Flow structures generated by elongated plates settling in a water column

In order to establish a mathematical formulation of the equation of motion, the trajectory of particles settling in a stagnant fluid has been studied for generations. The publication by Field et al. [4] is one of the more well-known studies, where the dynamic behaviour of disks as function of the dimensionless moment of inertia and Reynolds number was investigated. The objective of the present work is to collect and present experimental data about the flow structures generated by the settling of elongated plates in a water column. The experiments are carried out by releasing the plates at an initial angle of 15° in a 0.60 m x 0.30 m 0.35 m (LBH) glass container filled with water. Continuous Particle Image Velocimetry is used to analyse both the velocity field of the continuous phase and the motion of the plates. The experiments show a well-defined oscillating motion of the plate. A stall occurs each time the plate changes horizontal direction of motion. The results show a flow building up when the plate accelerates and a vortex rolling off in each turn

General Observations of the Time-Dependent Flow Field Around Flat Plates in Free Fall

The free fall trajectories of flat plates are investigated in order to improve understanding of the forces acting on falling blunt objects. The long term goal is to develop a general applicable model to predict free fall trajectories. Numerically the free fall of a flat plate is investigated using a six degrees of freedom (6DOF) solver and a dynamic mesh. To validate the simulation, the trajectories of aluminium plates falling in water are recorded by digital camera recordings and compared to the simulation. The simulation is able to calculate the motion of the plate within each time step with high accuracy, and thereby allowing the whole trajectory to be predicted with fair accuracy. With the numerical model able to predict the free fall and the complex plate fluid interactions, fluids forces can be extracted for model development in future studies.</jats:p