  This paper present a simulation strategy for DNS of turbulent co-current
Taylor bubble flow. This is a continuation of the work presented in [2] in
which Large Eddy Simulation (LES) of co-current turbulent Taylor bubble flow
was presented. It was observed that one of the main challenges is the
physically accurate prediction of the behavior of the Taylor bubble skirt, and
the related bubble shedding. An underestimation of the turbulent fluctuations
in the wake of the Taylor bubble was observed in the LES results. It was
suggested that this is related to over-prediction of the loss of void of the
Taylor bubble due to bubble shedding induced by an LES mesh resolution which is
not sufficient to capture the break-up and bubble formation accurately. To
counter this, in the current work we present a DNS approach of co-current
turbulent Taylor bubble flow called RK-Basilisk, based on the Basilisk code
with local adaptive grid refinement. This strategy allows for very high mesh
resolution near the bubble's interface while elsewhere the grid is allowed to
be coarser. Each time step, the mesh is adapted based on a void fraction
criterion. Basilisk's underlying data structure which is based on an 'octree'
allows for much faster solution procedures and, therefore, a much greater
number of grid points as compared to the LES simulations which were performed
using the more general OpenFOAM code. We compare the results against
experimental data of the same setting, as well as the co-current LES OpenFOAM
results. The setting of turbulent Taylor bubble flow in co-current conditions
allows for both lower order turbulence model development and the validation of
more general two-phase modeling strategies. Taylor bubble flow in itself also
bears relevance to specific two-phase flow situations. The current work
contributes to an advancement in simulation capability for such situations.
