Laser driven shockwaves from nanosecond pulsed lasers were evaluated for pressure magnitude and duration using photon Doppler velocimetry (PDV). Specific investigations performed on Ti-6Al-4V alloys 7085-T7651 aluminum with laser full-width half-max pulse lengths ranging 6 to 20 ns intensities of 2–10 GW/cm2. The rear surface velocity data obtained a heterodyne PDV system an automated signal pr...

A preliminary comparative measurement between particle imaging velocimetry (PIV) and laser speckle contrast analysis (LASCA) to study pulsatile flow using ventricular assist device in a patient-specific carotid artery phantom is reported. These full-field optical techniques have both been used to study flow and extract complementary parameters. We use the high spatial resolution of PIV to gener...

The principal advantage of optical sensors for medical applications is their intrinsic safety since there is no electrical contact between the patient and the equipment. (An added bonus is that they are also less suspect to electromagnetic interference). This has given rise to a variety of optical techniques to monitor physiological parameters: for example, the technique of Laser Doppler veloci...

This study is an attempt to determine if there is any speed sensitive phenomenon in flapper valve operation. Valve motion is measured at various speeds in a reciprocating residential refrigerator/freezer compressor. Laser Doppler Velocimetry is used to measure the velocity of a point on the flapper at the center of the port for the suction valve. This velocity data is numerically integrated to ...

Colloidal particles in a liquid medium are transported with constant velocity, and dynamic light scattering experiments are performed on the samples by self-mixing laser Doppler velocimetry. The power spectrum of the modulated wave induced by the motion of the colloidal particles cannot be described by the well-known formula for flowing Brownian motion systems, i.e., a combination of Doppler sh...

A method for the simultaneous measurement of velocity and passive scalar concentration fields by means of particle image velocimetry (PIV) and planar laser induced florescence (PLIF) techniques is described here. An application of the combined PIV-PLIF system is demonstrated by performing simultaneous velocity and concentration measurements in the near field of a turbulent jet mixing flow. The ...

When a fluid is heated by the absorption of a continuous laser wave, the fluid density decreases in the heated area. This induces a pressure gradient that generates internal motion of the fluid. Due to mass conservation, convection eddies emerge in the sample. To investigate these laser-driven bulk flows at the microscopic scale, we built a setup to perform temperature measurements with a fluor...

We present laser-induced fluorescence (LIF) measurements of neutral xenon (6s [3/2]2) in the near-field plume of a 6-kW Hall thruster. The 823.163 nm (air) beam from a TUI Optics TA-100/830 tapered-amplifier diode laser is focused along an axial beamline onto a submillimeter interrogation volume, from which we collect resonant LIF. Polarization control via a rotating half-wave plate keeps the i...