delta_t

delta_t = <float>

Description / Usage

This card is required for transient simulations to set the value of the initial time step. The input parameter is defined as:

<float>

Any floating point number that indicates the time step in the appropriate units for your problem.

To specify a fixed time step size for an analysis, set <float> to be a negative number, e.g. -1.0e-6; the code will use a constant (positive) time step. Should convergence problems occur when a fixed step size is specified, the size of the time increment entered for the delta_t card will be reduced by half until convergence is achieved. Once a constant time step is reduced, it will not be increased.

Examples

Following is a sample card for an initial time step:

delta_t = 6.e-03

If a constant time step is desired, use a negative value:

delta_t = -6.e-03