Comment by toss1
19 hours ago
Yes, but this is not that.
Golf ball dimples are about 4 mm across and 0.2mm or 200μm (micrometers).
These features are several orders of magnitude smaller at 38 to 53μm diameter.
>>the first in the world to demonstrate that aerodynamic drag can be reduced by up to 43.6 percent simply by applying distributed micro-roughness (DMR), a surface roughness so fine and irregular that it cannot be distinguished by the naked eye. [...] Two types of DMRs were used in this experiment: A convex pattern made of glass beads with diameters ranging from 38 to 53 micrometers (μm) and a concave pattern applied by sandblasting. The height of the DMR coating is only 1 percent of the thickness of the boundary layer and is classified as a “smooth surface” from a hydrodynamic point of view.
Not to be that guy, but 38-53um is 1 order of magnitude smaller than 200um
Not to be that guy ;-) , but the diameter of the golf ball dimples is ~4 mm or about 4,000 μm, whilst the diameter of the spheres is 38-53 μm, or about 0.04 mm.
Diameter-to-diameter seems like about 100x or two orders of magnitude?
Similarly, 200 μm is the golf ball dimple depth (oops, just noticed I dropped that key word), and they didn't give us a measurement of the depth of the dents caused by the spheres or sandblasting, but it would likely be significantly less than half the radius of the spheres?
Sorry about misleading with dropping the "depth" word.