Topology-free immersed boundary method for incompressible turbulence flows: An aerodynamic simulation for dirty CAD geometry

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. (C) 2021 Elsevier B.V. All rights reserved. Superscript/Subscript Available

Automated summary

The method proposed in this study combines the topology-free method and the immersed boundary method, which is suitable for viscous and incompressible flows at high Reynolds numbers, particularly for handling dirty and highly complex geometries. By utilizing ghost-cell technique and distributed forcing technique for boundary conditions imposition, along with an axis-projected interpolation scheme to avoid searching failures, the method achieves a topology-free immersed boundary, making it ideal for flow simulations of intricate geometries.