My objectives were to (a) measure the size-dependent particle concentration and settling velocities with the use of newly developed instruments funded through this program. These instruments, LISST100 and LISST-ST employ the principles of multi-angle light scattering and a mathematical inversion of these measurements for estimating the particle concentration in 32 log-spaced (equi-phi) interval...

In this article we present a novel optical sensor allowing simultaneous measurements of axial position and tangential velocity of moving solid state objects. An extended laser Doppler velocimeter setup is used where two interference fringe systems are superposed slightly tilted. The axial position of moving solid state surfaces is determined via a phase evaluation. The phase laser Doppler dista...

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...

An experimental study of Taylor’s hypothesis in a quasi-two-dimensional turbulent soap film is presented. A two-probe laser Doppler velocimeter enables a nonintrusive simultaneous measurement of the velocity at spatially separated points. Using the cross correlation between a pair of points displaced in both space and time, the velocity coherence is measured to be better than 90% for scales les...

A n experimental investigation of a solid–liquid dispersion pipe flow was conducted using a pulsed ultrasonic Doppler velocimeter. The solid phase was composed of buoyant particles dispersed in water. This particular two-phase flow was used to mimic the behaviour of ice–water flow. Four diagnostics were used to study the complex nature of the two-phase flow mixtures: mean velocity profiles, spa...

Copyright© 2001 by Gharib, Modarress, Fourguette, and Wilson. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Abstract This manuscript describes two MEMS based optical sensors for wall shear stress and velocity measurements in flow fields. Experimental results obtained with the wall shear stress sensor, the MicroS3, are compared with boundary layer ve...

An adaptive computer-based spatial-filtering velocimeter to measure the surface velocity of a natural debris flow with high accuracy is described that can adjust the filter parameters, specifically, the slit width of the filter, based on the surface-pattern characteristics of the flow. A computer simulation confirms the effectiveness of this technique. The surface velocity of a natural debris f...

this paper carries out the experimental research and analysis on the vortex-excited vibration suppression effect of the spiral stripe strake via the laser particle velocimeter (PIV) under vortex speed U=0.6 m/s and attack angle α=300 and discusses the VIV suppression mechanism of the spiral stripe strake by using the numerical simulation of the computational fluid dynamics (CFD) in order to obj...

An experimental study of Taylor’s hypothesis in a quasi-two-dimensional turbulent soap film is presented. A two probe laser Doppler velocimeter enables a non-intrusive simultaneous measurement of the velocity at spatially separated points. The breakdown of Taylor’s hypothesis is quantified using the cross correlation between two points displaced in both space and time; correlation is better tha...