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Lenz, S., Schoenherr, M., Geier, M., Krafczyk, M., Pasquali, A., Christen, A. and Giometto, M. (2019) Towards Real-Time Simulation of Turbulent Air Flow over a Resolved Urban Canopy Using the Cumulant Lattice Boltzmann Method on a GPGPU. Journal of Wind Engineering and Industrial Aerodynamics, 189, 151-162.
https://doi.org/10.1016/j.jweia.2019.03.012

has been cited by the following article:

• TITLE: A Direct Effective Viscosity Approach for Modeling and Simulating Bingham Fluids with the Cumulant Lattice Boltzmann Method

  AUTHORS: Martin Geier, Konstantin Kutscher, Manfred Krafczyk

  KEYWORDS: Lattice Boltzmann Method, Bingham Fluids, Generalized Equilibrium

  JOURNAL NAME: Open Journal of Fluid Dynamics, Vol.11 No.1, March 17, 2021

  ABSTRACT: Modeling of fluids with complex rheology in the lattice Boltzmann method (LBM) is typically realized through the introduction of an effective viscosity. For fluids with a yield stress behavior, such as so-called Bingham fluids, the effective viscosity has a singularity for low shear rates and may become negative. This is typically avoided by regularization such as Papanastasiou’s method. Here we argue that the effective viscosity model can be re-interpreted as a generalized equilibrium in which no violation of the stability constraint is observed. We implement a Bingham fluid model in a three-dimensional cumulant lattice Boltzmann framework and compare the direct analytic effective viscosity/generalized equilibrium method to the iterative approach first introduced by Vikhansky which avoids the singularity in viscosity that can arise in the analytic method. We find that both methods obtain similar results at coarse resolutions. However, at higher resolutions the accuracy of the regularized method levels off while the accuracy of the direct method continuously improves. We find that the accuracy of the proposed direct method is not limited by the singularity in viscosity indicating that a regularization is not strictly necessary.