Laser-anemointerferometer for simultaneous measurements of velocity and density

Study of unsteady convection through simultaneous velocity and interferometric measurements

“…In contrast with this technique, a full map of the temperature perturbations can be obtained through interferometric measurements [4], and, then, usefully combined with velocity measurements. An alternative differential interferometric method, using Wollaston prisms, has been proposed [5, 6] and widely used in the case of Rayleigh-Benard convection [7,8]. In this letter, we present a much simpler optical system which provides differential interferogrammes ; moreover, the simultaneous use of this interferometric technique with laser Doppler velocimetry on the same sample, is a very powerful method; this point is illustrated in the study of unsteady convective motion, from which new information on the mechanism of the oscillatory regime in high Prandtl number fluids is obtained.…”

Non-isothermal flow diagnostics using microencapsulated cholesteric particles

“…The uncertainty of our measurements turned out to be less than 5%. Furthermore, the experi- --theortical prediction of [7 ] o LDV measurements A PIV measurements exhibits two symmetrically arranged vortices within the illuminated plane which are driven by buoyancy and thermocapillarity, respectively. The relatively large particle displacements near the bubble contours distinctly demonstrate that the bubble surface is the principle driver of the flow.…”

“…In order to test our method regarding the velocity measurements we compared our PIV-data with two-dimensional nu/nerical predictions by Oertel [7]. Figure 4 displays scaled vertical velocities uv of the horizontal midplane of the Brnard configuration.…”