  The transport and manipulation of particles and cells in microfluidic devices
has become a core methodology in domains ranging from molecular biology to
manufacturing and drug design. The rational design and operation of such
devices can benefit from simulations that resolve flow-structure interactions
at sub-micron resolution. We present a computational tool for large scale,
efficient and high throughput mesoscale simulations of fluids and deformable
objects at complex microscale geometries. The code employs Dissipative Particle
Dynamics for the description of the flow coupled with visco-elastic membrane
model for red blood cells and can also handle rigid bodies and complex
geometries. The software (MiRheo) is deployed on hybrid GPU/CPU architectures
exhibiting unprecedented time-to-solution performance and excellent weak and
strong scaling for a number of benchmark problems. MiRheo exploits the
capabilities of GPU clusters, leading to speedup of up to 10 in terms of time
to solution as compared to state-of-the-art software packages and reaches 90 -
99 percent weak scaling efficiency on 512 nodes of the Piz Daint supercomputer.
The software MiRheo, relies on a Python interface to facilitate the solution of
complex problems and it is open source. We believe that MiRheo constitutes a
potent computational tool that can greatly assist studies of microfluidics.
