Authors :
Masood Hemati; Nikolay Alekseevich Zabelin
Volume/Issue :
Volume 7 - 2022, Issue 7 - July
Google Scholar :
https://bit.ly/3IIfn9N
Scribd :
https://bit.ly/3zyxz37
DOI :
https://doi.org/10.5281/zenodo.6969529
Abstract :
We provide a scalable GPU code for droplet
motion in biphasic streams. This code solves the NavierStokes incompressibility equation for two-fluid systems
with a direct Poisson FFT solver based on the pressure
equation. The interface between the two fluids is shown
by the Volume Volume (VoF) method, which is suitable
for complex flows due to its capacity to manage
topological changes. The energy equation is explicitly
solved and coupled with the momentum equation via the
Bosinsk approximation. This code is modularly designed
to be able to use different numerical methods
independently, modify existing procedures, and combine
new ones simply and consistently. FluTAS is written in
Fortran and uses the MPI / OpenMP combination in the
CPU-only version in parallel, accelerating GPU
execution with OpenACC instructions. The two
dominant forces affecting droplet fracture, drag force,
and surface tensile force are confirmed using two
benchmarks: pressure distribution on a cylindrical
surface in uniform flow and oscillation of a square drop
under surface tensile force. The results show that the
failure process occurs in two steps. During the first stage,
the droplets are stretched and thinned perpendicular to
the direction of fluid flow. In the second stage, isolated
points appear on the surface of the droplets which are
attributed to the unstable growth of surface waves. The
topology of the droplet after failure depends on the value
of the Weber number: the larger the Weber number, the
more isolated points on the surface of the droplets.
Keywords :
Two-phase flows, Fluid volume method, Turbulence in multiphase flows, High-performance computing, OpenACC instructions
We provide a scalable GPU code for droplet
motion in biphasic streams. This code solves the NavierStokes incompressibility equation for two-fluid systems
with a direct Poisson FFT solver based on the pressure
equation. The interface between the two fluids is shown
by the Volume Volume (VoF) method, which is suitable
for complex flows due to its capacity to manage
topological changes. The energy equation is explicitly
solved and coupled with the momentum equation via the
Bosinsk approximation. This code is modularly designed
to be able to use different numerical methods
independently, modify existing procedures, and combine
new ones simply and consistently. FluTAS is written in
Fortran and uses the MPI / OpenMP combination in the
CPU-only version in parallel, accelerating GPU
execution with OpenACC instructions. The two
dominant forces affecting droplet fracture, drag force,
and surface tensile force are confirmed using two
benchmarks: pressure distribution on a cylindrical
surface in uniform flow and oscillation of a square drop
under surface tensile force. The results show that the
failure process occurs in two steps. During the first stage,
the droplets are stretched and thinned perpendicular to
the direction of fluid flow. In the second stage, isolated
points appear on the surface of the droplets which are
attributed to the unstable growth of surface waves. The
topology of the droplet after failure depends on the value
of the Weber number: the larger the Weber number, the
more isolated points on the surface of the droplets.
Keywords :
Two-phase flows, Fluid volume method, Turbulence in multiphase flows, High-performance computing, OpenACC instructions
