Interior Velocity
Use the Interior Velocity node to specify a velocity on an interior boundary in thermoviscous acoustics. The condition can be used to specify sources, for example, the velocity of a diaphragm in a miniature transducer that is modeled using a lumped circuit model. The velocity components can be prescribed independently, and there is an option to force continuity in pressure across the boundary, as well as options for the thermal conditions.
Mechanical
Select the Continuous pressure check box if the velocity condition is to be used as a source where the pressure should not be slit.
To define a prescribed velocity for each space direction (x and y, plus z for 3D), 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).
To define a prescribed velocity for each space direction (r and z), select one or both of the Prescribed in r direction and Prescribed in z direction check boxes. Then enter a value or expression for the prescribed velocities u0r or u0z (SI unit: m/s).
Thermal
Select a Thermal condition — Isothermal (the default) or Adiabatic. See the Isothermal and Adiabatic conditions for further details.
Constraint Settings
To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog box. For the Interior Velocity condition the Constraint method is set to Nodal.
Excluded Edges/Points
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.