What does Viscosity mean in Fluid Mechanics ?
Viscosity can be defined as the resistance of fluids to angular deformation under shear stress. In simpler terms, viscosity is the resistance of a fluid to flow. In general, as the temperature increases, the viscosity of fluids decreases. The main reason for this is that the forces between molecules decrease and free flow occurs as the temperature increases. Under pressure, the viscosity of many fluids remains constant, while at very high pressures, the viscosity increases as the pressure increases. Fluids that do not resist surface stresses under shear stress are called ideal fluids, so the viscosity of ideal fluids becomes zero. However, it is difficult to find such a fluid in nature.