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Skin friction drag is caused by the viscosity of fluids and is developed from laminar drag to turbulent drag as a fluid moves on the surface of an object. Skin friction drag is generally expressed in terms of the Reynolds number , which is the ratio between inertial force and viscous force.
Skin friction arises from the interaction between the fluid and the skin of the body, and is directly related to the area of the surface of the body that is in contact with the fluid. Skin friction follows the drag equation and rises with the square of the velocity. Skin friction is caused by viscous drag in the boundary layer around the object ...
Compared to the predictions of inviscid flow theory, in which there is no boundary layer, the attached boundary layer reduces the lift by a modest amount and modifies the pressure distribution somewhat, which results in a viscosity-related pressure drag over and above the skin friction drag. The total of the skin friction drag and the viscosity ...
However, it is often convenient to talk about a body force in terms of either the force per unit volume or the force per unit mass. If the force per unit volume is of interest, it is referred to as the force density throughout the system. A body force is distinct from a contact force in that the force does not require contact for transmission.
Chafing is an irritation or superficial abrasion of skin caused by friction, moisture or irritating fabric. Prolonged rubbing on the skin may result in skin sting or burn, and development of a mild, red rash or boils; and in severe cases may include swelling, bleeding, or crusting. It often results from body parts that rub against each other or ...
A wheeled buffalo figurine—probably a children's toy—from Magna Graecia in archaic Greece [1]. Several organisms are capable of rolling locomotion. However, true wheels and propellers—despite their utility in human vehicles—do not play a significant role in the movement of living things (with the exception of the corkscrew-like flagella of many prokaryotes).
In addition, medicine can be administered through the skin, by ointments or by means of adhesive patch, such as the nicotine patch or iontophoresis. The skin is an important site of transport in many other organisms. Water resistance: The skin acts as a water-resistant barrier so essential nutrients are not washed out of the body. [32]
The skin is susceptible to burns, and burns to the skin often cause blistering. Abrasive trauma scrapes or rubs off the skin, and severe abrasions require skin grafting to repair. Skin tears involve the removal of the epidermis or dermis through friction or shearing forces, often in vulnerable populations such as the elderly.