{"id":2952,"date":"2025-08-11T16:20:36","date_gmt":"2025-08-11T10:50:36","guid":{"rendered":"https:\/\/study.madeeasy.in\/?p=2952"},"modified":"2025-08-13T18:57:07","modified_gmt":"2025-08-13T13:27:07","slug":"viscosity","status":"publish","type":"post","link":"https:\/\/www.madeeasy.in\/study\/ce\/fluid-mechanics\/viscosity","title":{"rendered":"Viscosity in fluid Mechanics"},"content":{"rendered":"

What is Viscosity in fluid mechanics?<\/strong><\/h2>\n

Viscosity is the property of fluids by virtue of which they offer resistance to shear or angular deformation.<\/p>\n

It is primarily due to cohesion (in case of liquids) and molecular momentum exchange (in case of gases) between fluid layers, and as flow occurs, these effects appear as shearing stresses between the moving layers.<\/p>\n

\"Viscosity\"<\/p>\n

Consider a fluid element between the two infinite plates. The rectangular fluid element is initially at rest at time t. Let us now suppose a constant rightward force \u03b4Fx<\/sub> is applied to the upper plate so that it is dragged across the fluid at constant velocity \u03b4u. The relative shearing action of the plates produces a shear stress, \u03c4yx<\/sub> , which acts on the fluid element and is given by<\/p>\n

\"Deformation\"<\/p>\n

where \u03b4Ayis the area of contact of the fluid element with the plate and \u03b4Fx<\/sub> is the force exerted by the plate on that element.
\nVarious positions of the fluid element<\/a>, illustrate the deformation of the fluid element from position MNOP at time t, to M\u2032NOP\u2032 at time t + \u03b4t, to M\u2033NOP\u2033 at time t + 2\u03b4t, due to the imposed shear stress. The deformation of the fluid is given by<\/p>\n

\"Deformation\"<\/p>\n

Distance between the points M and M\u2032 is given by,<\/p>\n

\"Deformation<\/p>\n

Thus, the rate of angular deformation is equal to velocity gradient across the flow.<\/p>\n

\n
\n

Table of Contents<\/p>\nToggle<\/span><\/path><\/svg><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n