Tips & Tricks

Automatic covering of larger unwanted holes in CFD-VisCART

CFD-VisCART meshing automatically closes or covers holes in the geometry that are smaller in size than the cell size specified at the surfaces. To cover LARGER holes, the ‘Max Hole Size to Cover’ feature can be used. This feature, introduced in V2013.2, works to automatically cover larger holes in the geometry during mesh generation, and thus prevents the mesh from leaking into unwanted regions. This feature is available with all mesh types supported in CFD-VisCART.

Parallel processing

“To pull a bigger wagon, it is easier to add more horses than to grow a gigantic horse.” This paraphrased quotation nicely expresses the basic concept of parallel processing. The speed of sequential computers has been doubling every eighteen months, according to Moore’s law. However, at any given time, that speed is limited by the state of the art in integrated circuit design and manufacturing. To circumvent that limitation, it is possible to split a given computationally intensive task among multiple processors working simultaneously.

The manufacturing of sand cores

The manufacturing of iron, steel and non-ferrous castings is achieved using a variety of casting process designs, and most of these involve the use of sand cores which form the internal shape of the casting. A good quality casting requires a good quality core. Dimensional stability, uniform density, strength, hardness and permeability are some of the characteristics that need to be controlled. A good core must have suffi cient strength and hardness to be handled and to resist during the pouring of liquid metal. Suffi cient permeability is also necessary for the escape of gases generated during the casting process. The diff erent manufacturing processes and some of the issues related to core production will be discussed here.

FLEXlm protection file system

ESI group needs to license, manage and track a variety of licensing options, platform and product dependencies. FLEXlm is one of the only software that is up to this task. A simple, shrinkwrapped license management product would not be powerful and flexible enough to license all ESI products.

Why it is useful to describe problems in terms of non-dimensional parameters and which ones are the main important in solidification?

A dimensionless quantity is a quantity without any physical units. Such a number is typically defi ned as a product or ratio of quantities which do have units, in such a way that all units cancel. Dimensionless quantities are widely used in the fields of physics and engineering but also in every day life.

Grouping parts during data import in CFD-VisCART

When dealing with complex industrial models such as cars and airplanes, hundreds of parts need to be managed. Each one of these parts may also be subdivided into different components. In order to easily manipulate these different parts and components in CFD-VisCART, you can make use of the grouping feature.

CFD-VisCART: Mesh Extrusion

In most CFD simulations, it is required to place inlets/outlets far enough from the region of interest in order to reduce their influence on the solution. In many applications, this can be done by extruding existing inlets/outlets BC patches away from the domain.

Preserving boundaries between patches with CFD-VisCART’s Single Domain mesher

The ‘Preserve Features’ option does very well in preserving features between geometry patches – as long as the patches are not coplanar (dihedral angle = 0) or include a very small dihedral angle between them.

CFD-VisCART: Suppression of parts for mesh generation

When performing an analysis comparing component A versus component B, it is useful to have both components stored in the same file for physical comparison and documentation purposes. However, when generating the mesh for the analysis, only one of the parts should be considered at a time. The "Suppress" option in CFD-VisCART makes this possible.

Boundary Layer meshing in CFD-VisCART

In order to accurately capture flow field characteristics, a fine mesh near boundary walls is often needed. This is commonly referred to as the Boundary Layer mesh or simply, Boundary Layers. When dealing with structured meshes, one would cluster grid points near specific boundaries before building mesh faces and blocks. But for an automated mesher, dedicated algorithms are needed to generate boundary layer cells. Both CFD-GEOM and CFD-VisCART are capable of generating boundary layer meshes, and they share the same core algorithm.