952 research outputs found
Schwarz alternating domain decomposition approach for the solution of mixed heat convection flow problems based on the method of approximate particular solutions
The incompressible two-dimensional Navier-Stokes equations including thermal
energy balance equation are solved by the recently developed Method of Approximate
Particular Solutions (MAPS). In a previous authors’ work this method was implemented
to solve the two-dimensional Stokes equations by employing the pressure and velocity particular
solutions obtained by Oseen’s decomposition with the Multiquadric (MQ) RBF
as non-homogeneous term. A pressure-velocity linkage strategy is not required since the
pressure particular solutions are obtained from the velocity ones. In the present contribution,
the Navier-Stokes equations with Boussinesq approximation are solved by linearizing
the convective term in a Picard iterative scheme. With the velocity values obtained at
each of the Picard iterations, the energy conservation equation is solved by the MAPS by
approximating temperature with the particular solutions of a Poisson problem with the
MQ as a forcing term. With the aim of improving the computational efficiency of the
global strategy, the two-dimensional domain is split into overlapped rectangular subdomains
where the Schwarz Alternating Algorithm is employed to find a solution by using
velocity and temperatures values from neighbouring zones as boundary conditions. The
mixed convection lid-driven cavity flow problem is solved for moderate Reynolds and low
Richardson numbers with the aim of validating the proposed method
Coupling Lattice Boltzmann and Molecular Dynamics models for dense fluids
We propose a hybrid model, coupling Lattice Boltzmann and Molecular Dynamics
models, for the simulation of dense fluids. Time and length scales are
decoupled by using an iterative Schwarz domain decomposition algorithm. The MD
and LB formulations communicate via the exchange of velocities and velocity
gradients at the interface. We validate the present LB-MD model in simulations
of flows of liquid argon past and through a carbon nanotube. Comparisons with
existing hybrid algorithms and with reference MD solutions demonstrate the
validity of the present approach.Comment: 14 pages, 5 figure
Spectral methods for CFD
One of the objectives of these notes is to provide a basic introduction to spectral methods with a particular emphasis on applications to computational fluid dynamics. Another objective is to summarize some of the most important developments in spectral methods in the last two years. The fundamentals of spectral methods for simple problems will be covered in depth, and the essential elements of several fluid dynamical applications will be sketched
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