I have created a water simulation and set a cube inside the domain to fluid. I was wondering what the best way to make a big lake of water (with realistic ripples) would be. No tutorials seem to go beyond still images or using an inflow. In my final render I plan to have the scene at night, and have a shot low to the water, then have the camera glide just over the water. I am hoping the water will look something like this:
For a large rippling body of water such as a lake, rather than use a fluid simulation (which would require a great deal of simulation time to get believable results) you can combine multiple waves to give the effect of ripples on the surface of the fluid - similar to that in this answer. However, if you don't need it to be seamless, you can use Wave textures instead of plain Sine waves with the Distortion significantly increased - this will reduce the number of waves you need to combine to get a believable result.
For example, consider the following material :
Here, two Wave textures with high noise are combined via an Add maths node and used to drive the Bump of a flat plane. Note that one of the Wave textures has been rotated via the Mapping node.
The Value node is keyframed to vary the offset of the Wave textures - to move the waves 'forward' as the animation progresses.
By adjusting the rotation, Scale, and other Texture parameters you can get quite a pleasing effect as follows :
Note that this is using the Bump node to generate the Normal. If the water will be viewed from a very shallow angle it may be preferable to add geometry and use True Displacement to create actual waves in the mesh.