the proper and quantitative recognition of the scale of turbulence in regard to issues such as sediment transport is of major importance. different experimental techniques can be used to determining the scale of turbulence, but the accuracy of these techniques is open to question. in this paper, after a review of the taylor method, the restrictions and advantages of velocity measurement techniq...

This paper describes features in the structure of a laminar vortex ring ejected vertically from an elevated pipe into a uniform horizontal cross flow. Measurements are obtained by particleimage velocimetry (PIV) and flow-visualisation images are obtained by planar-laser-induced fluorescence (PLIF). Cross flow produces a shear layer over the open end of the elevated pipe. As a vortex ring is eje...

Optical-flow (OF) velocimetry is based on extracting velocity information from two-dimensional scalar images and represents an unseeded alternative to particle-image velocimetry in turbulent flows. The performance of the technique is examined by direct comparison with simultaneous particle-image velocimetry in both an isothermal turbulent flow and a turbulent flame by use of acetone-OH laser-in...

We propose a point measurement technique for simultaneous gas temperature and velocity measurement based on thermographic phosphor particles dispersed in the fluid. The flow velocity is determined from the frequency of light scattered by BaMgAl10O17:Eu2+ phosphor particles traversing the fringes like in conventional laser Doppler velocimetry. Flow temperatures are derived using a two-color rati...

A new laser velocimetry technique, Doppler global velocimetry, is described. This technique is capable of simultaneously measuring in real time the three components of velocity of an entire particle field i l luminated by a laser l ight sheet . A prototype one-component velocimeter is described along with the signal processing electronics. The system was tested by measuring the velocity field f...

BACKGROUND The zebrafish Danio rerio is an important model system for drug discovery and to study cardiovascular development. Using a laser-scanning confocal microscope, we have developed a non-invasive method of measuring cardiac performance in zebrafish embryos and larvae that obtains cardiovascular parameters similar to those obtained using Doppler echocardiography in mammals. A laser scan l...