Fluid animation with varying speed How can I animate the fluid so it starts with a normal speed and then changes to slow motion?

I have one 1/4 second fluid simulation played over 24 frames (one second):



Now I'd like it to slow down and play second quarter of simulation over the next, say, 72 frames.

I tried changing the timeline Start and End frames to 25 and 96 respectively, setting the simulation time Start to 0.25 and End to 0.5, and setting cache offset to 25 and bake again, but it seems to overwrite the previous bake i.e. the normal speed simulation in frames 1-24 is substituted with the slow simulation. Obviously it's not the way to go.



(I'd post more screenshots but don't have rep for that yet ;))

How would I go about it? Do I need two domains for different animation speeds or is there some way to keyframe the liquid?

Note that I'm quite new to Blender so there are some basics I still need to learn, but I find it easier to learn them when I have specific goal in mind. Thanks for understanding ;).
I know it's a late reply, but I think I can help, if I understand correctly.

You can use keyframes on fluid simulations.  The best way to slow down the simulation is to set keyframes in the "Speed" field. 



You will have to set the keyframes and then rebake the fluid simulation so they can be applied, this can be annoying if you are using a large domain and/or high resolution to the simulation as it can take a long time to bake and rebake till its right, so it's better to bake it with a small domain and low resolution so that you can quickly check to see if the fluid is behaving the way you want, then crank-up the domain size/resolution for your final render.