Fluid flows often consist of multiple bodies either filling most of the flow domain
(for instance, porous media) or grouped in localized regions. Flow through localized
groups containing many bodies has, hitherto, had little detailed study. The primary
objective was to develop and trial new numerical and experimental procedures that
make possible detail studies of complex multibody flows. The research investigates
flow through a circular array of fixed size and populated by different numbers of
equally spaced cylinders, allowing the void fraction (φ) to be varied.
The main contribution is a detailed fully-resolved two-dimensional numerical calculation
of flow past arrays containing from 1 to 133 cylinders, where the array
Reynolds number is 2100. To produce this, a parallel computational code has been
written, specifically for a supercomputer, in general object-orientated language using
late binding and high performance numerical libraries (PETSc, MKL and ParaMETIS).
New diagnostics were applied to understand the array’s influence on the flow
through and around the array. A linear model was used to interpret the results.
An experimental apparatus was designed to measure and vizualize the flow field
and force contributions from an array fixed in a uniform flow. The design concept
(including the flume, instrument array and electronics) was tested and optimized
using CFD and FEA. The experimental results provide insight into the difference
between two- and three-dimensional flow patterns.
Case studies and experiments have generated data and graphical images at a level
of resolution not previously possible. Three distinct regimes have been identified. For
low φ, the interaction between the individual cylinders is weak. For intermediate φ,
a shear layer is created and stabilized by the bleed flow through the group, resulting
in steady forces on the group. For high φ, strong blocking occurs and the array acts
like a solid cylinder
