Efficient viscosity contrast calculation for blood flow simulations using the lattice Boltzmann method

Titelangaben

Lehmann, Moritz ; Müller, Sebastian Johannes ; Gekle, Stephan:
Efficient viscosity contrast calculation for blood flow simulations using the lattice Boltzmann method.
In: International Journal for Numerical Methods in Fluids. Bd. 92 (2020) Heft 11 . - S. 1463-1477.
ISSN 1097-0363
DOI der Verlagsversion: https://doi.org/10.1002/fld.4835

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Abstract

The lattice Boltzmann method (LBM) combined with the immersed boundarymethod is a common tool to simulate the movement of red blood cel ls (RBCs)through blood vessels. With very few exceptions, such simulations neglect thedifference in viscosities between the hemoglobin solution inside the cells andthe blood plasma outside, although it is well known that this viscosity contrastcan severely affect cell deformation. While it is easy to change the local vis-cosity in LBM, the challenge is to distinguish whether a given lattice point isinside or outside the RBC at each time step. Here, we present a fast algorithmto solve this issue by tracking the membrane motion and computing the scalarproduct between the local surface normal and the distance vector between theclosest LBM lattice point and the surface. This approach is much faster than,for example, the ray-casting method. With the domain tracking applied, weinvestigate the shape transition of a RBC in a microchannel for different vis-cosity contrast and validate our method by comparing with boundary-integralsimulations.