Sergio Rodolfo Idelsohn

• Ph.D
• Professor at Catalan Institution for Research and Advanced Studies

We present a fast first order explicit time integration scheme for solving parabolic problems in mechanics via standard numerical methods in space using irregular grids, such as unstructured finite element meshes, or grids containing elements or cells of very different sizes. The new scheme extends one of the explicit FIC-Time (EFT) integration met...

The pseudo-direct numerical simulation (P-DNS) method is a recently developed multiscale strategy designed for high-fidelity computational simulation of complex flow physics. This physics-based data-driven approach involves numerically solving both the fine and global scales. The former is precomputed into representative volume elements (RVEs), who...

Efficiently simulating turbulent fluid flow within a boundary layer is one of the major challenges in fluid mechanics. While skin friction may have a limited impact on drag at high Reynolds numbers, it plays a crucial role in determining the location of fluid separation points. Shifts in these separation points can dramatically alter drag and lift,...

We present a family of fast explicit time integration schemes of first, second and third order accuracy for parabolic problems in mechanics solved via standard numerical methods that have considerable higher computational efficiency versus existing explicit methods of the same order. The derivation of the new explicit schemes is inspired on the fin...

An overview of the Pseudo-Direct Numerical Simulation (P-DNS) method is presented. This is a multi-scale method aiming at numerically solving the unknown fields at two different scales, namely coarse and fine. The P-DNS method is built around four key ideas. The first one is that of numerically solving both scales, which facilitates obtaining solut...

The multiscale method called Pseudo-Direct Numerical Simulation (P-DNS) is presented as a Reduced Order Model (ROM) aiming to solve problems obtaining similar accuracy to a solution with many degrees of freedom (DOF). The theoretical basis of P-DNS is other than any standard ROM. However, from a methodological point of view, P-DNS shares the idea o...

It is well known that the inherent three‐dimensional and unsteady nature of turbulent flows is a stumbling block for all approaches aimed at resolving their spatial and temporal variability. The Pseudo‐Direct Numerical Simulation (P‐DNS) method for turbulent flows, proposed by the authors in a previous publication, focused on resolving the spatial...

The external and internal airflow and air renewal inside urban buses have taken especial relevance since the COVID-2 pandemic. Computational fluid dynamics (CFD) simulations, which focus on the estimation of indoor airflow are not conclusive about the impact of using Heat, Ventilation and Air Conditioning (HVAC) systems on diseases’ transmission ri...

The methodology previously proposed by the authors to solve particle-laden turbulent flows through a multiscale approach is extended by introducing a continuous function for the dispersed phase concentration. The proposed continuous model is especially useful for studying the motion of particle streams in which gravitational and inertial effects ca...

We present an overview of the Pseudo-Direct Numerical Simulation (P-DNS in short) method for the solution of multi-scale phenomena. The method can be seen as an adaptation of the variational multi-scale (VMS) method, where the fine solution is solved numerically instead of analytically. Also, from the point of view of homogenization methods it can...

A multiscale approach for the detailed simulation of water droplets dispersed in a turbulent airflow is presented. The multiscale procedure combines a novel representative volume element (RVE) with the Pseudo Direct Numerical Simulation (P-DNS) method. The solution at the coarse-scale relies on a synthetic model, constructed using precomputed offli...

Accepting as a premise that the solution of a Direct Numerical Simulation (DNS) is a reliable result, Pseudo-DNS (P-DNS) is a multi-scale method where both the coarse and the fine scales are solved numerically[1]. The most expensive part of the computations, the solution of the fine-scale, is performed offline where its results, stress tensors at e...

In this work, a new model for the analysis of incompressible fluid flows with massive instabilities at different scales is presented. It relies on resolving all the instabilities at all scales without any additional model, i.e., following the direct numerical simulation style. Nevertheless, the computation is carried out at two levels or scales, te...

Abstract In this paper we present a collection of techniques used to formulate a projection-based reduced order model (ROM) for zero Mach limit thermally coupled Navier–Stokes equations. The formulation derives from a standard proper orthogonal decomposition model reduction, and includes modifications to improve the drawbacks caused by the inherent...

This work presents a novel proposal of a second-order accurate (in time and space) particle-based method for solving transport equations including incompressible flows problems within a mixed Lagrangian-Eulerian formulation. This methodology consists of a symmetrical operator splitting, the use of high-order operators to transfer data between the p...

The tendency of the polymers to melt and drip when they are exposed to external heat source play a very important role in the ignition and the spread of fire. Numerical simulation is a promising methodology for predicting this behaviour. In this paper, a computational procedure that aims at analyzing the combustion, melting and flame spread of poly...

Highly concentrated moving nonlinearities are extremely difficult to solve numerically. The Selective Laser Melting Additive Manufacturing process is a problem of this kind. A material global-local scheme is proposed, which consists in describing the neighbourhood of the heat source by a moving local domain while the material phase fractions are re...

This chapter presents an overview of some computational methods for the analysis of problems in ship hydrodynamics. Attention is focused on the description of stabilized finite element formulations derived via a finite increment calculus (FIC) procedure. Both arbitrary Lagrangian–Eulerian (ALE) and fully Lagrangian forms are presented. Details of t...

Particle methods in computational fluid dynamics (CFD) are numerical tools for the solution of the equations of fluid dynamics, obtained by replacing the fluid continuum with a finite set of particles. One of the key attributes of particle methods is that pure advection is treated exactly. The convection of properties eases the solution of multi‐ma...

In a previous paper the authors present an elemental enriched space to be used in a finite element framework (EFEM) capable to reproduce kinks and jumps in an unknown function using a fixed mesh in which the jumps and kinks do not coincide with the inter-element boundaries. In this previous publication, only scalar transport problems where solved (...

This is part of an article series on a variational framework for continuum mechanics based on the Finite Increment Calculus (FIC). The formulation utilizes high order derivatives of the classical fields of continuum mechanics integrated over control regions to construct stabilizing modification terms. Fields may include displacements, body forces,...

The latest version of the Particle Finite Element Method (PFEM-2) [1] is a numerical method based on the Lagrangian formulation of the equations which presents advantages in terms of robustness and efficiency over classical Eulerian methodologies especially when convection plays an important role [2]. Previous publications demonstrated its ability...

Problems characterised by steep moving gradients are challenging for any numerical technique and even more for the successful formulation of Reduced Order Models (ROMs). The aim of this work is to study the numerical solution of problems with steep moving gradients, by placing the focus on parabolic problems with highly concentrated moving sources....

An a-posteriori error estimate with application to inviscid compressible flow problems is presented. The estimate is a surrogate measure of the discretization error, obtained from an approximation to the truncation terms of the governing equations. This approximation is calculated from the discrete nodal differential residuals using a reconstructed...

Purpose The purpose of this paper is to propose a new elemental enrichment technique in order to improve the accuracy of the simulations of thermal problems containing weak discontinuities. Design/methodology/approach The enrichment is introduced in the elements cut by the materials interface by means of adding additional shape functions. The we...

Fast and accurate Lagrangian finite element model for solving Navier-Stokes equations

The main goal of this paper is to validate experimentally the principal conclusions previuosly published in [?]. Two manufactured test cases were considered with their respective analytic solutions. First, an scalar transport equation is taken written in such a way that several parameters are included to stress the limits where the Eulerian and the...

We propose here a displacement-based updated Lagrangian fluid model developed to facilitate a monolithic coupling with a wide range of structural elements described in terms of displacements. The novelty of the model consists in the use of the explicit streamline integration for predicting the end-of-step configuration of the fluid domain. It is sh...

Inhomogeneous essential boundary conditions must be carefully treated in the formulation of Reduced Order Models (ROMs) for non-linear problems. In order to investigate this issue, two methods are analysed: one in which the boundary conditions are imposed in an strong way, and a second one in which a weak imposition of boundary conditions is made....

Discretization processes leading to numerical schemes sometimes produce undesirable effects. One potentially serious problem is that a discretization may produce the loss of validity of some of the physical principles or mathematical properties originally present in the continuous equation. Such loss may lead to uncertain results such as numerical...

The purpose of this paper is to propose a new elemental enrichment technique in order to improve the accuracy of the simulations of thermal problems containing weak discontinuities. The enrichment is introduced in the elements cut by the materials interface by means of adding additional shape functions. The weak form of the problem is obtained usin...

The main goal of this paper is to validate experimentally the principal conclusions previously published in [17]. Two manufactured test cases were considered with their respective analytic solutions. First, a scalar transport equation is considered written in such a way that several parameters are included to stress the limiting situation where the...

The latest generation of the particle finite element method (PFEM-2) is a numerical method based on the Lagrangian formulation of the equations, which presents advantages in terms of robustness and efficiency over classical Eulerian methodologies when certain kind of flows are simulated, especially those where convection plays an important role. Th...

This paper presents a finite element that incorporate weak, strong and both weak plus strong discontinuities with linear interpolations of the unknown jumps for the modeling of internal interfaces. The new enriched space is built by subdividing each triangular or tetrahedral element in several standard linear sub-elements. The new degrees of freedo...

We present an approach for the simulation of landslides using the Particle Finite Element Method of the second generation. In this work, the multiphase nature (granular phase and water) of the phenomenon is considered in a staggered fashion using a single, indeformable Finite Element mesh. A fractional step and a monolithic strategy are used for th...

In previous works [S. R. Idelsohn, J. Marti, P. Becker, E. O nate, Analysis of multifluid flows with large time steps using the particle

A Navier-Stokes solver based on Cartesian structured finite volume discretization with embedded bodies is presented. Fluid structure interaction with solid bodies is performed with an explicit partitioned strategy. The Navier-Stokes equations are solved in the whole domain via a Semi-Implicit Method for Pressure Linked Equations (SIMPLE) using a co...

Trends in Computational Mechanics that may have Future.

En este trabajo se propone una alternativa para la matriz de pre-condicionamiento a emplear en el metoda de gradientes conjugados, apli cado a la soluci6n por elementos finitos/minimos cuadrados de la ecua-cion potencial transonica. La alternativa propuesta permite reducir, finalmente, el esquema de gradientes conjugados con precondicionamiento a u...

Palabras clave: Modelos de Orden Reducido, POD, Métodos Multiescala Resumen. En este trabajo se presentan las subescalas de orden reducido para métodos de descomposición ortogonal apropiada (POD). La idea básica consiste en separar la solución de alta fidelidad en dos partes: la parte que puede ser capturada por el modelo reducido y la parte que no...

Water management is one of the key factors in Proton Exchange Fuel Cell (PEFC) performance. The water produced within the fuel cell is evacuated through the gas channels, but at high current densities water can block the channel, thus limiting the current density generated in the fuel cell. A semi-analytical model of a water droplet emerging from a...

A reduced-order model for an efficient analysis of cardiovascular hemodynamics problems using multiscale approach is presented in this work. Starting from a patient-specific computational mesh obtained by medical imaging techniques, an analysis methodology based on a two-step automatic procedure is proposed. First a coupled 1D-3D Finite Element Sim...

The latest version of the Particle-Finite Element Method (PFEM), which incorporates the novel explicit integration strategy named eXplicit Integration of Velocity and Acceleration following Streamlines (X-IVAS), has proven to be fast and accurate to solve homogeneous flows, mainly thanks to the possibility of using large time-steps. In this work th...

The latest version of the Particle-Finite Element Method (PFEM), which incorporates the novel explicit integration strategy named eXplicit Integration of Velocity and Acceleration following Streamlines (X-IVAS), has proven to be fast and accurate to solve homogeneous flows, mainly thanks to the possibility of using large time-steps. In this work th...

Multifluids are those fluids in which their physical properties (viscosity or density) vary internally and abruptly forming internal interfaces that introduce a large nonlinearity in the Navier–Stokes equations. For this reason, standard numerical methods require very small time steps in order to solve accurately the internal interface position. In...

The simulation of engineering problems is quite often a complex task that can be time consuming. In this context, the use of Hyper Reduced Order Models (HROMs) is a promising alternative for real-time simulations. In this work, we study the design of HROMs for non-linear problems with a moving source. Applications to nonlinear phase change problems...

An experimental and numerical investigation of the effect of bisphenol A bis(diphenyl phosphate) (BDP) and polytetrafluoroethylene (PTFE) on the fire behaviour of bisphenol A polycarbonate/acrylonitrile butadiene styrene (PC/ABS) in the vertical UL 94 scenario is presented. Four PC/ABS blends were discussed, which satisfy different UL 94 classifica...

This paper describes a strategy to solve multi-fluid and fluid-structure interaction (FSI) problems using Lagrangian particles combined with a fixed finite element (FE) mesh. Our approach is an extension of the fluid-only PFEM-2 (Idelsohn et al., Eng Comput 30(2):2-2, 2013; Idelsohn et al., J Numer Methods Fluids, 2014) which uses explicit integrat...

In this chapter we present some Reduced-Order Modelling methods we have developed for the stabilized incompressible Navier-Stokes equations. In the first part of the chapter, we depart from the stabilized finite element approximation of incompressible flow equations and we build an explicit proper-orthogonal decomposition based reduced-order model....

This paper presents a state of the art in the Particle Finite Element Method, normally called PFEM, its emphasis in the new ideas oriented to extend its application not only to solve fluid structure interaction and multifluid problems, also bring new opportunities to shorten the gap between engineering design times and computational simulation time...

Two-fluid modeling of the casting process is important as it particularly provides insight to the air behavior during the filling process. Large deformations of the material-air front require an interface capturing technique to detect it on the fixed Eulerian meshes. On the other hand, if sharp interface is considered, jumps in the material propert...

This paper presents a high performance implementation for the particle-mesh based method called particle finite element method two (PFEM-2). It consists of a material derivative based formulation of the equations with a hybrid spatial discretization which uses an Eulerian mesh and Lagrangian particles. The main aim of PFEM-2 is to solve transport e...

In this work, the finite point method is applied to the solution of high-Reynolds compressible viscous flows. The aim is to explore this important field of applications focusing on two main aspects: the easiness and automation of the meshless discretization of viscous layers and the construction of a robust numerical approximation in the highly str...

This article (author's post-print) is available at my website: http://nadukandi.es/publications.html We present a 3-noded triangle and a 4-noded tetrahedra with a continuous linear velocity and a discontinuous linear pressure field formed by the sum of an unknown constant pressure field and a prescribed linear field that satisfies the steady state...

A comparative assessment of the Finite Point Method (FPM) is presented. Using a wing-fuselage configuration under transonic inviscid flow conditions as reference test case, the performance of the FPM flow solver is compared with an equivalent edge-based Finite Element (FEM) implementation. Efficiency issues have discouraged practical application of...

In this work the Reduced-Order Subscales for Proper Orthogonal Decomposition models are pre-sented. The basic idea consists in splitting the full-order solution into the part which can be captured by the reduced-order model and the part which cannot, the subscales, for which a model is required. The proposed model for the subscales is defined as a...

In this work, a domain decomposition strategy for non-linear hyper-reduced-order models is presented. The basic idea consists of restricting the reduced-order basis functions to the nodes belonging to each of the subdomains into which the physical domain is partitioned. An extension of the proposed domain decomposition strategy to a hybrid full-ord...

SUMMARYA finite point method for solving compressible flow problems involving moving boundaries and adaptivity is presented. The numerical methodology is based on an upwind‐biased discretization of the Euler equations, written in arbitrary Lagrangian–Eulerian form and integrated in time by means of a dual‐time steeping technique. In order to exploi...

In this paper, we present an explicit formulation for reduced‐order models of the stabilized finite element approximation of the incompressible Navier–Stokes equations. The basic idea is to build a reduced‐order model based on a proper orthogonal decomposition and a Galerkin projection and treat all the terms in an explicit way in the time integrat...

The rise of GPUs in modern high-performance systems increases the interest in porting portion of codes to such hardware. The current paper aims to explore the performance of a portable state-of-the-art FE solver on GPU accelerators. Performance evaluation is done by comparing with an existing highly-optimized OpenMP version of the solver. Code port...

Creating a highly parallelizable code is a challenge specially for Distributed Memory Machines (DMMs). Moreover, algorithms and data structures suitable for these platforms can be very different from the ones used in serial code. For this reason, many programmers in the field prefer to start their own code from scratch. However, for an already exis...

In the present work an implementation of the Back and Forth Error Compensation and Correction (BFECC) algorithm specially suited for running on General-Purpose Graphics Processing Units (GPGPUs) through Nvidia’s Compute Unified Device Architecture (CUDA) is analyzed in order to solve transient pure advection equations. The objective is to compare i...

A fully Lagrangian compressible numerical framework for the simulation of underwater implosion of a large air bubble is presented. Both air and water are considered compressible and the equations for the Lagrangian shock hydrodynamics are stabilized via a variationally consistent multiscale method. A nodally perfect matched definition of the interf...

Purpose ‐ The purpose of this paper is to highlight the possibilities of a novel Lagrangian formulation in dealing with the solution of the incompressible Navier-Stokes equations with very large time steps. Design/methodology/approach ‐ The design of the paper is based on introducing the origin of this novel numerical method, originally inspired on...

We propose a fully Lagrangian monolithic system for the simulation of the underwater implosion of cylindrical aluminum containers. A variationally stabilized form of the Lagrangian shock hydrodynamics is exploited to deal with the ultrahigh compression shock waves that travel in both air and water domains. The aluminum cylinder, which separates the...

A computational procedure for analysis of the melting, burning and flame spread of polymers under fire conditions is presented. The method, termed particle finite element method (PFEM), combines concepts from particle-based techniques with those of the standard finite element method (FEM). The key feature of the PFEM is the use of an updated Lagran...

We present some developments in the Particle Finite Element Method (PFEM) for the solution of complex coupled problems in marine, naval and harbour engineering involving fluid-soil-structure interaction (FSSI). The PFEM uses an updated Lagrangian description to model the motion of nodes (particles) in a continuum domain containing fluid, soil/rock...

This paper aims to present a coupled solution strategy for the problem of seepage through a rockfill dam taking into account the free-surface flow within the solid as well as in its vicinity. A combination of a Lagrangian model for the structural behavior and an Eulerian approach for the fluid is used. The particle finite element method is adopted...

In this paper, we present a computational algorithm for solving an important practical problem, namely, the thermoplastic polymer melting under fire conditions. We propose here a technique that aims at minimizing the computational cost. This is basically achieved by using the immersed boundary‐like approach, combining the particle finite element me...

Particle Finite Element Method-Second generation (PFEM-2) is a method characterized by using both particles and mesh to solve physics equations. In some previous papers the mathematical and numerical basis of the method with also some results were presented showing a good accuracy and high performance for solving scalar-transport and momentum-trans...

In this work, a new enrichment space to accommodate jumps in the pressure field at immersed interfaces in finite element formulations, is proposed. The new enrichment adds two degrees of freedom per element that can be eliminated by means of static condensation. The new space is tested and compared with the classical P1 space and to the space propo...

Este trabajo presenta un nuevo método de integración temporal puramente explícito que es estable para grandes pasos de tiempo. El mismo no requiere inversión de matrices ni resolución de un sistema de ecuaciones y por lo tanto es apto para ser paralelizado fácilmente y con alta eficiencia. En este primer trabajo se aplicará la teoría propuesta para...

Over the last twenty years, computer simulation of incompressible fluid flow has been based on the Eulerian formulation of the fluid mechanics equations on continuous domains. However, it is still difficult to analyze problems in which the shape of the free surfaces or internal interfaces changes continuously or in fluid-structure interactions wher...

We propose a technique for improving mass‐conservation features of fractional step schemes applied to incompressible flows. The method is illustrated by using a Lagrangian fluid formulation, where the mass loss effects are particularly apparent. However, the methodology is general and could be used for fixed grid approaches. The idea consists in re...

Negatively buoyant jets consist in a dense fluid injected vertically upward into a lighter ambient fluid. The numerical simulation of this kind of buoyancy-driven flows is challenging as it involves multiple fluids with different physical properties. In the case of immiscible fluids, it requires, in addition, to track the motion of the interface be...

We present a general formulation for analysis of fluid-structure interaction problems using the particle finite element method (PFEM). The key feature of the PFEM is the use of a Lagrangian description to model the motion of nodes (particles) in both the fluid and the structure domains. Nodes are thus viewed as particles which can freely move and e...

An explicit time integrator without the CFL < 1 restriction for the momentum equation is presented. This allows stable large time-steps in problems dominated by convection, independently of the spatial discretization.The idea is to use the information existing at time t=tnt=tn in the velocity streamlines as well as in the acceleration streamlines t...

The solution of problems in computational fluid dynamics (CFD) represents a classical field for the application of advanced numerical methods. Many different approaches were developed over the years to address CFD applications. Good examples are finite volumes, finite differences (FD), and finite elements (FE) but also newer approaches such as the...

We present a general formulation for the analysis of fluid-structure interaction problems using the particle finite element method (PFEM). The key feature of the PFEM is the use of a Lagrangian description to model the motion of nodes (particles) in both the fluid and the structure domains. Nodes are thus viewed as particles which can freely move a...

Graphic processing units have received much attention in last years. Compute-intensive algorithms operating on multidimensional arrays that have nearest neighbor dependency and/or exploit data locality can achieve massive speedups. Simulation of problems modeled by time-dependent Partial Differential Equations by using explicit time-stepping method...

An increasing interest is rising on the study of rockfill embankment dams during overspilling. Design criteria of earth dams are being reviewed in many countries to guarantee an increasing safety level in front of an exceptional flooding. The possibility of studying the failure process is currently limited by the lack of a precise knowledge and by...

Resumen La interacción de los fluidos con las estructuras de su entorno es un desafío clásico para las técnicas numéricas. El objetivo de este trabajo es doble: en primer lugar se proporciona una explicación teórica simple de los principales problemas que se deben superar cuando se trata con un fluido incompresible. A continuación se introduce y ju...

In this work, we extend the Particle Finite Element Method (PFEM) to multi-fluid flow problems with the aim of exploiting the fact that Lagrangian methods are specially well suited for tracking interfaces. We develop a numerical scheme able to deal with large jumps in the physical properties, included surface tension, and able to accurately represe...

An adaptive Finite Point Method (FPM) for solving shallow water problems is presented. The numerical methodology we propose, which is based on weighted-least squares approximations on clouds of points, adopts an upwind-biased discretization for dealing with the convective terms in the governing equations. The viscous and source terms are discretize...

We present some developments in the particle finite element method (PFEM) for analysis of complex coupled problems in mechanics involving fluid–soil–structure interaction (FSSI). The PFEM uses an updated Lagrangian description to model the motion of nodes (particles) in both the fluid and the solid domains (the later including soil/rock and structu...

We present a stabilized numerical formulation for incompressible continua based on a higher-order Finite Calculus (FIC) approach and the finite element method. The focus of the paper is on the derivation of a stabilized form for the mass balance (incompressibility) equation. The simpler form of the momentum equations neglecting the non-linear conve...

This paper presents the Particle Finite Element Method (PFEM) and its application to multi-fluid flows. Key features of the method are the use of a Lagrangian description to model the motion of the fluid particles (nodes) and that all the information is associated to the particles. A mesh connects the nodes defining the discretized domain where the...

We present some developments in the formulation of the Particle Finite Element Method (PFEM) for analysis of complex coupled problems on fluid and solid mechanics in engineering accounting for fluid-structure interaction and coupled thermal effects, material degradation and surface wear. The PFEM uses an updated Lagrangian description to model the...

This article (author's post-print) is available at my website: http://nadukandi.es/publications.html We present a collection of stabilized finite element (FE) methods derived via first- and second-order finite calculus (FIC) procedures. It is shown that several well known existing stabilized FE methods such as the penalty technique, the Galerkin L...

RESUMEN Este trabajo presenta por un lado una breve síntesis de algunas importantes contribuciones dirigida a la unificación de códigos computacionales para flujos tanto compresible como incompresible y por otro un eficiente precondicionador local para todo el rango de números de Mach y Reynolds implementado sobre un esquema iterativo tipo GMRES co...

RESUMEN Presentamos un método de paneles para el cómputo linealizado del flujo potencial con una superficie libre, y el de la curva de resistencia de olas sobre un cuerpo con formas hidronavales en función del número de Fi-oude. Las ecuaciones gobernantes del flujo potencial con una superficie libre son, la ecuación de Laplace para el potencial de...

Current work presents a monolithic method for the solution of fluid–structure interaction problems involving flexible structures and free-surface flows. The technique presented is based upon the utilization of a Lagrangian description for both the fluid and the structure. A linear displacement–pressure interpolation pair is used for the fluid where...

We present advances in the Particle Finite Element Method (PFEM) for solving multidisciplinary problems in fluid and solid mechanics accounting for fluid-structure interaction (FSI), thermal coupling and free surface effects. The PFEM uses an updated Lagrangian description to follow the motion of nodes (particles) in the fluid and the structure dom...

Heterogeneous incompressible fluid flows with jumps in the viscous properties are solved with the particle finite element method using continuous and discontinuous pressure fields. We show the importance of using discontinuous pressure fields to avoid errors in the incompressibility condition near the interface. KeywordsHeterogeneous fluids-Multi-...

In this paper we investigate experimentally the injection of a negatively buoyant jet into a homogenous immiscible ambient fluid. Experiments are carried out by injecting a jet of dyed fresh water through a nozzle in the base of a cylindrical tank containing rapeseed oil. The fountain inlet flow rate and nozzle diameter were varied to cover a wide...