To specify the displacement of an eigenmode as a sequence of piecewise states a Tecplot formatted ASCII file (refer to the 'Tecplot Data Format Guide') must be provided. For each piecewise state the following variables must be specified:

Variables required to define a piecewise state

Variable	Description
`DurationTime`	Time duration [seconds] in which the modal displacement will transit from its existing value to the current state's value
`ModalDisplacementReal`	Modal displacement to be held until the control state condition is satisfied
`DisplacementControlState`	Control condition to be satisfied before moving to the next state

Note: DisplacementControlState may be either 0 = CONTROL_OPTION_SURGE_RELEASE, 1 = CONTROL_OPTION_SURGE_THROTTLE or 2 = CONTROL_OPTION_TIME.

Description of the displacement control states

DisplacementControlState	Description
CONTROL_OPTION_SURGE_RELEASE	Modal displacement is held at the specified value until the mass flow raises above the threshold at the control surface
CONTROL_OPTION_SURGE_THROTTLE	Modal displacement is held at the specified value until the mass flow sinks below the threshold at the control surface
CONTROL_OPTION_TIME	modal displacement is held until DurationTime is reached

Note: See UseSurgeControl for the commands used to specify the thresholds and activate piecewise displacements.

Example: Piecewise displacement comprising three states. File header in Tecplot format:
TITLE = "Piecewise Displacement"

VARIABLES = "DurationTime" "ModalDisplacementReal" "DisplacementControlState"

ZONE T = "States", I = 3, DATAPACKING = POINT, ZONETYPE = ORDERED

0.001 0.500 1

0.001 -0.500 0

0.001 0.000 2