Tips & Tricks

Cell Size Growth Control in CFD-VisCART

In CFD-VisCART, the Cartesian cells can split or grow by a minimum factor of 2 because of the intrinsic cartesian-cell-splitting algorithm. Due to this, in some cases, there is a chance that the mesh could grow from dense (at the wall) to coarse (away from the wall) within a short distance.

Always Make Sure You Have a Good Mesh Quality

The mesh has a great influence on the solver convergence and solution of every CFD Simulation. The user is strongly advised to check the quality of a numerical mesh.

Wireframe Display in CFD-VisCART

Rotation, zoom, pan and other graphical operations require re-drawing of the model in the new position within the graphics window. When dealing with large models, these operations can slow down considerably due to the huge amount of graphical data that needs to be processed and re-drawn.

Copy/Paste Viewpoint tools

Usually, when performing a particular simulation, it is necessary to compare the results of similar models or the same model at different operating conditions. It is important that the two (or more) cases being compared be viewed from the same angle and at the same zoom level.

Visual Display of Bad Cells in CFD-VisCART

Most models have certain parts or regions where the grid density needs to be higher than other areas to accommodate for steep curvatures, sharply changing topology, etc.

Using Local and Global Body Fit Factors in CFD-VisCART

The 'Body-fit Factor' is a percentage value used to determine how closely the Cartesian mesh front faces are projected to the real geometric surfaces. In other words, the Body-fit factor controls grid quality versus geometric fidelity. The value is between 0% and 100%, where 0%means no projection and 100% means complete projection to the surface.

Surface facet selection tool in CFD-VisCART

CFD-VisCART has always allowed surface selection where any surface can be selected by clicking on the graphics area or in the explorer window. Additionally, there is Facet Selection tool that allows the user to select individual facets or triangles of a surface (each surface is composed of triangulated faces called facets).

Integer Cell Size Specification in CFD-VisCART

As it was explained in a previous tip called Understanding cell-splitting in CFD-VisCART and its effect on cell count, a small change in a specified cell size could lead to drastic changes in the cell count due to the cell-splitting rules used by CFD-VisCART.

Fit to View in CFD-VisCART

In CFD-VisCART, the 'Fit to View' function was improved in V2007. It now checks the blanking status before setting the view. In this tip, a car model will be used to demonstrate the Fit to View capability.

Coloring Surfaces in CFD-VisCART for Better Model Visualization

A typical model imported into CFD-VisCART may contain a number of parts and surfaces. By default, all surfaces come in with the default color (set under Edit → Preferences → Colors → Geometry Colors → Surfaces). Representing these surfaces with different colors would improve the appearance of the model and make it easier for the user to distinguish one surface (or part) from the other.