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The INITIAL VALUES section is used to initialize the dependent variables.

 

When not specifically initialized, the dependent variables are initialized to zero.

 

For steady state problems the INITIAL VALUES section is optional.

For time dependent problems, the INITIAL VALUES section should include a value assignment statement for each dependent variable.  

 

Initial value statements are formed by following the dependent variable name with the assignment operator '=' and either a constant, function, expression or previously defined definition.

 

Example:

INITIAL VALUES

U = 1.0-x

 

Setting Initial Values from an imported table:

 

For syntactic reasons, initial values cannot be set directly from TABLE or TRANSFER.  

An intermediate name must be defined by the TABLE or TRANSFER command, and then assigned to the initial value:

DEFINITIONS

TRANSFER("initial_U.xfr",U0)

INITIAL VALUES

U = U0

 

Setting Initial time derivatives:

 

In some problems, especially moving mesh problems, it is important to specify initial time derivatives that are not zero.

This can be done by specifying DT(variable) = expression

 

Example:

INITIAL VALUES

DT(U) = V0

 
See script examples :

Samples | Usage | Moving_Mesh | 1d_stretch_x.pde

Samples | Usage | Moving_Mesh | 2d_stretch_x.pde

Samples | Usage | Moving_Mesh | 2d_stretch_xy.pde