FEM vs. FVM

Ed Fontes November 29, 2018

There has always been a debate among engineers working with fluid flow about the suitability of finite element methods for CFD. Some engineers have a firm opinion about the superiority of finite volume methods compared to finite element methods. Is there a scientific support for this opinion? No, not in general. Different methods may be suitable for different problems. Let us see why.

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Ed Fontes June 6, 2018

The Adidas® Telstar® soccer ball is the official ball of the 2018 FIFA World Cup™, and the Nike® Ordem V soccer ball is used in the seven largest national leagues in Europe, including the top three: the Spanish La Liga, the English Premier League, and the Italian Serie A. Previously, we discussed an experimental setup for measuring the terminal velocity of these two soccer balls to see if there’s a difference that could affect player performance. Here’s what we found…

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Ed Fontes June 1, 2018

Every four years, people interested in association football/soccer (a few billion people) talk about the FIFA World Cup™. We at COMSOL are no exception. During coffee breaks and lunches, we are discussing the different teams, players, preparations, and the tiny details that might impact the teams. The ball is an important protagonist of the games. The subject of the ball combines our passion for soccer and physics into one discussion!

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Ed Fontes May 31, 2018

In a previous blog post, we discussed using field-based methods (level set and phase field) for modeling free surfaces. Another option, moving mesh, can handle free liquid surfaces that do not undergo topology changes. In this blog post, we will demonstrate how to use the moving mesh method for modeling free surfaces and compare the results with field-based methods.

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Ed Fontes May 15, 2018

There are four methods for modeling free liquid surfaces in the COMSOL Multiphysics® software: level set, phase field, moving mesh, and stationary free surface. In the first part of this blog series, we discuss the level set and phase field methods, which are field-based methods that describe almost any type of free liquid surface. In part two, we will compare the results from this post with those obtained using the Moving Mesh interface for solving free surface problems.

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Ed Fontes March 26, 2018

The algebraic multigrid (AMG) solver provides robust solutions for large CFD simulations. Available as of version 5.3a of the COMSOL Multiphysics® software, the AMG method only requires one mesh, in contrast to the geometric multigrid (GMG) solver, which requires at least one extra coarser mesh. This eliminates the hassle associated with creating coarse meshes for complex geometries with small details that are difficult to mesh unless a fine mesh is used.

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Ed Fontes December 26, 2017

You can easily describe composition- and temperature-dependent fluid properties using the thermodynamic properties database, available as of version 5.3a of the COMSOL Multiphysics® software. For reacting systems, the database computes enthalpy of formation and enthalpy of reaction. For fluid flow and heat and mass transfer, the database can compute viscosity, density, heat capacity, thermal conductivity, and diffusivity of liquids and gases. For systems with several phases, the thermodynamic properties database computes the composition of the phases at equilibrium.

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Ed Fontes June 26, 2017

Wall-bounded turbulent flows display extreme gradient close to the walls. The most accurate way to treat these gradients is to resolve them using a low Reynolds number model, which is computationally expensive. Industrial applications use wall functions, which model the flow closest to the wall rather than resolving it. Wall functions are robust and efficient, but not particularly accurate. New automatic wall treatment functionality in the COMSOL® software combines the benefits of wall functions and the low Reynolds number model.

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Ed Fontes May 15, 2017

Accurately modeling turbulent flow is always a challenge with turbulence models, since they inherently involve simplifications. In addition, accurate models tend to add equations that don’t help the convergence of the already highly nonlinear models. To solve this problem, version 5.3 of the COMSOL Multiphysics® software introduces the v2-f turbulence model. It combines the accuracy obtained with models that describe the anisotropy of the turbulent boundary layers with the robustness of two-equation turbulence models.

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Ed Fontes February 2, 2017

Fat-washing cocktails has become popular in the last decade. This technique has made it possible for bartenders to create drinks such as the Benton’s Old-Fashioned, a bacon-infused bourbon cocktail, and a milder pecan-butter-infused bourbon. In this blog post, we discuss this innovative cocktail technique and how it can be transferred to an industrial scale. In fact, many chemical processes in a variety of industries already use similar methods.

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Ed Fontes December 23, 2016

Natural convection is a phenomenon found in many science and engineering applications, such as electronics cooling, indoor climate systems, and environmental transport problems. The CFD and Heat Transfer modules in version 5.2a of the COMSOL Multiphysics® software include functionality that makes it easier to set up and solve natural convection problems. In this blog post, we give an overview of natural convection, the new functionality, and some of the difficulties that we may stumble upon when modeling natural convection.

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