Margin

– Amount of extra space to leave around smoke, measured in voxels. With very fast-moving smoke larger margins may be required to prevent the smoke from being cut off by the adaptive boundary.
– Attention: this will increase the computational time.

– In this example note how the adaptive domain stay far from the smoke until reaching the domain maximum size:

– The behavior of the smokes are different expecially at the beginning, during the adaptive domain expansion:

Blender Fluid Gas Adaptive Domain Margin