牛顿和非牛顿流感之间的区别ids

Thekey differencebetween Newtonian and non Newtonian fluids isthat Newtonian fluids have a constantviscosity, whereas non-Newtonian fluids have a variable viscosity.

我们可以根据液体的粘度，将流体（即液体和气体）分为牛顿或非牛顿。由于流体的内部摩擦，粘度是厚而粘稠的状态。此外，我们需要考虑确定流体是牛顿还是非牛顿的其他参数。这些是剪切应力和剪切速率。Shear stressis the stress applied coplanar on the fluid cross-section while shear rate is the rate of change of速度一层流体通过相邻层。

内容

1.Overview and Key Difference
2.What is Newtonian Fluid
3.什么是牛顿液
4.Side by Side Comparison – Newtonian vs Non Newtonian Fluids in Tabular Form
5.概括

What is Newtonian Fluid?

Newtonian fluids are fluids having a constant viscosity and a zero shear rate at zero shear stress. That means; the shear rate is directly proportional to shear stress. In other words, the ratio of the shear stress to the shear rate is constant throughout the fluid.

However, most fluids we know have a variable viscosity. Usually, no real fluids fit the definition exactly. Therefore, it is considered as a simple mathematical model. But we can assume some common liquids and gases such as water and air as Newtonian fluids. The name Newtonian comes from Isaac Newton, who was the first scientist to use a differential equation to postulate the relationship between shear stress and shear rate of fluids.

什么是牛顿液？

Non-Newtonian fluids are the fluids that have a variable viscosity and a variable relationship with shear stress. It is because these fluids do not follow Newton’s law of viscosity. The viscosity of these fluids can change under force. i.e. some liquids such as sauce are runnier when the bottle is shaken. Most fluids we know are non-Newtonian fluids. Many salt solutions, molten polymers and many other fluids can be categorized into this group.

Although we use the term viscosity in fluid mechanics to describe the shear properties of a fluid, it is not adequate to describe the properties of non-Newtonian fluids. There are different behavioural characteristics of non-Newtonian fluids including viscoelasticity, time-dependent viscosity, etc.

牛顿和非牛顿液有什么区别？

液体可以分为两种类型，具体取决于粘度为牛顿液和非牛顿液。牛顿液和非牛顿流体之间的主要区别在于，牛顿液具有恒定的粘度，而非牛顿液的粘度可变。此外，在考虑剪切速率和剪切应力时，在牛顿液中，我们可以在零剪切应力下观察到零剪切速率。这意味着；剪切速率与剪切应力直接成正比。但是，非牛顿液在剪切速率和剪切应力之间具有可变关系。

Although most fluids we know are non-Newtonian fluids, water and air are considered as Newtonian fluids at normal conditions. However, almost all salts, molten polymer material, blood, toothpaste, paint, corn starch and many other varieties of fluids are non-Newtonian fluids.

The below infographic summarizes the difference between Newtonian and non Newtonian fluids.

摘要 - 牛顿与非牛顿液

液体可以分为两种类型，具体取决于粘度为牛顿液和非牛顿液。The key difference between Newtonian and non Newtonian fluids is that Newtonian fluids have a constant viscosity, whereas non-Newtonian fluids have a variable viscosity.

Reference:

1. Coussot, P. “Introduction to the Rheology of Complex Fluids.” Understanding the Rheology of Concrete, 2012, pp. 3–22., doi:10.1533/9780857095282.1.3.
2. “Newtonian Fluid.” Wikipedia, Wikimedia Foundation, 13 Oct. 2019,Available here.
3. “Non-Newtonian Fluid.” Wikipedia, Wikimedia Foundation, 8 Sept. 2019,Available here.

Image Courtesy:

1. “Dilatant-pseudoplastic” By DirectEON (talk) 08:46, 28 March 2008 (UTC) – self-made(CC BY-SA 3.0)viaCommons Wikimedia
2. “paddling pool cornstarch 9” ByTrevor Cox(CC BY-SA 2.0)viaFlickr