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Drag curve for a lifting body in steady flight. Parasitic drag, also known as profile drag, [1]: 254 [2]: 256 is a type of aerodynamic drag that acts on any object when the object is moving through a fluid. Parasitic drag is defined as the combination of form drag and skin friction drag. [3] [1]: 641–642 [4]: 19
Skin friction drag is generally expressed in terms of the Reynolds number, which is the ratio between inertial force and viscous force. Total drag can be decomposed into a skin friction drag component and a pressure drag component, where pressure drag includes all other sources of drag including lift-induced drag. [1]
Parasitic drag, or profile drag, is the sum of viscous pressure drag (form drag) and drag due to surface roughness (skin friction drag). Additionally, the presence of multiple bodies in relative proximity may incur so called interference drag , which is sometimes described as a component of parasitic drag.
Therefore, the drag coefficient can often be treated as a constant. [13] For a streamlined body to achieve a low drag coefficient, the boundary layer around the body must remain attached to the surface of the body for as long as possible, causing the wake to be narrow. A high form drag results in a broad wake. The boundary layer will transition ...
is the drag coefficient – a dimensionless coefficient related to the object's geometry and taking into account both skin friction and form drag. If the fluid is a liquid, c d {\displaystyle c_{\rm {d}}} depends on the Reynolds number ; if the fluid is a gas, c d {\displaystyle c_{\rm {d}}} depends on both the Reynolds number and the Mach number .
1) The lead has been changed to explain more consicely the concept of skin friction drag. 2) The part for the Reynolds number has been removed since there is an existing page for the number. 3) Skin friction coefficients for each regime - laminar, transitional, and turbulent - have been added.
Forward resistance comprises the types of drag that impede a sailboat's speed through water (or an ice boat's speed over the surface) include components of parasitic drag, consisting primarily of form drag, which arises because of the shape of the hull, and skin friction, which arises from the friction of the water (for boats) or air (for ice ...
An airfoil is a streamlined shape that is capable of generating significantly more lift than drag. [11] A flat plate can generate lift, but not as much as a streamlined airfoil, and with somewhat higher drag. Most simplified explanations follow one of two basic approaches, based either on Newton's laws of motion or on Bernoulli's principle.