Abstract:

This dataset contains the summary of turbulence measurements using polarimetric lidar in the water channel facility at the University of Southern California. The measurements were collected in a 17 m long flume tank with a heating element and turbulence generating grid. Depolarization rate and light attenuation coefficient for varying turbulent flow strength, particle concentration, and composition were determined using a polarimetric lidar system. The dataset includes a table with the summary of all the experiment runs (14) over 5 consecutive days. Each run was around 2.5 hours long. The first 30 minutes worth of data were excluded to ensure that particles were thoroughly mixed and the laser attained its nominal condition. Each run consisted of 80000 horizontal lidar profiles. The lidar returns over distances to the lidar detector for each profile were in the range from z = 0 to 13 m and had a 0.28 m resolution. The summary table includes the heater power, mean current speed, Turbulent Kinetic Energy Dissipation (TKED), temperature dissipation, light attenuation and depolarization at 532nm. We used polarimetric lidar constructed for the project by the JPL/NASA PI Gary Spiers. The polarimetric lidar used was a Minilite II laser (Continuum Lasers) with a 0.025 J/pulse transmitted pulse energy, a 4 ns pulse length 4 ns, a 10 s-1 pulse repetition rate and 532nm wavelength. A Rockland Int. microstructure profiler (VMP200) was used to measure turbulence.

Suggested Citation:

Darek Bogucki. 2018. Dataset for: Polarimetric lidar measurements of aquatic turbulence - laboratory experiment. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7KP80SX

Publications:

Bogucki, D. J., Domaradzki, J. A., & von Allmen, P. (2018). Polarimetric lidar measurements of aquatic turbulence - laboratory experiment. Optics Express, 26(6), 6806. doi:10.1364/oe.26.006806

Purpose:

The data were collected to measure the turbulent flow optical depolarization coefficient gamma.

Data Parameters and Units:

Run name; Mean current speed (U, m/s); Heater power (P, kW); Turbulent kinetic energy dissipation (TKED, m^2/s^3); Temperature dissipation (TD, degrees C^2/s); Water light attenuation at 532 nm (alpha, 1/m); Relative alpha error corresponding to a 95.5% confidence interval (2sigma); Water light depolarization at 532 nm (gamma, 1/m); Relative gamma error corresponding to a 95.5% confidence interval (2sigma)

Methods:

The tank was filled with tap water without the addition of any particles during the first 2 runs (DEC31). During these two first runs, we observed the presence of debris particles of varying sizes after the pump had established the constant water flow speed. To eliminate the debris in subsequent runs, we emptied the tank and refilled it with clean tap water and then added 10 µm neutrally buoyant particles of varying concentration. For the rest of the runs, the tank was filled with clean tap water and seeded with varying concentrations of monodisperse 10µm neutrally buoyant beads.

Instruments:

Minilite II laser (Continuum Lasers)

Individual Files: