  To design a method to solve the issues of handling 'dirty' and highly complex
geometries, the topology-free method combined with the immersed boundary method
is presented for viscous and incompressible flows at a high Reynolds number.
The method simultaneously employs a ghost-cell technique and distributed
forcing technique to impose the boundary conditions. An axis-projected
interpolation scheme is used to avoid searching failures during fluid and solid
identification. This method yields a topology-free immersed boundary, which
particularly suits flow simulations of highly complex geometries. Difficulties
generally arise when generating the calculation grid for these scenarios. This
method allows dirty data to be handled without any preparatory treatment work
to simplify or clean-up the geometry. This method is also applicable to the
coherent structural turbulence model employed in this study. The verification
cases, used in conjunction with the second-order central-difference scheme,
resulted in first-order accuracy at finer resolution, although the coarser
resolution retained second-order accuracy. This method is fully parallelized
for distributed memory platforms. In this study, the accuracy and fidelity of
this method were examined by simulating the flow around the bluff body, past a
flat plate, and past dirty spheres. These simulations were compared with
experimental data and other established results. Finally, results from the
simulation of practical applications demonstrate the ability of the method to
model highly complex, non-canonical three-dimensional flows. The countermeasure
based on the accurate classification of geometric features has provided a
robust and reasonable solution.
