User Manual

BCs - Variation - Function:

A Function Variation may be defined by selecting the BC's-Variation-Function menu

A variation is used to define a variable boundary condition (of any type).

The user identifies an independent variable ( X, Y, Z, time or Temperature) and then defines how the dependent variable,determined by the type of boundary condition referencing the variation, changes.

A variation is simply a definition of how one variable changes with respect to the another ( e.g. heat input as a function of time).No interpretation about what is varying (heat, temperature, etc.) is made until the variation is associated to a specific boundary condition type.

Defining a variable boundary condition is a two step process. First the variation is defined; next the BC is created so as to reference the defined variation.  In this way, multiple boundary conditions that vary in the same manner may reference the same variation.

The user selects the function type to be defined: polynomial, sinusoidal or exponential. After the function type has been selected, the independent variable is specified (this may be x, y, z, time or temperature).

Enter the name of the function to be created after clicking the "Create New Function" Button. Next, the equation type, coefficients, the starting and ending points of the independent variable for each interval is defined. The user may mark whether the function is to be interpreted as periodic (for transient models only). The inverse function option is selected to take reciprocal of the defined function. Once the functions have been defined, they will become available as valid picks from any of the boundary condition forms.

Thermostat:

This function is accessed from the "function Variation" menu. Thermostat is a on/off( 1 or 0) multiplier on the function.

Enter the coordinates of the sensor point and the on (low) and off (high) temperatures. When the temperature at the sensor location, for example, reaches above the high temperature specified the function will be turned off and when the temperature at the sensor location reaches below the low temperature specified the function will turn on.