Basic examples

These three examples are adapted from the "learning by examples" section in the FreeFem documentation. They are designed to demonstrate the basic features of Stabfem for interfacing FreeFem++ programs and plotting results.

• First example : membrane
• Second example : heat exchanger

• Third example : unsteady heat conduction

Thermal Conduction in a L-Shape domain

This next example shows how to solve several elementary problems, import, plot, combine the results, adapt the meshes, and use the Data Base manager.

• See program

Fluid-structure interaction problem

This example shows, through a simple problem consisting of a beam placed on top of a lid-driven cavity, how to manage problems involving several meshes within StabFem.

• See program

Linear stability analysis of the wake of a cylinder

These two scripts demonstrates how to use StabFem to perform the basis steps of a linear stability analysis : generation of an adapted mesh, computation of a base flow, computation of eigenmodes, and plotting the results. Two versions of the script are provided; the first uses single-core solvers, the second is an improved version using parallel (multi-core) solvers.

• Using single-core solvers
• Using multicore solver

Parametric study of the instability of a rotating cylinder

These examples show how to perform a parametric linear stability study. The considered problem is the wake of a rotating cylinders. The programs determine the marginal stability curve in the Re/Omega plane. Two methods are demonstrated here : the double-scan method and the direct threshold determination method. For each method, two scripts are provided, using either single-core or multicore solvers.

• Scan, Single-core
• Scan, Multicore

• Threshold, Single-core
• Threshold , Multicore

Acoustic pipes

This example demonstrates how to use StabFem to solve a linear acoustics problem, namely wave radiation from a cylindrical pipe opening to a semi-infinite domain.

• See program

Sloshing

This example shows how to use StabFem to compute eigenmodes in a free-surface problem

• See program

Unsteady heat conduction (II)

This example demonstrates the usage of the divers SF_TS_Launch and SF_TS_Check for time-stepping simulations.

• See program

Direct Numerical Simulation (DNS) of the wake of a cylinder

This example shows how to use StabFem to perform a DNS, using global stability computations to generate a suitable mesh and initial condition.

• See program

Falling ellipse

This example shows how to use the StabFem drivers for a time-stepping simulation with a dynamically adapted mesh. The example is taken from the examples available in the freefem documentation.

• See program

Parallel computing with PETSc

This example shows through a simple example you how to modify your FreeFem programs to run on multiple processors using PETSc, and how to launch them through StabFem.

• Simple program

Coupling with gmsh

This example shows you how to work with a mesh generated using the gmsh software

• See program

Wake of a cylinder

These three programs reproduce all the figures from the review paper

A practical review on linear and nonlinear global study of fluid flow instabilities" by D. Fabre et al.

• Main program (incompressible, sections 3 & 5) See program
• Mesh validations (appendix B) See program
• Program for compressible results (section 4) See program

• View related article

Linear oscillations of a liquid bridge

This program reproduces the main results of the following research paper : "Oscillations of a liquid bridge resulting from the coalescence of two droplets", by V. Chireux, D. Fabre, F. Risso & P. Tordjemann (Phys. Fluids, 27(6):062103, 2015)

• See program
• View related article

Rotating-polygon instability of a free-surface swirling potential flow

This program reproduces the main results of the following research paper : "On the instabilities of a potential vortex with a free surface", by J. Mougel, D. Fabre, L. Lacaze & T. Bohr (J. Fluid Mech. 824, 230-264 2018)

• See program
• View related article

Flow around a rotating cylinder using Arclength continuation.

This program reproduces figure 3(c) of the following research paper : "Bifurcation scenario in the 2D flow pasty a rotating cylinder", by J. Sierra, D. Fabre, V. Citro & F. Giannetti (J. Fluid Mech., 2020)

• See program
• View related article

Pulsated jet flow through a circular aperture of zero thickness

This program reproduces the time-stepping simulations of section 6 of the research paper : "The acoustic impedance of a laminar viscous jet througha thin circular aperture" by David Fabre, Raffaele Longobardi, Paul Bonnefis, Paolo Luchini (JFM, 2018)

• Sample results (time-stepping)
• View related article

Instability of the jet flow through a circular aperture of finite thickness

This program reproduces the main results of the following research paper : "Acoustic and hydrodynamical instability of the jet flow through a finite thicnkess hole" by D. Fabre, R. Longobarddi, V. Citro & P. Luchini (JFM, 2020)

• Sample results for aspect ratio 0.3
• Sample results for aspect ratio 1

• View related article

Impedance and instability properties of a spring-mounted cylinder

This program reproduces figures 3 and 4 of the following research paper : "Vortex-induced vibration predition via an impedance criterion", by D. Sabino, D. Fabre, J. Leontini & D. Lo Jacono (J. Fluid Mech., 2020)

• See program
• View related article

Computation of ionic wind due to corona discharge

This program reproduces a few figures of the following research paper : "Numerical study of ElectroAeroDynamic force and current resulting from ionic wind in emitter/collector systems", Coseru, S., Fabre, D., & Plouraboué, F., Journal of Applied Physics, 129(10), 2021.

• See program
• View related article