The video below shows several different long chained oils, each progressively more viscous. Glycerol, CH 2OHCHOHCH 2OH, is viscous partly because of the length of the chain but also because of the extensive possibilities for hydrogen bonding between the molecules. Fuel oil, lubricating grease, and other long-chain alkane molecules are quite viscous for this reason. This is because the molecular chains get tangled up in each other like spaghetti-in order for the liquid to flow, the molecules must first unravel. (For example, when you ride a bicycle at 10 m/s in still air, you feel the air in your face exactly as if you were stationary in a 10-m/s wind.) Flow of the stationary fluid around a moving object may be laminar, turbulent, or a combination of the. Liquids containing long molecules are invariably very viscous. A moving object in a viscous fluid is equivalent to a stationary object in a flowing fluid stream. Honey, mostly glucose and fructose (see image below) is a good example of a liquid which owes its viscosity to hydrogen bonding. The density and viscosity of a compressible fluid increase as pressure increases but tend to level off at high pressures. Unlike other resistive forces, such as dry friction, which are. A compressible fluid has orders of magnitude higher compressibility than that of a slightly compressible fluid, usually 10 2 to 10 4 psi 1 depending on pressure. 1 This can exist between two fluid layers (or surfaces) or between a fluid and a solid surface. Liquids whose molecules are polar or can form hydrogen bonds are usually more viscous than similar nonpolar substances. Drag (physics) In fluid dynamics, drag (sometimes called fluid resistance) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. Viscosity is governed by the strength of intermolecular forces and especially by the shapes of the molecules of a liquid. Those like ether or gasoline which flow very readily have low viscosities. Rheopectic: The viscosity of these fluids increases when shear stress is applied along with time. These fluids are the opposite of dilatant fluids. Pseudoplastic: The viscosity of these fluids decreases when shear stress is applied. Examples of herbs, shrubs, climbers, creepers How do we convert 1 g/cm3 to. Viscosity for a fluid is the measure of its resistance to a gradual change in shape by shear stress or tensile stress. Quicksand, cornflour with water, and putty are examples of dilatant fluids. Liquids which flow very slowly, like glycerin or honey, have high viscosities. The matter with high viscosity is known as Viscous fluid. The resistance to such flow is called the viscosity. \)īecause its molecules can slide around each other, a liquid has the ability to flow.
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