We develop an approach for computing the hydrodynamic friction tensor and scalar friction coefficient for an aerosol fractal aggregate in the transition regime. Our approach involves solving the Bhatnagar-Gross-Krook equation for the velocity field around a sphere and using the velocity field to calculate the force on each primary sphere in the aggregate due to the presence of the other spheres...

Is it possible to solve Boltzmann-type kinetic equations using only a small number of particle velocities? We introduce a technique of solving kinetic equations with a (arbitrarily) large number of particle velocities using only a lattice Boltzmann method on standard, low-symmetry lattices. The renormalized kinetic equation is validated with an exact solution of the planar Couette flow at moder...

We present a class of asymptotic-preserving (AP) schemes for the nonhomogeneous Fokker–Planck–Landau (nFPL) equation. Filbet and Jin [16] designed a class of AP schemes for the classical Boltzmann equation, by penalization with the BGK operator, so they become efficient in the fluid dynamic regime. We generalize their idea to the nFPL equation, with a different penalization operator, the Fokker...

We apply the projection operator formalism to the problem of determining the asymptotic behavior of the lattice BGK equation in the hydrodynamic limit. As an alternative to the more usual Chapman-Enskog expansion, this approach offers many benefits. Most remarkably, it produces absolutely exact, though non-Markovian, hydrodynamic difference equations as an intermediate step. These are accurate ...

There are some hydrodynamic equations that, while their parent kinetic equation satisfies fundamental mechanical properties, appear themselves to violate mechanical or thermodynamic properties. This paper aims to shed some light on the source of this problem. Starting with diffusive volume hydrodynamic models, the microscopic temporal and spatial scales are first separated at the kinetic level ...

The effects of 13 weeks of liraglutide treatment on endocrine and 1 exocrine pancreas in male and female ZDF-rats 2 – A quantitative and qualitative analysis revealing no evidence of 3 drug induced pancreatitis 4 5 Running head: Liraglutide does not induce pancreatitis in the ZDF rat 6 7 *Niels Vrang,* Jacob Jelsing, *Lotte Simonsen, Andres Eskjær Jensen, Inger 8 Thorup, Henrik Søeborg and Lott...

In this paper we extend the micro-macro decomposition based asymptotic-preserving scheme developed in [3] for the single species Boltzmann equation to the multispecies problems. An asymptoticpreserving scheme for kinetic equation is very efficient in the fluid regime where the Knudsen number is small and the collision term becomes stiff. It allows coarse (independent of Knudsen number) mesh siz...

Rarefied gas flows through two-dimensional finite length capillaries are studied numerically with the goal of performance optimization of a nanomembrane-based Knudsen compressor. Both density and temperature gradient driven flows are considered in a wide range of Knudsen numbers from 0.05 to 75. The length-to-height ratios from 5 to 30 were examined. Three different wall temperature distributio...