( youtube)Ī variant injects particles continuously into the jet and surpresses the color coding of velocity.
( mp4)Īnother version has 100 advected particles. There is also a particle (white disc) advected by the flow.
The region has walls top/bottom and is toroidally connected left/right. The second code implements a jet which pushes fliud to the right in a zero velocity medium. Laminar flow past the flat plate at lower omega (higher dynamic viscosity). A frame from the solution(mp4) is shown below with a von Karman vortex street in the wake of the flat plate at x=100. The Palabos code was used to understand the scaling of various constants, partcularly the relaxation constant, omega. The overall framework is from Haslam, but modified to use the simpler (no division) update function of Nowicki and Claesen. The first code is a mash-up of the three sources below. This slightly more detailed image is from Nicolas Delbosc labeling the density vectors. Discrete streams that go into boudary cells are returned to the originating cell in the oppposite directions. The image below is again from O'Brien 2008. (from O'Brien 2008 )īoundaries are handled by assuming 'no slip' conditions so that streams hitting a boundary cell are bounced back in the direction they came from. Streaming: The distribution for a cell is copied to the eight cells around it.
The images below were taken from O'Brien 2008 to show the propagation and collision steps. At any time step, eight densities from neighboring cells stream into a cell where they 'collide', are mixed, then on the next time step, stream to new cells. Constrains are placed on the densities to conserve momentum and mass. The fluid flow is abstracted into continuous-valued densities, flowing in eight discrete directions from a given cell, with zero velocity flow as a ninth flow. Nowicki and Claesen give one approach to implementing the FPGA hardware. Then build FPGA hardware and parallelize. First figure out the algorithm and tune it in matlab. The goal is to parallelize the LB calculation onto the FPGA, but there are a few steps to do first.
Lattice Boltzmann methods can be used to simulate fluid flow on a grid of cells.
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