Use the Velocity node to define the prescribed velocities u0 on the boundary. Add this node from the Mechanical submenu. The condition reads ut = u0. This condition is useful, for example, when modeling a vibrating wall/source.

Select the Coordinate system to define the orientation of the prescribed quantities (the velocity). The default is the Global coordinate system, any other applicable system will be listed.

To define a prescribed velocity for each space direction, select one or more of the Prescribed in x direction, Prescribed in y direction, and Prescribed in z direction check boxes. Then enter a value or expression for the prescribed velocities u0x, u0y, or u0z (SI unit: m/s), here given in a 3D component and for the Global coordinate system selection. The prescribed values that you specify are interpreted in the selected Coordinate system and space dimension.

To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog box. For the Velocity condition the Constraint method is set to Nodal.

To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog box. See Suppressing Constraints on Lower Dimensions for details.