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Computational Fluid Dynamics (CFD) is a well established and validated technique which is
widely used to investigate and optimize fluid flows in applications as diverse as Formula One
motor racing and filtration systems.
CFD is often used to complement or an alternative to experimental testing. It can quickly and
economically produce a large amount of information about a flow and is particularly attractive
when conditions are difficult to reproduce experimentally (for example, high pressure or
inaccessible flows). Most laminar and turbulent flows can be accurately reproduced by a
properly set up CFD simulation.
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In CFD, the volume of fluid being simulated is represented by a mesh of cells (the mesh
representing the fluid around a drill bit is shown opposite). The mesh, information on boundary
conditions and fluid properties are used by a numerical iterative solver program to generate a
solution. The solver calculates the fluid velocities, pressures and other variables within each
cell. The solutions are usually viewed using graphics programmes, known as post processors.
Examples can be seen in Figures 1 and 2, opposite.
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CFD has previously been used to model PDC drill bits but only on a limited basis because it has required significant
investments of time and expense. The complexity of a drill bit coupled with computing and meshing limitations had
precluded the use of highly detailed bit models. However, advances in computer hardware & software have
dramatically increased the number of engineering applications for CFD over the past six years.
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