Acoustic sensing of hydrodynamic vortex flow

We report the results of experiments of sound scattering by a vortex flow formed behind a grid of vertical cylinders placed in an air flow. The experiments were carried out in a low turbulence wind tunnel at a low Reynolds number. The vortex flow was formed behind a grid of 3-10 of hollow cylinders with the d=2 mm and length 30 mm. During the experiments we could change the gap between the cylinders g=L/d (where L is a distance between the cylinders surfaces) from 3 to 5. The experiments showed that at a certain value of g vortex flows behind different cylinders could synchronize and this effect could be easily detected by means of distant acoustic sensing. This result was also confirmed by means of direct measurements of velocity field of the vortex flow

Remote acoustic diagnostics of defects arising in a Kármán vortex street behind a heated cylinder

International audienceAcoustic diagnostics allows detection of defects in a periodic Kármán vortex street behind a heated cylinder by a fine structure of scattering spectra. We found that over a definite range of heating power, defects appear in the street against the background of a periodic structure. It was shown that by acoustic diagnostics one can obtain data on a spatial period of a Kármán street and its drift velocity over a wider temperature range than by measurements using two sensors placed in the wake of a cylinder. This occurs due to the space averaging during acoustic measurements: the parameters of scattered sound are determined by the length of the Kármán street, which includes a large number of spatial periods

BioPhys4_08SoustovLO

Abstract -Here we compile and analyze the data on photoaggregation of a model protein carboanhydrase and the main eye lens proteins α -, β -, γ -crystallins under the action of pulsed UV irradiation from a Xe-Cl laser (308 nm) with broad variation of pulse energy density and repetition rate. The aggregation efficacy proves to be a nonlinear function of these parameters and protein concentration. A theoretical model is proposed that qualitatively explains the experimental data. It is shown that N-arm-truncated β A3-crystallin is more prone to UV-induced aggregation than the full-sized protein; such defects caused by mutation or aging may aggravate the development of lenticular opacity. Analyzed is the effect of some low-molecular compounds on the aggregation of β -crystallin and its mixture with α -crystallin. A combination of short peptides prepared on this basis markedly impedes crystallin aggregation and retards the development of UV-induced cataract in rats