# On the use of reverse Brownian motion to accelerate hybrid simulations

## Abstract

Multiscale and multiphysics simulations are two rapidly developing fields of scientific computing. Efficient coupling of continuum (deterministic or stochastic) constitutive solvers with their discrete (stochastic, particle-based) counterparts is a common challenge in both kinds of simulations. We focus on interfacial, tightly coupled simulations of diffusion that combine continuum and particle-based solvers. The latter employs the reverse Brownian motion (rBm), a Monte Carlo approach that allows one to enforce inhomogeneous Dirichlet, Neumann, or Robin boundary conditions and is trivially parallelizable. We discuss numerical approaches for improving the accuracy of rBm in the presence of inhomogeneous Neumann boundary conditions and alternative strategies for coupling the rBm solver with its continuum counterpart. Numerical experiments are used to investigate the convergence, stability, and computational efficiency of the proposed hybrid algorithm.

- Authors:

- Publication Date:

- OSTI Identifier:
- 22622268

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Computational Physics; Journal Volume: 334; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCURACY; ALGORITHMS; BOUNDARY CONDITIONS; BROWNIAN MOVEMENT; COMPUTERIZED SIMULATION; CONVERGENCE; COUPLING; DIFFUSION; DIRICHLET PROBLEM; EFFICIENCY; MONTE CARLO METHOD; PARTICLES; STABILITY; STOCHASTIC PROCESSES

### Citation Formats

```
Bakarji, Joseph, and Tartakovsky, Daniel M., E-mail: tartakovsky@stanford.edu.
```*On the use of reverse Brownian motion to accelerate hybrid simulations*. United States: N. p., 2017.
Web. doi:10.1016/J.JCP.2016.12.032.

```
Bakarji, Joseph, & Tartakovsky, Daniel M., E-mail: tartakovsky@stanford.edu.
```*On the use of reverse Brownian motion to accelerate hybrid simulations*. United States. doi:10.1016/J.JCP.2016.12.032.

```
Bakarji, Joseph, and Tartakovsky, Daniel M., E-mail: tartakovsky@stanford.edu. Sat .
"On the use of reverse Brownian motion to accelerate hybrid simulations". United States.
doi:10.1016/J.JCP.2016.12.032.
```

```
@article{osti_22622268,
```

title = {On the use of reverse Brownian motion to accelerate hybrid simulations},

author = {Bakarji, Joseph and Tartakovsky, Daniel M., E-mail: tartakovsky@stanford.edu},

abstractNote = {Multiscale and multiphysics simulations are two rapidly developing fields of scientific computing. Efficient coupling of continuum (deterministic or stochastic) constitutive solvers with their discrete (stochastic, particle-based) counterparts is a common challenge in both kinds of simulations. We focus on interfacial, tightly coupled simulations of diffusion that combine continuum and particle-based solvers. The latter employs the reverse Brownian motion (rBm), a Monte Carlo approach that allows one to enforce inhomogeneous Dirichlet, Neumann, or Robin boundary conditions and is trivially parallelizable. We discuss numerical approaches for improving the accuracy of rBm in the presence of inhomogeneous Neumann boundary conditions and alternative strategies for coupling the rBm solver with its continuum counterpart. Numerical experiments are used to investigate the convergence, stability, and computational efficiency of the proposed hybrid algorithm.},

doi = {10.1016/J.JCP.2016.12.032},

journal = {Journal of Computational Physics},

number = ,

volume = 334,

place = {United States},

year = {Sat Apr 01 00:00:00 EDT 2017},

month = {Sat Apr 01 00:00:00 EDT 2017}

}