Accelerating and parallelizing Lagrangian simulations of mixing-limited reactive transport

Abstract

Recent advances in random-walk particle-tracking have enabled direct simulation of mixing and reactions on particles by allowing the particles to interact with each other using a multi-point mass transfer scheme. The mass transfer scheme allows separation of mixing and spreading processes, among other advantages, but it is computationally expensive because its speed depends on the number of interacting particle pairs. This note explores methods for relieving the computational bottleneck caused by the mass transfer step, and we use these algorithms to develop a new parallel, interacting particle model. The new model is a combination of a sparse search algorithm and a novel domain-decomposition scheme, both of which offer significant speedup relative to the reference case--even when they are executed serially. We combine the strengths of these methods to create a parallel particle scheme that is highly accurate and efficient with run times that scale as $1/P$ for a fixed number of particles, where $P$ is the number of computational cores being used. The new parallel model is a significant advance because it enables efficient simulation of large particle ensembles that are needed for environmental simulations, and also because it can naturally pair with parallel geochemical solvers to create a practical Lagrangian tool for simulating mixing and reactions in complex chemical systems.

arXiv comment29 pages, 4 figures

References in corpus (2)

• KDTREE 2: Fortran 95 and C++ software to efficiently search for near neighbors in a multi-dimensional Euclidean space
• On the accuracy of simulating mixing by random-walk particle-based mass-transfer algorithms

Cited by in corpus (5)

• Particle Density Estimation with Grid-Projected Adaptive Kernels
• Nonparametric, data-based kernel interpolation for particle-tracking simulations and kernel density estimation
• A Mass-transfer Particle-tracking Method for Simulating Transport with Discontinuous Diffusion Coefficients
• Reactive Particle-tracking Solutions to a Benchmark Problem on Heavy Metal Cycling in Lake Sediments
• A new flow-kinematics-based model for time-dependent effective dispersion in mixing-limited reactions