Prescribed Velocity

The node adds a boundary or domain condition where the velocity is prescribed in one or more directions. The prescribed velocity condition is applicable for Time Dependent and Frequency Domain studies. It is possible to prescribe a velocity in one direction, leaving the solid free in the other directions. The node is a constraint and overrides any other constraint on the same selection.

The node is only available with some COMSOL products (see http://www.comsol.com/products/specifications/).


	For details about prescribed velocities and accelerations, see Prescribed Displacements, Velocities, and Accelerations.

Layer Selection

This section is only present in the in the Layered Shell interface, where it is described in the documentation for the Prescribed Velocity and Prescribed Velocity, Interface nodes.

Coordinate System Selection

Select a coordinate system in which the given velocity components will be interpreted.


	Coordinate systems with directions that change with time should not be used for a prescribed velocity.

Prescribed Velocity

Select one or all of the ,, and for 3D components, check boxes. Then enter a value or expression for vx, vy, and for 3D components, vz. For 2D axisymmetric components, select one or both of the and check boxes. Then enter a value or expression for vr and vz.

In a stationary study, this node can either be ignored or treated as a constraint (similar to a node with zero displacement). To control this, select an option from the list — or .

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You can add a Harmonic Perturbation subnode for specifying a harmonic variation of the values of the prescribed displacements in a frequency domain analysis of perturbation type.

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You can activate and deactivate this boundary condition by assigning it to a constraint group. See Load Cases in the Structural Mechanics Modeling chapter.

Location in User Interface

Context Menus

(Boundary)
(Edge)
(Edge)
(Point)

Ribbon

Physics tab with selected: