![]() ![]() Mathematically, this relationship can be expressed as: A Newtonian fluid is a fluid whose viscosity remains constant, regardless of the applied shear stress or shear rate. To quantify dynamic viscosity, we rely on Newton’s law of viscosity, a fundamental equation that describes the relationship between shear stress and shear rate in a Newtonian fluid. By calculating the dynamic viscosity of a fluid, we gain insight into its behavior under different conditions and can predict how it will respond to external forces. The SI unit used to quantify dynamic viscosity is the pascal-second (Pas). In other words, dynamic viscosity helps us understand how a fluid responds when force is applied to deform it. It’s the measure of a fluid’s resistance to shear or tensile stress. Dynamic Viscosityĭynamic viscosity, also known as absolute viscosity, is one of the two key ways we measure viscosity. Kinematic Viscosity: This is the measure of the flow of the fluid’s internal resistance as a result of the influence of the force of gravity. Hence, fluids move in the opposite direction at different speedsī. This is a force that is required by the fluid to defeat the internal molecular friction so that it can encourage the flow of the fluid. Dynamic Viscosity: This is the resistance to the flow of one layer of fluid in relation to the other. We have two types of viscosity: Dynamic and kinematicĪ. Therefore, we have dimension as ML -1T -1. Hence, by using η = F / (AV) we will have Where Force, F = Newtons = kgm/s 2 = MLT -2 We can derive the dimension of viscosity by applying the formula The derived standard international (SI) unit of dynamic viscosity is poiseiulle (PI). We measure viscosity in Newton seconds per meter square (Ns/m 2) or in Pascal seconds (Pas), and it’s a vector quantity. Η = Constant of proportionality called the coefficient of viscosity Therefore, the force exerted between the two layers will be directly proportional to the velocity gradient and the surface area A.The velocities of adjacent layers A and B are V 1 and V 2 respectively. ![]() When layers of water flow slowly and steadily through a pipe, it will be observed that each layer flows at different velocities. The formula for calculating viscosity is:Ĭoefficient of viscosity, η = Force (F) / Viscosity Definition: What is the SI Unit of Viscosity and its Formula Therefore, we can say that viscosity is friction in liquids. Hence very cold thick palm oil is more viscous than very cold water. We consider liquids that pour slowly to be more viscous than those which pour faster. The thicker a liquid is, the higher its viscosity. Hence, honey tends to resist the motion of objects between its layers due to its thickness. We need to remember that friction is a force that resists motion. The honey is thicker and encourages more internal friction between its layers. Therefore, the differences are due to the internal friction between the layers of the fluids. When we observe fluids in motion, we are witnessing the effects of viscosity, which manifests as the resistance these fluids offer to any attempt to move them. This essential property helps us understand how different fluids behave and interact with their surroundings. It is the name given to internal friction that exists between the layers of the molecules of fluids (liquid or gas) in contact with surfaces.Īdditionally, viscosity, in fluid dynamics, is the measure of a fluid’s resistance to flow. It is the property of a liquid that opposes the relative motion between different layers. Viscosity Definition: We can define viscosity as the internal friction between layers of a liquid or gas in motion. Differences Between Viscosity and Friction Similarities Between Viscosity and Friction Classification of Fluids According to Their Viscous Properties
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |