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Drag coefficients in fluids with Reynolds number approximately 10 4 [1] [2] Shapes are depicted with the same projected frontal area. In fluid dynamics, the drag coefficient (commonly denoted as: , or ) is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment, such as air or water.
Drag is a force that acts parallel to and in the same direction as the airflow. The drag coefficient of an automobile measures the way the automobile passes through the surrounding air. When automobile companies design a new vehicle they take into consideration the automobile drag coefficient in addition to the other performance characteristics ...
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 .
Drag and lift coefficients for the NACA 63 3 618 airfoil. Full curves are lift, dashed drag; red curves have R e = 3·10 6, blue 9·10 6. Coefficients of lift and drag against angle of attack. Curve showing induced drag, parasitic drag and total drag as a function of airspeed. Drag curve for the NACA 63 3 618 airfoil, colour-coded as opposite plot.
Iron deficiency, or sideropenia, is the state in which a body lacks enough iron to supply its needs. Iron is present in all cells in the human body and has several vital functions, such as carrying oxygen to the tissues from the lungs as a key component of the hemoglobin protein, acting as a transport medium for electrons within the cells in the form of cytochromes, and facilitating oxygen ...
An analysis of data from more than 8,000 adults in the U.S. revealed that 14% had low iron blood levels, a condition known as absolute iron deficiency, while 15% had the right iron levels but ...
In mechanics and aerodynamics, the drag area of an object represents the effective size of the object as it is "seen" by the fluid flow around it. The drag area is usually expressed as a product , where is a representative area of the object, and is the drag coefficient, which represents what shape it has and how streamlined it is.
A n are experimentally determined coefficients. For air (Davies, 1945): [2] A 1 = 1.257 A 2 = 0.400 A 3 = 0.55. The Cunningham correction factor becomes significant when particles become smaller than 15 micrometers, for air at ambient conditions. For sub-micrometer particles, Brownian motion must be taken into account.