New technologies for fluid dynamics experiments and optical diagnostics

Abstract

Modern technologies offer new opportunities for experimentalists in a wide variety of research areas including hydrodynamics. A significant improvement in precision, dynamic range, reproducibility, motion control accuracy, data acquisition rate and information capacity of the experimental datasets over the current state-of-the-art are possible using new approaches and techniques, which may bring the quality of experiments to a new level of standards. Application of these new technologies in experimental diagnostics can help bridge the current quality gap between the observations and the large-scale computational fluid dynamics simulations allowing direct and unambiguous comparison of the data and the modeling results, which is crucial for the code validation. One of the new technologies which is described in this paper is ultra-high performance digital holographic data storage. The state-of-the-art motion control, electronics and optical imaging allow for realization of turbulent flows with very high Reynolds number (>107) in a relatively small laboratory-scale form-factor and quantification of their properties with extremely high spatio-temporal resolutions and bandwidth. Digital holographic technology can provide complete three-dimensional mapping of the flow velocity and density fields at high data rates (over 1000 fps) over large spatial area (∼50 cm) with high spatial (1–10 μm) and temporal (better than a few nanoseconds) resolutions and, therefore, can provide extremely accurate quantitative description of the fluid flows, including those of multiphase and unsteady conditions. These unique experimental and metrological capabilities enable the studies of spatial and temporal properties of the transport of momentum, angular momentum and energy, and the identification of scaling, invariants and statistical properties of the complex multiphase and unsteady turbulent flows. The technology can be applied for investigations of a large variety of hydrodynamic problems including the fundamental properties of non-Kolmogorov turbulence, flow–particle interactions, accelerating and rotating flows, boundary layers, Rayleigh–Taylor instability and turbulent mixing, magneto-hydrodynamics and laboratory astrophysics.