Note that this is a radial gradient, whereas earlier you saw a linear gradient.
One of my favorites is the good old gray to black (or darker gray) radial gradient.
Controlling the source (s) of light in your designs (even if just with a linear or radial gradient) can help create atmosphere in your page designs.
With increasing of superficial gas velocities, the liquid flow regime was changed from homogeneous to transitional and radial gradient of axial liquid velocity was rather small.
