Creating Geometries News

What is a geometry database?

The starting point to conducting CFD simulations is to have a representative geometric model of the installation to be considered. Whether you import the geometry from files previously generated in CAD software or build the geometry in CASD, it will be stored in a geometry database for FLACS. A geometry database is an organised collection of all information about the considered geometry…

Working with a geometry database

Some installations, especially old ones, do not have any existing geometric (CAD) model in digital format. To be able to conduct CFD modelling for such installations you need to generate a representative geometric model. The most common way to create a new geometry is to build it manually based on all the information available, such as general layouts, drawings and…

How to define materials in a geometry

Materials in CASD are used to differentiate objects according to their type or their discipline. The different materials will have different colours which can be defined by the user. For a general description of the geometry database and how to work with it, please refer to the article What is a geometry database? and Working with a geometry database, respectively. Define a new…

How to build an assembly

An assembly is a group of instances of objects in a geometry. In a complicated geometry, assemblies are very useful for organizing the numerous objects in disciplines, zones etc. All geometries have at least one assembly, called the top assembly. If you are not familiar with geometry databases please read the article on Working with a geometry database. Add an Assembly To…

How to define a grating

Porous objects such as grated decks and walls are commonly encountered in facilities. In addition, porous volumes may be used to represent partially open/closed objects such as heat exchangers. For a general introduction to working with a geometry database and define new objects please read the article on Working with a geometry database. Define a grating in CASD To define a primitive to…

How to calculate porosities

The Flacs solver is based on the porosity/distributed resistance (PDR) approach. In this approach, obstructions in the flow field are represented by a three-dimensional field (porosity) that measures whether space is open to the flow (porosity = 1), partially blocked (0 < porosity < 1), or completely blocked (porosity = 0). The porosities have to be computed before a Flacs simulation can

How to import a geometry

Many installations have 3D geometric models in file formats which can be directly used in FLACS. These existing CAD files can be imported into FLACS in two different ways: the first way is to import directly in CASD; the second way uses a command-line utility called geo2flacs. In this article we will discuss both methods, and list the geometry file formats…

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