Gravity
When you add a Gravity node, gravity forces are applied to all selected features in the physics interface with a density, mass, or mass distribution. You select edges (in 2D, boundaries), and all points which belong to the selection are automatically included.
The fluid in the pipe is included in the direction transverse to the pipe, but not in the axial direction. To include the gravity load in the axial direction caused by mass of the fluid, you will typically have to add extra point loads at discontinuities like pipe bends.
The gravity acts in a fixed spatial direction. The load intensity is g = ρgeg where g as a default is the acceleration of gravity (a predefined physical constant). The action of gravity can also be seen as a linearly accelerated frame of reference.
Coordinate System Selection
The Global coordinate system is selected by default. The Coordinate system list contains any additional coordinate systems that the model includes. It can be used when prescribing the direction of the gravitational forces.
Gravity
Enter the components of the Gravity g. The default value is g_const, which is the physical constant having the value 9.8066 m/s2.
For 2D components, the default is that the gravity acts in the negative y direction. For 3D components, the default is that the gravity acts in the negative z direction.
Only features which have a geometrical selection contribute to the mass forces. The Mass and Moment of Inertia nodes are global features and will not get any contribution from Gravity.
You can add a Harmonic Perturbation subnode for specifying a harmonic variation of the values of the prescribed displacements and rotations in a frequency domain analysis of perturbation type.
Location in User Interface
Context Menus
Ribbon
Physics tab with Pipe Mechanics selected: