Hydrodynamically rough surface

{
  "id": "MLC-T-MET-006315",
  "term": "Hydrodynamically rough surface",
  "field": "Meteorology and atmospheric science",
  "definition": "A surface where the roughness elements are large enough to protrude through the viscous sublayer of a fluid flow, causing turbulence to be generated directly by these elements. This condition results in a drag coefficient that depends on the relative roughness height rather than the Reynolds number. Examples include a forest canopy or a field of tall crops in atmospheric boundary layer studies.",
  "see_also": [
    "friction velocity",
    "zero-plane displacement",
    "aerodynamically rough surface",
    "aerodynamically smooth surface"
  ],
  "url": "https://mlchart.com/terminology/meteorology/hydrodynamically-rough-surface/"
}