Abstract:

The flow in the Langmuir cell experimental facility is characterized for each set of flow conditions using particle image velocimetry (PIV). Flow is produced in the facility by stepper motor-driven belts along the tank sidewalls which move at speeds from 5-50 cm/s. This dataset includes mean and standard deviation fields and the individual snapshot fields, for velocity and additional velocity-based variables (vorticity, shear, divergence, among others), obtained at belt speeds of 5, 10, 15, 30, and 50 cm/s. The dataset also includes the plain-view images of the mean and standard deviation velocity magnitude.

Suggested Citation:

Murphy, David and Carlowen Smith. 2021. Langmuir cell experimental facility flow characterization using particle image velocimetry (PIV). Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-9kgt-0d12

Purpose:

The flow fields in the Langmuir facility were characterized so that in future experiments (in which oil droplets will be injected into the facility) the baseline flow conditions affecting the oil droplet spatiotemporal distributions will be known.

Data Parameters and Units:

The individual image data files, averaged data files, and standard deviation files all have the parameters: x [mm], y [mm], Vx [m/s], Vy [m/s], vector choice [], vorticity [1/s], vector length [m/s], divergence [1/s], shear strength [1/s^2], swirl strength [1/s^2], isValid [boolean]. The individual image files have the additional parameters: Peak ratio, Correlation value, Particle size [counts], Uncertainty V [m/s], Uncertainty Vx [m/s], Uncertainty Vy [m/s]. The averaged data have the additional parameters: Average kinetic energy [(m/s)^2], Number of vectors [samples], Reynolds stress Rxx [(m/s)^2], Reynolds stress Rxy [(m/s)^2], Reynolds stress Rxz [(m/s)^2], Reynolds stress Ryy [(m/s)^2], Reynolds stress Ryz [(m/s)^2], Reynolds stress Rzz [(m/s)^2], Standard deviation Vx [m/s], Standard deviation Vy [m/s], Turbulent kinetic energy [(m/s)^2], Turbulent shear stress [(m/s)^2]. The standard deviation data have the additional parameters: number of vectors [n].

Methods:

The flow in the Langmuir tank, which had an inner working fluid chamber 35.74 cm x 10.16 cm x 72.5 cm (DxWxL), was seeded with nearly neutrally particles, and a light sheet was directed upwards through the tank bottom to illuminate the tank centerline. A camera was positioned orthogonal to the laser sheet, approximately 1.5 meters from the tank volume at mid-height. The camera was equipped with a 50 mm lens with a 33.6 degree (diagonal) field of view and was mounted with a horizontal viewing angle was approximately 28 degrees. Particle positions were recorded by the imaging system, and portions of consecutive image pairs were cross-correlated using the DaVis software package (LaVision Gmbh) to produce a series of two-dimensional instantaneous velocity fields. These velocity fields were then analyzed to calculate the mean and standard deviations of velocities. Velocity fields are calculated for belt speeds of 5, 10, 15, 30, and 50 cm/s.

Instruments:

Phantom VEO 640S/L, 50mm lens, 33.6 degree diagonal field of view. Sensor size is 15.6 x 16 mm with 2560 x 1600 pixels, for a pixel size of 10 microns. Exposure was 25,000 microseconds.

Individual Files: