turbulent mixing of the boundary layer flow.

In this paper, PIV and DSPI as an alternative to stereo PIV on the measurements of 3-C velocity fields is analysed . DSPI as a velocimetry technique is described , including a discussion on the necessary requirements for going from a PIV setup into a DSPI setup and the different suitable geometries for combining PIV and DSPI. Some results from a turbulent boundary layer flow in a wind tunnel are presented including a quantitative comparison with the 3-C velocity data simultaneously measured with stereo PIV.

Flow structure behind the backward facing step in a narrow channel was studied in details. The step height was 25% of the channel width. The structure of the region just behind the step forming the back-flow region is studied in details using stereo PIV technique. Time-mean 3D structures behind the step are evaluated and shown in the paper. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

A unique, highly modular and flexible underwater system for stereoscopic particle image velocimetry (PIV) measurements has been designed, manufactured and tested. The instrument is intended for planar three-dimensional velocity measurements in large facilities such as water tow tanks and tunnels. The performance of the system is assessed in four major stereoscopic configurations. Errors under 2% for the in-plane components and 4% for the out-of-plane components are found. The system is tested in the INSEAN large circulating water channel where the measurement of the flow around a model ship oriented at a moderate yaw angle is performed and puts into evidence the main features of the flow.

Active and passive approaches to control the velocity and concentration of a high speed round particle-laden jet are investigated experimentally using a stereo PIV system. Active control of the flow field and the particles’ velocity and concentration fields, via the addition of swirl to the carrier jet, has shown to have a significant effect in altering both phases. Control is also affected by placing passive pins at the jet exit plane, which results in alteration of the velocity in planes across and normal to the pins. Furthermore, the mixing is increased and the spreading rate is modified. Depending on the number of pins used and their azimuthal location, their interaction with the carrier jet flow lead to the modification of the cross-flow shape of the jet and the direction of the flow.Copyright © 2003 by ASME

It is important to determine whether a particular cerebral aneurysm has a high risk of rupture or not so that it can be treated before subarachnoid hemorrhage occurs. Hemodynamic stresses, especially Wall Shear Stress (WSS), are considered to play an important role in formation, growth and rupture of the cerebral aneurysm. In this paper, we investigate WSS under the pulsatile inflow conditions in a realistic in vitro model of a cerebral aneurysm. The geometry of measurement model is constructed in a patient- specific manner using CT data. The stereo PIV measurement is conducted to obtain the velocity field in the cerebral aneurysm. We calculate the WSS distribution from PIV results and geometry data of lost model. The results show that overall WSS distribution in the model does not charge uniformly with time due to palsatile flow.

Measurements of velocity/vorticity of cylinder wake by using stereo-PIV method.Three-dimensional vorticity iso-surfaces were successfully reconstructed from temporal series of velocity in a cross-sectional plane assuming Taylor's hypothesis. Vortex structure having a mode A pattern was observed at Re=1000.

An experiment has been designed to help answer the questions that remained unanswered following the experiments, analysis and modelling reported in Cavalieri et al. [1]. The same Mach 0.4 turbulent jet is here considered, but this time using two independentbut-synchronised, time-resolved, stereo PIV systems. Each system can be moved independently, allowing the simultaneous measurement of three velocity components in two, axially separated, cross-flow planes. This note outlines the motivation, describes the experiment and shows some preliminary results.