Lattice Boltzmann equations using multiple relaxation times are intended to be more stable than those using a single relaxation time. The additional relaxation times may be adjusted to suppress non-hydrodynamic modes that do not appear directly in the continuum equations, but may contribute to instabilities on the grid scale. If these relaxation times are fixed in lattice units, as in previous ...

On-site boundary conditions are often desired for lattice Boltzmann simulations of fluid flow in complex geometries such as those of porous media or microfluidic devices. The possibility of specifying the exact position of the boundary, independently of other simulation parameters, simplifies the analysis of the system. For practical applications it should allow one to freely specify the direct...

We present an alternative way to determine the frictional forces at the contact between two particles. This alternative approach has its motivation in a detailed analysis of the bounds on the time integration step in Discrete Element Method (DEM) for simulating collisions and shearing of granular assemblies. We show that, in standard numerical schemes, the upper limit for the time integration s...

It is very natural to solve time dependent problems with Domain Decomposition Methods by using an implicit scheme for the time variable and then applying a classical iterative domain decomposition method at each time step. This is however not what the Schwarz Waveform Relaxation (SWR) methods do. The SWR methods are a combination of the Schwarz Domain Decomposition methods, see Schwarz [1870], ...

Based on the no-slip boundary condition for walls at rest for the lattice Boltzmann Bathnagar-Gross-Krook method by J.C.G. Verschaeve [10], a no-slip boundary condition for walls with a tangential movement is derived. Numerical tests verify that the present boundary condition is second order accurate and stable for relaxation frequencies close to two.

In his Ph.D. disseration, Feldman and his collaborators define the linear programming decoder for binary linear codes, which is a linear programming relaxation of the maximum-likelihood decoding problem. This decoder does not, in general, attain maximum-likelihood performance; however, the source of this discrepancy is known to be the presence of non-integral extreme points (vertices) within th...

It has long been known that some microswimmers seem to swim counter-intuitively faster when the viscosity of the surrounding fluid is increased, whereas others slow down. This conflicting dependence of the swimming velocity on the viscosity is poorly understood theoretically. Here we explain that any mechanical microswimmer with an elastic degree of freedom in a simple Newtonian fluid can exhib...

abstract background: self-esteem is a determinant factor of mental health. individuals with low self-esteem have depression, and low self-esteem is one of main symptoms of depression. aim of this study is to compare the effects of problem-solving skills and relaxation on the score of self-esteem in women with postpartum depression. materials and methods: this clinical trial was performed on 80 ...

In Multiple-Input Multiple-Output (MIMO) systems, Maximum-Likelihood (ML) decoding is equivalent to £nding the closest lattice point in an N dimensional complex space. In [1], we have proposed several quasimaximum likelihood relaxation models for decoding in MIMO systems based on semi-de£nite programming. In this paper, we propose randomization algorithms that £nd a near-optimum solution of the...

We apply lattice Boltzmann methods to study the relaxation of the velocity profile in binary fluids under shear during spinodal decomposition. In simple fluids, when a shear flow is applied on the boundaries of the system, the time required to obtain a triangular profile is inversely proportional to the viscosity and proportional to the square of the size of the system. We find that the same be...