A scheme for molecular tagging velocimetry is presented that can be used in air flows without any kind of seeding. The method is based on the local and instantaneous creation of nitric oxide (NO) molecules from N(2) and O(2) in the waist region of a focused ArF excimer laser beam. This NO distribution is advected by the flow and can be visualized any time later by laser-induced fluorescence in ...

We describe a method for measuring three dimensional (3D) velocity fields of a fluid at high speed, by combining a correlation-based approach with in-line holography. While this method utilizes tracer particles contained within the flow, our method does not require the holographic reconstruction of 3D images. The direct flow reconstruction approach developed here allows for measurements at seed...

Background: Optical distortions can significantly deteriorate the measurement accuracy in particle image velocimetry systems. Such distortions can occur at fluctuating phase boundaries during flow measurement and result from the accompanied refractive index changes. The usage of a wavefront sensor can be hindered by disturbing light reflexes or scattering. Methods: A combination of sharpness me...

Spatially resolved Pulsed Field Gradient (PFG) velocimetry techniques can provide precious information concerning flow through opaque systems, including rocks. This velocimetry data is used to enhance flow models in a wide range of systems, from oil behaviour in reservoir rocks to contaminant transport in aquifers. Phase-shift velocimetry is the fastest way to produce velocity maps but critical...

This paper examines various techniques that have been developed to measure flow fields in microfluidic devices with 10 – 10 micron-scale spatial resolution. These techniques include Scalar Image Velocimetry (SIV), Laser Doppler Velocimetry (LDV), and Particle Image Velocimetry (PIV). Advantages and disadvantages of these techniques are presented. PIV results are presented for a liquid flow thro...

The contribution of holographic techniques to particle velocity measurements is discussed. Two-dimensional holographic particle image velocimetry and three-dimensional holographic velocimetry are described and compared. Their advantages and limits are discussed and the latest progress in this domain is presented, together with perspectives for the near future.

velocity vector fields by ultrasound particle imaging velocimetry: in vitro comparison with optical flow velocimetry. blood flow patterns in normal subjects: a quantitative analysis by three-dimensional magnetic resonance velocity mapping. A new echo-cardiographic method for identifying vortex flow in the left ventricle: numerical validation.dimensional intraventricular flow mapping by digital ...

the aim of the present study was to investigate the influence of nozzle configurations on spray drift and explain the influences using several atomization characteristics (length of spray sheet, spray angle, velocity distribution of flow field, fluctuation of velocity, and droplet size). nozzles manufactured by one company (lechler gmbh, germany) were tested by spraying local tap water in a win...

Background. The transient effects of epidural bupivacaine 0.25–0.5% on the Doppler velocimetry of umbilical and uterine arteries had been reported, but the effects of continuous lower dose epidural bupivacaine (0.05–0.1%) infusion for labour analgesia have never been reported. In this study, we evaluated the effects of continuous epidural bupivacaine 0.075% on the Doppler velocimetry of uterine...