A Critical Assessment of Resolution for Red-Blood-Cell Simulation

Simulations of deformable capsules in flow can require representation of a challengingly broad range of length scales. This is especially true for red blood cells, because they deform so significantly under physiological flow conditions. We discuss requisite simulation fidelity from the perspective of resolution, which we distinguish from the often-cited convergence order of a method. Resolution measures error at the finite discretization (e.g. mesh density) of actual simulations, and can therefore be a valuable metric in assessing methods for practical simulations. This is especially the case in chaotic multi-body cellular flow, for which the pertinent measures of convergence are statistical. Two model configurations are presented and analyzed using a particular high-resolution boundary integral solver: relaxation of a perturbed spherical capsule and the finite-deformation of a flowing red blood cell in a narrow round tube. Resolution needs depend strongly on the observable of interest.