Don't know how you guys feel about this, so I thought I would ask here first before I make a tutorial. I have been getting good results in generating animated grey-scale displacement maps by using Bryce. I prepare several heightmaps(8) in PS and do a top view altitude render animation in Bryce.

I just apply a new map every thirty keyframes,( frame1, frame30, frame 60,etc) by importing it as a picture height map, and setting keyframes,  The document is 1024x1024  as is the terrain. I then animate the terrain to move a bit on the Z and use a top view position and make sure the terrain completely fills the view. I then select altitude render and render the animation. 

The way Bryce smoothly "tweens", or interpolates between the different heightmaps and the motion from the moving terrain help to sell the look of moving fluid, or water. The best part is that altitude renders are fast.The average frame takes less than fifteen seconds, so a lengthy animation loop can be made in a hurry. I've even done some pretty good water animations in Bryce using this method, so I have no doubt that it would work in Carrara with all its great tools.

Please forgive me if I didn't think of an obvious way to do this in Carrara. I'm sure some of you "grizzled" vets will know of a way to do the same thing in Carrara. But I had an excuse to get some use out of an old app, and one I know pretty well.