Takes the fluid dynamics object to take the velocities from (defined by the dynamics node internal velocity field).

Activates the force only to be defined inside of liquid (a liquid dynamics node must be assigned in the Fluid Simulation Solver field).

Defines which time step to use. Remember that the velocities extracted from the velocity field do not include substep information.

Simulation
Uses the simulation time step

Cinema 4D
Use the time step defined by Cinema 4D

Custom
Uses a user-defined time step set with 'Time Step'

Only available if Time Step mode is set to 'Custom'. You can set a custom time step (in seconds) here. The default of 0.033 is a full C4D frame at 30fps (1/30 = 0.033).
If your scene uses 25fps, you would set this value to 1/25 = 0.04.

The overall strength of the force.

Mograph clones or particles for example can have an own motion force. This slider allows to mix the original force of the affected objects/particles with the velocities of the fluid simulation.
That way you can let particles be driven completely by the fluid flow instead of including their existing motion.

Defines the amount of flow resistance. Can simulate artistically some drag occuring. Helps with showing that the objects/particles affected have a different weight.

Defines the amount of buoyancy (rising of matter) included. This is a non-physical value.