With the Free Surface modeling capability, you can dynamically simulate the interface between liquids and gases. This ability is essential for modeling flow phenomena such as waves, sloshing, and spilling. These are flows that occur in nature as well as in a wide range of engineering applications.
There are two ways to define the forces that affect the liquid: as a gravity force or as externally-applied acceleration components.
Use Gravity to include the effects of elevation change on the liquid. Specify a Gravity unit vector to indicate the direction of the pull of gravity.
Use Acceleration to simulate body forces experienced by the liquid. An example is a liquid transport tank in which the liquid sloshes due to movement of the vehicle. As the vehicle turns, the liquid experiences accelerations. There are two ways to specify acceleration components: as constants or as time-varying. The units for both methods are (geometry units)/s2. For example, if your model is in meters, specify acceleration in m/s2.
To simulate an acceleration that does not vary with time, select Constant, and specify the value.
To define a time variation of an acceleration component, select Piecewise Linear, and click Edit. Use a transient definition to account for changes in acceleration with time. In the tank-in-transit example, this allows us to accurately represent the physical motion of the liquid.
In the Acceleration Curve Editor dialog, specify the Acceleration value and corresponding Time values. The units for Acceleration are always (geometry units)/s2. For example, if your model is in meters, acceleration units are m/s2. The units of Time are always seconds.
Click here for more about simulating Free Surface flows.