Differential

A differential equation can be defined in either implicit or explicit form as follows.

  : Explicit form

 Implicit form

Where ξ is the differential variable and x is other state variables. The equation can be expressed as a function expression or as User Written Subroutine. Good initial condition helps to converge in the initial assembly process. Value of the differential variable and its derivative can be referenced by DIF and DIF1.

Expressions or user written subroutines can be utilized to define this element. Variable equation elements are defined by the Differential Equation command in the Subentity menu.

Figure 1  Differential icon in the Equation group of the Subentity tab