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...

An rf-modulated pulse train from a passively Q-switched Nd:YAG laser has been generated using an extra-cavity acousto-optic modulator. The rf modulation reproduces the spectral quality of the local oscillator. It leads to a high pulse-to-pulse phase coherence, i.e., phase memory, over thousands of pulses. The potentialities of this transmitter for lidar-radar are demonstrated by performing Dopp...

PURPOSE Alprostadil, a prostaglandin (PG)E(1) analogue and pentoxifylline, an alkylxanthine derivate, have been shown to exert vasodilatory effects in several vascular beds. The purpose of the present study was to investigate the effect of PGE(1) and pentoxifylline on the ocular circulation. METHODS A placebo-controlled, double-masked, three-way, crossover study was performed in 15 healthy ma...

Self-mixing laser Doppler velocimetry using a dual-polarization Yb:Er-doped phosphate glass laser is investigated. The two orthogonally polarized eigenstates emitted simultaneously by the laser oscillator are employed to perform a heterodyne detection, allowing a complete characterization of the lateral sidebands generated via the optical feedback around the beating peak. Two different experime...

We demonstrate, to our knowledge, the first on-chip heterodyne interferometer fabricated on a 300-mm CMOS compatible process that exhibits root-mean-square (RMS) position noise on the order of 2 nm. Measuring 1 mm by 6 mm, the interferometer is also, to our knowledge, the smallest heterodyne interferometer demonstrated to date and will surely impact numerous interferometric and metrology applic...

We present an experiment designed to study magnetohydrodynamic effects in free surface channel flow. The wide aspect ratio channel (the width to height ratio is about 15) is completely enclosed in an inert atmosphere to prevent oxidization of the liquid metal. A custom-designed pump reduces entrainment of oxygen, which was found to be a problem with standard centrifugal and gear pumps. Laser Do...

Progress toward extraction of the elusive pressure-densitycorrelation in variable density reacting flows is reported uponin this paper, using a premixed methane—air flame in open sur-roundings as the test medium. The relationship between den-sity and other scalars is shown. Molecular Rayleigh scattering,laser Doppler velocimetry, and dynamic Pitot barometry are theexperi...