# Low-resolution simulations of vesicle suspensions in 2D

## TL;DR

This paper develops a low-resolution simulation scheme for vesicle suspensions that is faster and maintains accuracy, by systematically integrating empirical fixes to improve stability and physical fidelity.

## Contribution

It introduces a systematic low-resolution correction algorithm (LRCA) for vesicle suspension simulations, enhancing efficiency and accuracy over previous methods.

## Key findings

- LRCA enables 10x to 100x faster simulations.
- Low-resolution simulations remain statistically accurate.
- The scheme effectively handles dense suspensions and vesicle interactions.

## Abstract

Vesicle suspensions appear in many biological and industrial applications. These suspensions are characterized by rich and complex dynamics of vesicles due to their interaction with the bulk fluid, and their large deformations and nonlinear elastic properties. Many existing state-of-the-art numerical schemes can resolve such complex vesicle flows. However, even when using provably optimal algorithms, these simulations can be computationally expensive, especially for suspensions with a large number of vesicles. In this paper, we investigate the effect of a number of algorithmic empirical fixes in an attempt to make low-resolution simulations more stable and more predictive. Based on our empirical studies for a number of flow configurations, we propose a scheme that attempts to integrate these fixes in a systematic way. This low-resolution scheme is an extension of our previous work Quaife and Biros (2014) and Quaife and Biros (2016). Our low-resolution correction algorithms (LRCA) include anti-aliasing and membrane reparametrization for avoiding spurious oscillations in vesicles' membranes, adaptive time stepping and a repulsion force for handling vesicle collisions and, correction of vesicles' area and arc-length for maintaining physical vesicle shapes. We perform a systematic error analysis by comparing the low-resolution simulations of dilute and dense suspensions with their high-fidelity, fully resolved, counterparts. We observe that the LRCA enables both efficient and statistically accurate low-resolution simulations of vesicle suspensions, while it can be 10x to 100x faster.