3.4 Vector and Dimension Macros

ANSYS FLUENT provides some utilities that you can use in your UDFs to access or manipulate vector quantities and deal with two and three dimensions. These utilities are implemented as macros in the code.

There is a naming convention for vector utility macros. V denotes a vector, S denotes a scalar, and D denotes a sequence of three vector components of which the third is always ignored for a two-dimensional calculation. The standard order of operations convention of parentheses, exponents, multiplication, division, addition, and subtraction (PEMDAS) is not followed in vector functions. Instead, the underscore ( _) sign is used to group operands into pairs, so that operations are performed on the elements of pairs before they are performed on groups.

Note that all of the vector utilities in this section have been designed to work correctly in 2D and 3D. Consequently, you don't need to do any testing to determine this in your UDF.