Elastic Impactor Hitting a Viscous Liquid Film

This repository contains code for simulating the dynamics of an elastic spherical impactor falling onto a viscous liquid film. The simulation is implemented in 2D+axi (axisymmetric) configuration using the Basilisk framework.

Background

The simulation models a viscoelastic scalar implementation of a spherical impactor falling onto a viscous liquid film. The physics includes:

• Two-phase flow with surface tension
• Viscoelastic effects
• Axisymmetric geometry
• Fluid-structure interaction

Implementation

Key Files

• testCases/sphereFilm_catch.c: Main simulation file implementing the physics
• testCases/VideoAxi.py: Post-processing script for visualization
• src-local/log-conform-viscoelastic-scalar-2D.h: Viscoelastic solver implementation
• src-local/two-phase-TF-VE.h: Two-phase flow implementation

Key Parameters

• We: Weber number (ratio of inertial to surface tension forces)
• Ohd: Ohnesorge number for the droplet (ratio of viscous to inertial and surface tension forces)
• Ec: Elastic parameter
• De: Deborah number (ratio of relaxation time to observation time)
• Ohf: Ohnesorge number for the film
• hf: Film thickness
• Bo: Bond number (ratio of gravitational to surface tension forces)

Numerical Methods

• Grid: Adaptive mesh refinement with levels from MINlevel (4) to MAXlevel (10)
• Time integration: Centered Navier-Stokes solver
• Interface tracking: Volume-of-Fluid method with tension
• Error tolerances:
  • Fraction error: 1e-3
  • Velocity error: 1e-3
  • Kinetic energy error: 1e-3
  • Area error: 1e-3

Usage

Compilation

The code requires the Basilisk framework. Compile using:

qcc -Wall -O2 -o sphereFilm_catch sphereFilm_catch.c -lm

Running Simulations

Execute the compiled binary with appropriate parameters:

./sphereFilm_catch [parameters]

Post-processing

Use the VideoAxi.py script for visualization:

python VideoAxi.py [options]

Post-processing Scripts

VideoAxi.py

A Python script for creating visualizations of the simulation results. Features:

• Custom color mapping for different phases
• Facet extraction for interface visualization
• Field data extraction and plotting
• Multi-processing capabilities for faster rendering

Dependencies

• Basilisk framework
• Python libraries:
  • NumPy
  • Matplotlib
  • Subprocess
  • Multiprocessing
  • Argparse

Author

Vatsal Sanjay ([email protected]) Physics of Fluids

Version History

• Version 1.0 (December 5, 2024): Initial release