Polymer induced drag reduction in turbulent pipe flow was investigated using a non-intrusive laser based diagnostic technique, namely Particle Image Velocimetry (PIV). The drag reduction was measured in a pressure-driven flow facility, in a horizontal pipe of inner diameter 25.3 mm at Reynolds numbers ranging from 35 000 to 210 000. Three highmolecular-weight polymers (polyethylene oxide 2×10 6...

Generation of “Laser Light Sheet” beams and linear laser spots characterized by uniform irradiance distribution is important in various laser techniques like Particle Image Velocimetry (PIV), Laser-Induced Fluorescence (LIF), hardening, annealing, cladding, uniform laser illumination of linear spatial light modulators. This task can be successfully solved with using refractive beam shaping opti...

background: we conducted this prospective study to evaluate the prognostic significance of uterine and ovarian artery doppler velocimetry in clomiphene citrate (cc) cycles. materials and methods: a total of 80 patients with unexplained infertility were given 100 mg/day of cc from day 3 to day 7 of their cycles in this current prospective study. on cycle day 3, before administration of cc, each ...

We demonstrate the use of a novel technique for the detection of heterodyne laser-induced thermal acoustic signals that allows the construction of a highly stable seedless laser velocimeter. A common-path configuration is combined with quadrature detection to provide flow direction, to greatly improve robustness to misalignment and vibration, and to give reliable velocity measurement at low-flo...

Laser vibration sensing provides a sensitive non-contact means of measuring vibrations of objects. These measurements are used in industrial quality control and wear monitoring as well as the analysis of the vibrational characteristics of objects. In laser vibrometry, the surface motion is monitored by heterodyne laser Doppler velocimetry, and the received heterodyne signal is sampled to produc...

A laminar boundary layer separates in a region of adverse pressure gradient, undergoes transition, and finally the turbulent boundary layer reattaches, forming a laminar separation bubble (LSB). Laminar-turbulent transition within such a LSB is investigated by means of Laser-Doppler-Anemometry (LDA), Particle Image Velocimetry (mono PIV and stereoscopic PIV (SPIV)) and direct numerical simulati...

Flowmetry. Fluid-flow measurement and visualisation ................................................................................ 1 Measuring mass flow-rate ......................................................................................................................... 2 Accumulative weighting .............................................................................................

The cross-correlation between surface temperature and subsurface velocity is presented for water undergoing evaporative convection. The surface temperature measurements were obtained via quantitative infrared imaging, and the velocity measurements were obtained using a two-component laser Doppler velocimetry (LDV) system. The water surface was covered with a surfactant monolayer, which did not ...

It has been shown that diffuse luminance flicker increases optic nerve head blood flow. The current study has been performed to quantify changes in retinal blood flow during flicker stimulation. In a group of 11 healthy volunteers, red blood cell velocity and retinal vessel diameters were assessed with bi-directional laser Doppler velocimetry and the Zeiss retinal vessel analyzer before, during...

Synthetic pyrethroids are neurotoxic insecticides with a low mammalian toxicity. Prior investigations have found these agents to be neither cutaneous irritants nor sensitisers. Clinically demonstrable inflammation, as judged by erythema, oedema, or vesiculation, has not been apparent. Nevertheless, paraesthesia does result from cutaneous exposure. In this investigation technical grade flucythri...