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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Alexander Vikhansky Department of Engineering, Queen Mary, University of London
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Lattice-Boltzmann method
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Boltzmann equation
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows NS equations
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Plan of the presentation
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Plan of the presentation
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Knudsen number: Boltzmann equation
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Chapman-Enskog expansion
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Kinetic effects: 1. Knudsen slip (Kn), 2. Thermal slip (Kn). Knudsen layer (Kn 2 )
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Kinetic effects: 3. Thermal creep (Kn).
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Kinetic effects: 4. Thermal stress flow (Kn 2 ).
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Discrete ordinates equation
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Collision operator BGK model:
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Boundary conditions
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Boundary conditions: bounce-back rule
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Method of moments 1. Euler set: 2. Grad set: – 5 equations; – 13 equations; 3. Grad-26, Grad-45, Grad-71.
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Method of moments 1. Euler set: 2. Grad set: 3. Grad-26: 4. Grad-45, Grad-71: The error:
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Simulation of thermophoretic flows Velocity set:
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows M. Young, E.P. Muntz, G. Shiflet and A. Green Knudsen compressor
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Knudsen compressor
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows
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Effect of the boundary conditions
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Semi-implicit lattice-Boltzmann method for non-Newtonian flows From the kinetic theory of gases: Constitutive equation:
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Newtonian liquid: Bingham liquid: Semi-implicit lattice-Boltzmann method for non-Newtonian flows General case:
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Semi-implicit lattice-Boltzmann method for non-Newtonian flows Velocity set (3D): Velocity set (2D): Equilibrium distribution: Post-collision distribution:
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Semi-implicit lattice-Boltzmann method for non-Newtonian flows Bingham liquidPower-law liquid
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Flow of a Bingham liquid in a constant cross-section channel
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Creep flow through mesh of cylinders
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Flow through mesh of cylinders
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A. Vikhansky, Lattice-Boltzmann method for non-Newtonian and non-equilibrium flows Continuous in time and space discrete ordinate equation is used as a link from the LB to Navier-Stokes and Boltzmann equations. This approach allows us to increase the accuracy of the method and leads to new boundary conditions. The method was applied to simulation of a very subtle kinetic effect, namely, thermophoretic flows with small Knudsen numbers. The new implicit collision rule for non-Newtonian rheology improves the stability of the calculations, but requires the solution of a (one-dimensional) non-linear algebraic equation at each point and at each time step. In the practically important case of Bingham liquid this equation can be solved analytically. CONCLUSIONS
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