Viscoelastic Worthington Jets & Droplets Produced by Bursting Bubbles

This repository contains the simulation code and analysis for studying the dynamics of viscoelastic Worthington jets and droplets produced by bursting bubbles. The code uses the ElastoFlow framework to simulate bubble cavity collapse in viscoelastic media, examining how elastic modulus and relaxation time affect jet and droplet formation.

The article can be found at:

Overview

The project investigates how viscoelasticity influences bubble bursting dynamics by exploring the three-dimensional phase space of solvent Ohnesorge number, elastocapillary number, and Deborah number using volume of fluid-based finite volume simulations. The results demonstrate that polymer addition significantly influences the overall dynamics through the interplay of viscous and elastic effects.

Repository Structure

├── basilisk/src/               # Core Basilisk CFD library (reference only, do not modify)
├── src-local/                  # Custom viscoelastic solvers and tensor utilities
│   ├── log-conform-viscoelastic-scalar-3D.h   # 3D log-conformation (scalar)
│   ├── log-conform-viscoelastic-scalar-2D.h   # 2D/axi log-conformation (scalar)
│   ├── log-conform-viscoelastic.h             # 2D/axi log-conformation (tensor)
│   ├── two-phaseVE.h                          # Two-phase viscoelastic extension
│   └── eigen_decomposition.h                  # 3x3 symmetric eigenvalue solver
├── simulationCases/            # Example/test cases and post-processing scripts
│   ├── burstingBubbleVE.c                     # Bursting bubble simulation
├── postProcess/                # Project-specific post-processing tools and utilities
    ├── getData-elastic-scalar2D.c            # Data extraction utility
    ├── getFacet2D.c                          # Facet extraction utility
    ├── VideoAxi.py                           # Python visualization script

Installation and Setup

To ensure you have the necessary tools and a fresh Basilisk installation, use the provided script:

./reset_install_requirements.sh

Function

This script checks for Basilisk installation and compiles it if not present.

OS Compatibility

Designed for macOS. If you encounter issues on Linux, consider opening a GitHub issue.

Dependencies

• Basilisk C is fetched and built automatically.
• Xcode Command Line Tools (macOS) or equivalent compiler toolchain (Linux) are required.

Environment Setup

After running the script, a .project_config file is created, setting BASILISK and PATH automatically.

If you have previously installed Basilisk or changed dependencies, re-run the script with --hard:

./reset_install_requirements.sh --hard

Running the Code

Recommended Method: Using Makefile

The easiest way to compile and run the code is using the Makefile approach:

1. Navigate to the testCases directory:

cd testCases

2. Compile and run using make:

CFLAGS=-DDISPLAY=-1 make burstingBubbleVE.tst

Alternative Method: Direct Compilation

You can compile the code directly using qcc in two ways:

1. Using include paths (recommended):

qcc -O2 -Wall -disable-dimensions -I$(PWD)/src-local -I$(PWD)/../src-local burstingBubbleVE.c -o burstingBubbleVE -lm

2. Without include paths:

qcc -O2 -Wall -disable-dimensions burstingBubbleVE.c -o burstingBubbleVE -lm

Note: If using method 2, you must first manually copy the src-local folder to your running directory.

Local Execution

MacOS:

# First source the configuration
source .project_config

# Compile using include paths (recommended)
qcc -O2 -Wall -disable-dimensions -I$(PWD)/src-local -I$(PWD)/../src-local burstingBubbleVE.c -o burstingBubbleVE -lm

# Or compile without include paths (requires manually copying src-local folder)
qcc -O2 -Wall -disable-dimensions burstingBubbleVE.c -o burstingBubbleVE -lm

# Run the executable, only supports serial execution
./burstingBubbleVE

Linux:

# First source the configuration
source .project_config

# Compile using include paths (recommended)
qcc -O2 -Wall -disable-dimensions -fopenmp -I$(PWD)/src-local -I$(PWD)/../src-local burstingBubbleVE.c -o burstingBubbleVE -lm

# Or compile without include paths (requires manually copying src-local folder)
qcc -O2 -Wall -disable-dimensions -fopenmp burstingBubbleVE.c -o burstingBubbleVE -lm

# Set the number of OpenMP threads
export OMP_NUM_THREADS=4

# Run the executable
./burstingBubbleVE

HPC Cluster Execution (e.g., Snellius)

For cluster environments, it is strongly recommended to manually copy the src-local folder to your working directory to ensure reliable compilation across different cluster configurations:

1. First, copy the required files:

cp -r /path/to/original/src-local .

2. Compile the code for MPI:

CC99='mpicc -std=c99' qcc -Wall -O2 -D_MPI=1 -disable-dimensions burstingBubbleVE.c -o burstingBubbleVE -lm

3. Create a SLURM job script (e.g., run_simulation.sh):

#!/bin/bash

#SBATCH --nodes=1
#SBATCH --ntasks=32
#SBATCH --time=1:00:00
#SBATCH --partition=genoa
#SBATCH --mail-type=ALL
#SBATCH --mail-user=v.sanjay@utwente.nl

srun --mpi=pmi2 -n 32 --gres=cpu:32 --mem-per-cpu=1750mb burstingBubbleVE

4. Submit the job:

sbatch run_simulation.sh

Additional Running Scripts

The z_extras/running directory contains supplementary materials and post-processing tools used in the analysis. This includes C-based data extraction utilities, Python visualization scripts, and analysis notebooks. These tools were used to process simulation outputs and generate figures for the study. For detailed documentation of these tools, see the README in the z_extras directory.

Reset Install Requirements Script

The reset_install_requirements.sh script is designed to reset the installation requirements for the project. This can be useful when you want to ensure that all dependencies are fresh and up-to-date.

Purpose

The script re-installs all required packages as specified in the requirements file, ensuring that the project's dependencies are up-to-date and consistent.

Usage

To run the script, use the following command in your terminal:

bash reset_install_requirements.sh

Make sure to have the necessary permissions to execute the script.

Citation

If you use this code in your research, please cite:

Paper

@article{Dixit_Oratis_Zinelis_Lohse_Sanjay_2025, 
  title={Viscoelastic Worthington jets and droplets produced by bursting bubbles}, 
  volume={1010}, 
  journal={J. Fluid Mech.}, 
  author={Dixit, A. K. and Oratis, A. and Zinelis, K. and Lohse, D. and Sanjay, V.}, 
  year={2025}, 
  pages={A2},
  DOI={10.1017/jfm.2025.237}}

Software

@software{vatsal_sanjay_2024_14210635,
  author       = {Vatsal Sanjay},
  title        = {{comphy-lab/Viscoelastic3D: 🌊 v2.5: ElastoFlow - 
                   Complete 2D/3D Viscoelastic Framework}},
  month        = nov,
  year         = 2024,
  publisher    = {Zenodo},
  version      = {v2.5},
  doi          = {10.5281/zenodo.14210635},
  url          = {https://doi.org/10.5281/zenodo.14210635}
}

Features

• Simulation of bubble cavity collapse in viscoelastic media
• Analysis of Worthington jet formation and droplet ejection
• Investigation of polymer effects through:
  • Elastic modulus (elastocapillary number)
  • Relaxation time (Deborah number)
  • Viscous effects (Ohnesorge number)

Dependencies

The code utilizes:

• Basilisk C (basilliskpopinet)
• Volume of Fluid (VoF) method for interface tracking
• Adaptive Mesh Refinement (AMR) with quadtree grids

Key Results

The simulations reveal:

1. Three distinct flow regimes:
   • Jets forming droplets
   • Jets without droplet formation
   • Absence of jet formation
2. Impact of viscoelasticity on:
   • Capillary wave propagation
   • Jet elongation and retraction
   • Droplet formation and size

Additional Resources

The z_extras directory contains supplementary materials and post-processing tools used in the analysis. This includes C-based data extraction utilities, Python visualization scripts, and analysis notebooks. These tools were used to process simulation outputs and generate figures for the study. For detailed documentation of these tools, see the README in the z_extras directory.

Authors

• Ayush K. Dixit (University of Twente), a.k.dixit@utwente.nl
• Alexandros Oratis (University of Twente, now TU Delft), a.t.oratis@tudelft.nl
• Konstantinos Zinelis (Imperial College London, now MIT), zinelis@mit.edu
• Detlef Lohse (University of Twente & Max Planck Institute), d.lohse@utwente.nl
• Vatsal Sanjay (University of Twente), vatsalsanjay@gmail.com

License

This project is licensed under standard academic terms. Please cite the paper and software if you use this code in your research.