Drag (physics)

  • shape and flow form
    drag
    skin
    friction
    flow plate.svg 0% 100%
    flow foil.svg ~10% ~90%
    flow sphere.svg ~90% ~10%
    flow plate perpendicular.svg 100% 0%

    in fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid.[1] this can exist between two fluid layers (or surfaces) or a fluid and a solid surface. unlike other resistive forces, such as dry friction, which are nearly independent of velocity, drag forces depend on velocity.[2][3] drag force is proportional to the velocity for a laminar flow and the squared velocity for a turbulent flow. even though the ultimate cause of a drag is viscous friction, the turbulent drag is independent of viscosity.[4]

    drag forces always decrease fluid velocity relative to the solid object in the fluid's path.

  • examples of drag
  • types of drag
  • drag at high velocity
  • very low reynolds numbers: stokes' drag
  • aerodynamics
  • d'alembert's paradox
  • see also
  • references
  • bibliography
  • external links

Shape and flow Form
Drag
Skin
friction
Flow plate.svg 0% 100%
Flow foil.svg ~10% ~90%
Flow sphere.svg ~90% ~10%
Flow plate perpendicular.svg 100% 0%

In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid.[1] This can exist between two fluid layers (or surfaces) or a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, drag forces depend on velocity.[2][3] Drag force is proportional to the velocity for a laminar flow and the squared velocity for a turbulent flow. Even though the ultimate cause of a drag is viscous friction, the turbulent drag is independent of viscosity.[4]

Drag forces always decrease fluid velocity relative to the solid object in the fluid's path.