# Viscoelastic Boundary Condition for D2Q9 Lattice

Hi,

I reimplemented the viscoelastic LBM described in Malaspinas: ‘LBM for the Simulation of Viscoelastic Fluids’. My aim is to use the D2Q9 lattice for the whole LB domain. Almost all equations can be adapted to this lattice except the equations of the conformation tensor boundary condition described in section 5.2.3.

Now I am searching for a conformation tensor boundary condition for the D2Q9 lattice.

Kind regards,
Matthias

hi
i am trying to generate LBM code for non-newtonian fluids.but i am facing problems with calculation shear rate at each grid point in order to calculate the apparent viscosity at each node

Hey Sivaiit,
I am also working on the same topic adn facing exactly the same problem as yours of not being able to calculate the shear rate at each node. Let me knwo what is the exact problem you’re facing, maybe we both can help each other out with thhis problem.

Piyush

Hi piush
i am trying simulation of non newtonian fluids using LBM.actually i am facing the problem with the algorith.if u want to calculate strain rate tensor we need to know the relaxation factor.so what relaxation factor we have to give initially.i have tried with initial relaxation factor with 1.i am getting the results but error was 3-5%.coluld you give me guidance in this aspect…

## Hi i am trying simulation of non newtonian fluids (power law fluids)using LBM.actually i am facing the problem with the algorithm.if I we want to calculate strain rate tensor we need to know the relaxation factor.so what relaxation factor we have to give initially.i have tried with initial relaxation factor with 1.i am getting the results but error was 3-5%.coluld you give me guidance in this aspect… mm_911 Wrote:

Hi,

I reimplemented the viscoelastic LBM described in
Malaspinas: ‘LBM for the Simulation of
Viscoelastic Fluids’. My aim is to use the D2Q9
lattice for the whole LB domain. Almost all
equations can be adapted to this lattice except
the equations of the conformation tensor boundary
condition described in section 5.2.3.

Now I am searching for a conformation tensor
boundary condition for the D2Q9 lattice.

Kind regards,
Matthias