![]() ![]() The table below summarises four types of non-Newtonian fluids. Some non-Newtonian fluids react as a result of the amount of stress applied, while others react as a result of the length of time that stress is applied. Not all non-Newtonian Fluids behave in the same way when stress is applied – some become more solid, others more fluid. In this case, the oobleck’s viscosity or resistance to flow increases with applied stress. You can roll it into a solid ball in your hand, but if you stop moving it, it reverts to liquid and oozes out through your fingers. You can hit a bowlful with a hammer, and instead of splashing everywhere, the particles lock together. This liquid is a runny goo until you apply stress to it, and then it suddenly acts like a solid. Oobleck is a mixture of cornflour and water (similar to uncooked custard) named after a substance in a Dr Seuss book. viscosity, resistance of a fluid (liquid or gas) to a change in shape, or movement of neighbouring portions relative to one another. In this case, the sauce’s viscosity decreases and it gets runnier with applied stress. This causes the tomato sauce to become more liquid and you can easily squirt some out. It can be computed with the following formula: Viscosity ( force distance between two layers of fluid ) / (. ![]() ![]() So what do you do? You shake or hit the bottle. Viscosity is the ratio of the shear stress to the velocity of the gradient. You know there is some in there, but when you turn the bottle upside down, nothing comes out. Say you want to get some tomato sauce out of the bottle. Remove the stress (let them sit still or only move them slowly) and they will return to their earlier state. If you apply a force to such fluids (say you hit, shake or jump on them), the sudden application of stress can cause them to get thicker and act like a solid, or in some cases it results in the opposite behaviour and they may get runnier than they were before. It is measured by a viscometer, of which there are various designs commonly based on the time taken to flow through an orifice or a capillary tube when at a standard temperature. It is commonly perceived as resistance to pouring. Non-Newtonian fluids change their viscosity or flow behaviour under stress. Viscosity is a measure of the resistance of a fluid to deform under shear stress. ![]()
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