Impose Acceleration

Analysis > Boundary Conditions > Regions > Impose Acceleration

Introduction

The impose acceleration region imposes a defined acceleration on all the particles which are within the defined region. It also can be thought of as a momentum source region, except that by defining the acceleration instead of hard setting the velocity of the particles, the region is likely to behave more stably.

Description

  • The fluid acceleration region can be specified in a cuboid (parallelepiped), or cylindrical shape and it hard-imposes acceleration on all particles which are within the prescribed region.
Following imposed acceleration types can be defined,
  • PARALLELEPIPEDACC
  • CYLINDERACC
Acceleration Type
  • Constant - Imposed acceleration inside the region.
  • Time Series - Defines variable acceleration inside the imposed region.

Cylinder cap - Controls adding of hemispherical caps on the cylinder bases (resulting in a pill-shape geometry). The caps are added to both sides of the cylinder.

Start Time / End Time - Specifies the start and finish times which define the window where the impose region is active.

Damping Time - Damping time of the prescribed acceleration.

Advanced Options
  • Mode - Defines the mode of the impose region, are the specified values added or set inside the impose region. Options are SET, ADD.
  • Constraint - Defines the constraint of the impose region, are the specified values strictly or loosely imposed in the region. Options are: LOOSE, STRICT.
  • Moving body motion to follow - Impose regions can follow a MOVINGWALL phase with a predefined motion.

Other Options - A free text box where additional parameters can be specified.