Simulations, numerical experiments and visual results

This video presents a high-resolution Finite Element Method (FEM) simulation of a two-phase flow system at the onset of coalescence, highlighting the oscillatory interaction that develops as the interfaces approach each other before merging. The color field represents the magnitude of the vertical velocity, where red...

Numerical simulation of a light, deformable bubble rising under gravity in a sinusoidally modulated channel (width = 8.0, height = 0.5, amplitude = 0.07, wavelength = 2.0). The bubble (rho = 0.001, mu = 0.01) displaces a heavier, more viscous fluid (rho = 1.0, mu = 1.0) under gravity g = 9.81, with surface tension...

This video shows the difficult modeling of the coalescence process using the interface tracking technique in quadrilateral meshes. As can be seen, after the initial coalescence of bubbles, the bubble flow speed increases dramatically and the bubble interfaces collapses. After this point, the numerical simulation is no...

This test shows the deceleration of a rising bubble due to the distance between lateral walls. As can be seen, the larger is the channel width the faster is the rising bubble. The right hand side figure does not even arrive at the middle of the channel length for the exactly same parameters and time step to all...

Numerical simulation using the Finite Element method for 2D Two-Phase flows with deformable interface in arbitrary quadrilateral mesh. Non-dimensional parameters of the simulation: Re = 10 # Reynolds We = 10 # Weber Fr = 1.0 # Froude dynamic viscosity ratio = 2 density ratio = 100

This animations show the effect of the Laplacian Smoothing operation on quadrilateral mesh in a rectangular domain. Such a mesh is commonly used in Finite Element Analysis and can be further employed in single- and two-phase flow simulations. The main advantage of arbitrary quadrilateral meshes over triangular meshes...

This animations show the effect of the Laplacian Smoothing operation on quadrilateral mesh in a rectangular domain. Such a mesh is commonly used in Finite Element Analysis and can be further employed in single- and two-phase flow simulations. The main advantage of arbitrary quadrilateral meshes over triangular meshes...

This video shows a 2D passive particle transport of 200 particles in a channel with an obstacle. The motion is only given by the update position differential equation X^n+1 = X^n + v * dt, where n+1 is the future postion, n is the current position and v is the flow velocity, which does not depend on the particle's...

The video shows the numerical simulation of bloodstream flow in coronary artery with drug-eluting stents implanted to reduce buildup of fat deposition. The simulation was made using the Finite Element method and an unstructured triangular mesh and high order interpolation. The results reveal an interesting drug...

This is a numerical simulation of slug flow in sinusoidal channel using the finite element method and the moving-mesh/moving-boundary technique found in (https://doi.org/10.1016/j.cma.2020.112820). As can be seen 3 confined drops are flowing thru the corrugated channel and its cross-sectional variation changes the...

This animation shows the solution of a 2-dimensional flow jet stream during conversation of a human being possible contaminated with COVID-19. This study aims at investigate the persistence of a certain number of droplets with viral load in air.

This video shows the collisions of several particles with different sizes in a closed rectangular domain. Momentum is conserved in an isolated system with full elastic shocks between particles with different mass. As can be seen in this model, the heavier particles do not change their velocities too much with...

This movie shows the numerical solution of an initially spherical air bubble in a quiescent water-sugar solution using a moving frame view point where the bubble's centroid remains fixed in space while fluid flows downward. In this approach, the interface mesh is built as a set of interconnected nodes and finite...

VIVALE - Vortex-induced vibration using Arbitrary Lagrangian-Eulerian Finite Element Method for 2D simulation. In this video, the cylinder motion is controlled by a simple analytical function and adaptive mesh refinement is used to control mesh quality near the cylinder.

The plot shows the evolution of the 3 boundary layers with time, according to the transient solution of the Navier-Stokes equations for the Rotating Disk Flow problem (see Schlichting Boundary Layer Theory)

In this test case, the numerical solution of a sessile drop is compared to the exact solution given by a set of ordinary equations for a 3D axisymmetric drop, both compared during the last 2 seconds of this animation. The test consists in releasing a drop and, due to gravitational force, the drop approaches the wall...

3-dimensional vortex field test case. This particular benchmark tests extensively the remeshing methodology implemented in our CFD code. The test consists in applying a 3d vortex field on a sphere which will be complete distorted in t=0.5T, where T is the total time of the simulation. From t=0.5T to t=T, the vortex...

In this test case, the remeshing methodology is massively tested while the bubble is subjected to a single vortex field. The tetrahedral background mesh is colored by the magnitude of the vortex field velocity. The red color represents high velocity, while the blue one stands for low intensity. As can be seen, the...

The Zalesak's test case is a common benchmark to evaluate the reconstruction of the interface while the Zalesak sphere is rotating. The background flow is imposed with no need of solving the Navier-Stokes equations. As can be seen in the animation and despite the coarse mesh used on this test case, our moving mesh...

Modeling of last stage of two bubble's coalescence process. The animation shows three different views of the same simulation to illustrate the approaching of two bubbles. Using the 3D ALE-FEM code, we are able to study the physical phenomena that takes place before the unexplored and non-trivial process of bubble...

Two-phase flow of a single bubble in a triangular channel. The Navier-Stokes equations are discretized through the Arbitrary Lagrangian-Eulerian framework in which the interface between fluids are accessed sharply by defining a triangular surface embed on the tetrahedral mesh. In such a particular simulation, the...

Gravity-driven flow of an air bubble in sugar-syrup solution. The result was compared to the White and Beardmore flow pattern map (1962) and good agreement was found for the rising velocity of the air bubble and the liquid film thickness.

Gravity-driven flow of an air bubble in sucrose solution. The result was compared to the White and Beardmore flow pattern map (1962) and good agreement was found for the rising velocity of the air bubble and liquid film thickness.

Gravity-driven flow of an air bubble in sucrose solution. The result was compared to the White and Beardmore flow pattern map (1962) and good agreement was found for the rising velocity of the air bubble and liquid film thickness.

Heat and Mass transfer of refrigerant R1234ze in square cross-section microchannels with a constant heat flux applied on the bottom of the domain. Red color represent high temperature and blue stands for low temperature.

Two-phase slug flow in square cross-section microchannels. 3D Finite Element simulation was successfully carried out to predict bubble shape, velocity, liquid slug and liquid film thickness in the scope of the CMOSAIC project financed by NanoTera in Switzerland. The liquid and gas phases correspond to the refrigerant...

Gravity-driven flow of an air bubble in sugar-syrup solution. The 3D equations were discretized using the ALE framework and the Finite Element Method. The numerical result was compared to the White and Beardmore flow pattern map (1962) and good agreement was found for the rising velocity. Bubble shape and liquid film...

2D simulation of a rising bubble with heat transfer. The bubble, lighter then the surrounding fluid, rises and moves towards the heat interface (green color) . The non-dimensional numbers used in this simulations were Re = 200, Sc = 1000, We = 10, mu_in = 0.5, mu_out = 1.0, rho_out = 1.0, rho_in = 0.01. On the right...

Rising of a single bubble immersed in a fluid where the bottom part (red) is heated and has temperature higher then the upper part (blue). The bubble is then release and due to buoyancy effect, it crosses the heat transition line (green color). The heat transfer process takes place into the bubble dynamic and due to...

The interface between fluids is represented by a set of points, edges and facets. These facets are triangles which are part of the tetrahedron mesh. Each triangle represents the shared facet of two adjacent tetrahedrons. As can be seen, while the surface movies with respect to the flow, the elements are compressed...

The interface between fluids is represented by a set of points, edges and facets. These facets are triangles which are part of the tetrahedron mesh. Each triangle represents the shared facet of two adjacent tetrahedrons. As can be seen, while the surface movies with respect to the flow, the elements are stretched...

The rising of a single air bubble in a stagnant column of water has been simulated. The 3-dimensional two-phase flow phenomena can be numerically predicted. At the leftmost frame, the interface between fluid is represented by a set of points, edges and triangular facets which are part of the tetrahedron domain mesh...

Numerical simulation of 2D microchannel two-phase flow. The equations are written in the Arbitrary Lagrangian-Eulerian framework (ALE) through the Finite Element method (FEM), ANJOS et al. (2013). The bubble velocity profile is shown on the top of the figure where the highest horizontal speed is represented by the red...

Numerical simulation of 3-dimensional two-phase flow is performed to predict the rising of an air bubble in a initially stagnant water-sugar solution. At the leftmost frame, the interface between fluid is represented by a set of points, edges and triangular facets which are part of the tetrahedron domain mesh. The...