Emulator of PR-DNS: Part II, Accelerating thermodynamics and cloud
droplet fields with machine learning in Particle-Resolved Direct
Numerical Simulation
Abstract
Particle-resolved direct numerical simulations (PR-DNS) are crucial for
unraveling the intricate interplay of aerosol-cloud-turbulence
processes. However, such models are challenged by the huge computational
cost due to the extremely high resolution. Our prior work showcased that
leveraging machine learning emulators could slash computational expenses
by two orders of magnitude while maintaining remarkable precision for
dynamic fields, and exhibited generalizability across diverse initial
conditions and at super-resolution scales without retraining the
emulators. Building upon this foundation, this work extends the
emulator’s application to thermodynamic in the two spatial dimensions
and droplet fields in the three spatial dimensions. Furthermore, to
enhance the robust generalizability of the emulator for different
initial values and super resolution, we introduce a novel multi-initial
learning approach for the neural operator method. For the droplet
fields, we introduce a novel loss function tailored to assess
distribution differences using the Mallows distance, focusing
particularly on droplet size distributions. Our findings indicate that
the machine learning emulators hold promising potential to effectively
mimic numerical PR-DNS simulations, thereby significantly advancing our
understanding of the complex interactions within
aerosol-cloud-turbulence processes.