Add Normal Drag Node apply drag force by normal of the fluid surface to the Simulation Data. Field velocity is slow down by this node.
!!! This node is not work on the Grid Smoke simulation. !!!

Input / Simulation Data:
Input simulation data for Add Normal Drag. You must connect this input for work.

Input / mask Grid:
Input SDF or Fog grid data for masking. The mask makes gradient effect between min Mask Falloff and max Mask Falloff.
Imported SDF Grid will be convert to Fog grid(surface = 0.0 / deepest = 1.0) and use that value for the gradient and effect.

Output / Simulation Data:
output result simulation data.

Defines on/off status for this function.

Normal Drag:
Defines intensity of the normal drag force.

Invert Mask
Inverts the mask.

min Mask Falloff:
Start (or End) Falloff value. If the mask voxel value is smaller than this, full effect.

max Mask Falloff:
End (or Start) Falloff value. If the mask voxel value is larger than this, no effect.