streaklines

Compute particle streaklines on large unsteady flow datasets. Geometry tools are included to linear arrays of oscillating villi (to be published in an upcoming paper).

Setup

call setupPaths.m to add the code to the matlab path

Generating Unsteady Flow Datasets

This solver integrates unsteady vector fields saved on disk. Each timestep should be stored in a separate matlab binary .mat files named frame<i>.mat under some directory matDir/

Metadata

A metadata.mat file included in matDir/ indicates villi dimensions, pattern, time between frames etc. Examples are included in metadata/. experiment1Hz.mat matches my experiment whereas simulation1Hz.mat is matches Justin's example CFD sim. A metadata.mat file should include

• Pattern - villi pattern params
• Villi - villi dimensions. These are automatically scaled to sim units in Villi.m
• Tank - number of villi and spacing
• timeDelta - Constant time delta between frames

Converting Tecplot Ascii to Matlab Binary (.dat -> .mat)

Individual files are converted with parseTecplot.m. To batch a dataset, use dat2mat.m, which saves metadata.mat as well.

Frame Interpolator

The FrameInterpolator handle class interpolates a dataset with FIFO frame caching.

Solution

A Solution struct contains computed trajectories and data needed for integration (model of villi / interpolator / Settings / ...).

solution = trackParticles(solution, tSpan, outDir) performs integration by calling ode45 until the end of tSpan is reached. Individual calls to ode45 halt on particle crash events or to save data. Integrator settings are read from the solution struct, default settings are in Settings.m

Particle Tracking Setup

• Create a new solution with solution = Solution(matDir)
• Add particles using solution = addParticles(solution, xp, yp).
• Solve for particle trajectories solution = trackParticles(solution, tSpan, outDir)

Plotting and Rendering

• plotInitialCondition.m initial condition
• plotSolution.m trajectories/streaklines
• animate.m animates to solution to screen / renders video to files

src/plots/ contains plotting tools

Tests

Call tests.m to run tests. Currently checks a few streaklines in some very simple steady flows (horizontal / vertical / rigid body vortex)

Example Scripts

Checkout examples/ for some example scripts including batching tecplot conversion, and particle tracking with TSection and uniform grid particle formations.