![]() Consequently, this newer class of liquids/fluids is referred to as non-Newtonion. In the modern era and the advent of polymers and other modern liquids, we now have fluids where this is no longer true. ![]() For the simple and perhaps more natural fluids that existed during Newton’s lifetime (1642-1726), he figured out that the viscosity of most fluids changed only with temperature. These classic fluid properties are named for scientist Sir Isaac Newton. We call these fluids Newtonion because they act in a predictable (classic physics) sort of way. If the moving plate reaction is constant (linear), then the resulting action of the moving pieces represents approximately the same way a Newtonion fluid would react. Note that in this imaginary stack of plates, the second, third and fourth plates in the stack will also move, but with lesser amounts of distance and speed. In the example, you exert a fixed amount of force to the top plate and it consequently moves at a certain speed (velocity) over a specific distance in a measured amount of time. First, imagine you are pushing two or more flat plates or boards stacked on top of one another. TermsĪ set of terms we need to explain to understand viscosity are stress and strain and how they will affect the fluid properties. Note that the opposite or inverse of viscosity is fluidity. Lastly, an alternate method to visualize viscosity is the internal fluid friction resulting when one layer of fluid is forced to move in relation to another layer. Pouring slow means a thicker fluid, which also means a higher viscosity, or you can think of it as possessing a higher resistance to the applied force. Simply put, it pours either fast or slow. To take the viscosity concept another step, it is also that property of a fluid that resists a shearing force. The faster the ball falls, the lower the viscosity of the fluid. One way to visualize viscosity is by watching a metal ball fall through a glass container of the liquid at different speeds for various viscosities. With rare exceptions, the viscosity for every fluid will change indirectly with the temperature if the temperature of the fluid goes up, the viscosity will decrease and vice versa. Viscosity is a fluid’s resistance to flow or pour, but not all fluids resist or react in the same way or even in the same time reference. For a more in-depth, technical article, see my co-contributor’s article from Pumps & Systems, December 2011, by Dr. I was thinking I might take a simpler approach for the purpose of this column.Ī major portion of any discussion regarding the subject concerns viscosity, and I suggest you read my article on the subject ( Pumps & Systems, November 2017). I call non-Newtonian fluids rascals because they do not follow the rules. Every time I review the characteristics of both fluids, I get caught up in the overwhelming array of nomenclature and technical terms. Fluids fall into two classifications-Newtonion or non-Newtonion. What can you do on a non-Newtonian fluid pool? Jump. Bike. Flip.Before you select a pump for any service, you need to know and understand the characteristic properties of the fluid you wish to pump. What can you do on a non-Newtonian fluid pool? Jump. Bike. Flip. Whatever you do, just keep applying high force, or you'll sink right in! What makes non-Newtonian fluids unique is viscosity. Viscosity is the rate at which fluid flows. Common fluids, like water, have a consistent viscosity, so they flow the same regardless of what force you apply. In Non-Newtonian fluids, viscosity can change. Apply a sudden force, and the viscosity rapidly increases, forming a semisolid surface. So the object is stopped, as it would be on solid surface. How can something be a solid and a liquid? In the mix, there are tiny cornstarch particles evenly distributed. When a steady slow force is applied, the particles have time to move out of the way. So the object slides through, as it would in a liquid. When a sudden force is applied, the particles don't have time to move out of the way. These people are "walking on water." The substance is a mix of water and cornstarch. The mixture is two parts cornstarch to one part water. It demonstrates the properties of non-Newtonian fluids. Non-Newtonian fluids are solid if you apply a sudden force and liquid if you apply a steady, slow force. Turns out, walking on water isn't as impossible as it might sound - as long as you have the right kind of water. ![]() Account icon An icon in the shape of a person's head and shoulders.
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