pySurfaceEvolver

A Python frontend to Ken Brakke’s Surface Evolver. Surface Evolver finds surfaces of least energy: soap films, bubbles, drops on walls, liquid bridges, solder joints. pySE runs the engine in-process. Surfaces are built from NumPy arrays and come back as NumPy arrays, ev.relax() takes them to an equilibrium and says how it went, and the results can be plotted with PyVista and written out for finite-element meshing.

Where to start

• New here? Getting started installs pySE, puts a drop on a table and sets out the conventions every other page uses. The Tutorial: a double bubble, from arrays to FEM mesh then takes one problem, a double bubble, from arrays to a finite-element mesh, and A tour of the API lists the main calls on one page.

• Relaxing a surface explains what relax() does, how to read its result, and where its defaults stop working. Read it before the examples, or when a result looks wrong.

• The examples add one thing at a time: contact angles on curved solids (Example: a liquid bridge between two beads), forces and optimizing parameters from Brakke’s datafiles (Solder joints: force, standoff and alignment), several walls and mirror planes (Example: a droplet next to a bead in a slit), and a long quasi-static run (Example: draining liquid from a bead chain in a slit), following a bridge through its instability and fold (Where a shrinking bridge breaks), and liquid in throats and pores of a sphere packing (Liquid in a sphere packing).

• Classic results from the literature, each against an exact reference: the stability limits of a bridge between two disks (A liquid bridge between two disks), the largest drop a ring can hold (The largest drop a ring can hold), drops on one, two and crossed fibres (Drops on fibres), and a lens floating on a liquid (A lens floating on a liquid).

• Brakke’s sample datafiles run as they come, each with his own recipe and with relax() side by side: a gallery of what Evolver can model.

• The reference has the API, fourteen stress cases with exact references, performance numbers, and how to build and test pySE (Development).

Getting started

• Getting started
  • Install
  • A drop on a table
  • Conventions
  • Energies
  • A surface tension other than 1
  • How accurate are the contact angles?
  • Where next
• Tutorial: a double bubble, from arrays to FEM mesh
  • 1. Build the starting surface
  • 2. Relax
  • 3. High-order final stage
  • 4. Export for finite elements
  • Next
• A tour of the API
  • Scripting
  • Parameter sweeps
  • Building surfaces in Python
  • Visualization (PyVista)
  • Mesh files
  • Threads
  • Errors and interrupts
  • Limitations

Guides

• Relaxing a surface
  • What relax() does
  • Reading the result
  • Mesh resolution
  • Where the defaults stop working
  • Next
• Several surfaces at once
  • Drops side by side
  • What crosses between the processes
  • Starting, stopping and threads
  • Limits

Examples

• Example: a liquid bridge between two beads
  • The model
  • Relaxing
  • Checking the result
  • Profiles for several contact angles
  • Force against gap
  • How far a bridge stretches
  • Exporting for finite elements
  • Notes and limits
  • Further reading
  • Next
• Solder joints: force, standoff and alignment
  • The joint
  • The force on the upper pad
  • Force against height
  • How high a loaded chip floats
  • A chip that pulls itself into line
  • Next
• Example: a droplet next to a bead in a slit
  • The model
  • Relaxing
  • Checking the result
  • Varying the wall contact angle
  • Exporting for finite elements
  • Notes and limits
  • Next
• Example: draining liquid from a bead chain in a slit
  • The immersed start
  • Draining at \(\ell = 1.1\)
  • Pressure and curvature
  • Three spacings
  • Movies
  • Related work
  • Next
• Where a shrinking bridge breaks
  • Shrinking through the fold
  • The reference
  • Along the off-centre bridges
  • What it means
  • References
• Liquid in a sphere packing
  • Gas passing a throat
  • Three beads: where a trimer bursts
  • Five degrees: snap-in, pop-out and the dimer
  • A pore full of liquid
  • Pictures
  • Notes and limits
  • References
• A liquid bridge between two disks
  • The bridge
  • Taking liquid away
  • Adding liquid
  • With gravity
  • Pictures
  • Notes and limits
  • References
• The largest drop a ring can hold
  • Growing a drop to its largest
  • Wide rings: tipping sideways
  • Notes and limits
  • References
• Drops on fibres
  • One fibre: where a barrel rolls up
  • The clam shell
  • Two parallel fibres: the column
  • Crossed fibres
  • Pictures
  • Notes and limits
  • References
• A lens floating on a liquid
  • Three tensions
  • Without gravity: two caps
  • With gravity: a puddle
  • Pictures
  • Notes and limits
  • References

Brakke's samples

• Brakke’s samples: soap films and foams
• Brakke’s samples: drops and capillarity
• Brakke’s samples: crystals and elastic membranes
• Brakke’s samples: strings, metrics and other dimensions
• Brakke’s samples: quadratic and Lagrange elements

Reference

• API reference
• Stress cases
• Performance
• Development