Name: newtonian vs non-newtonian fluid behavior
Uploaded: 2025-02-13T15:43:08.000Z
Duration: 1 min 27 s
Channel: JoVE

流体は、ニュートンと非ニュートンの2つの主要なタイプに分類されます。ニュートン流体は粘度が一定で、そのせん断応力はせん断ひずみ速度に線形に関連しています。
ニュートン流体の振る舞いは予測可能です。例としては、水、空気、油、ガソリンなどがあります。
ただし、非ニュートン流体は、せん断速度に基づいて粘度が変化します。それらは、せん断減粘、せん断増粘、およびビンガムプラスチックに分けられます。
ラテックス塗料やポリマー溶液などのせん断減粘液は、せん断速度が増加すると見かけの粘度が低下し、せん断時に流動性が高くなります。
このプロパティは、ブラシ ペイントやインクジェット印刷など、滑らかで均一な塗布が必要なアプリケーションで役立ちます。
水中のコーンスターチなどのせん断増粘液は、より高いせん断速度で見かけの粘度が増加し、攪拌すると流れに対してより抵抗力が高くなります。
このユニークな特性により、保護具やダンピングデバイスに役立ちます。
歯磨き粉やマヨネーズなどのビンガムプラスチックは、降伏応力を超えると固体として動作し、その後流体のように流れるため、押し出しや広がりが必要な製品に最適です。

流体の種類

Types of Fluids

流体は、せん断応力に対する反応に基づいて、ニュートン流体と非ニュートン流体に分類できます。ニュートン流体は、せん断応力とせん断ひずみ速度の間に直線関係があり、ニュートンの粘性法則に従います。その粘度はせん断速度に関係なく一定であるため、挙動を予測でき、分析が容易です。一般的な例としては、水、空気、油、ガソリンなどがあります。

 対照的に、非ニュートン流体はニュートンの粘性法則に従わず、せん断速度の変化に応じて粘度が変化します。これらの流体は、せん断減粘性流体、せん断増粘性流体、ビンガム流体に分類できます。

 せん断減粘性流体は擬塑性流体とも呼ばれ、せん断速度が増加すると粘度が低下します。例としては、ラテックス塗料やポリマー溶液が挙げられます。これらは力を受けると流れやすくなるため、ストレス下で容易に広がることが求められる用途で役立ちます。

 一方、せん断増粘性流体は、せん断速度が増加すると粘度が増加します。一般的な例としては、コーンスターチと水の混合物が挙げられます。この混合物は、攪拌すると流動しにくくなり、応力を受けると抵抗が大きくなります。

 ビンガム流体は異なる挙動を示します。特定の降伏応力がかかるまでは固体として機能しますが、その後は流体のように流動します。例としては、歯磨き粉やマヨネーズが挙げられます。これらは初期応力には抵抗しますが、降伏応力を超えると流動し始めます。これらの種類の流体を理解することは、パイプラインから工業プロセスまで、さまざまな流体システムを設計および分析し、効率と適切な機能を確保するために不可欠です。

流体は、ニュートンと非ニュートンの2つの主要なタイプに分類されます。ニュートン流体は一定の粘度を持ち、そのせん断応力は線形です...

Education

JoVE Core

Civil Engineering

土木工学

Unit 1

ユニット1

Fluid Properties

流体の特性

KEY TERMS AND CONCEPTS

主要用語と概念

newtonian vs non-newtonian fluid behavior

Fluids can be grouped by how they respond to shear stress. Shear stress is a force that acts across a material, and shear strain rate describes how quickly it changes shape or flows. In this lesson, fluids are divided into Newtonian and non-Newtonian types.

Newtonian fluids follow Newton’s law of viscosity. Their shear stress changes in a linear way as the shear rate changes. That means their viscosity stays constant, so their flow is predictable and easier to analyze. Water, air, oil, and gasoline are common examples.

Non-Newtonian fluids do not follow Newton’s law of viscosity. Their viscosity changes when the shear rate changes. These fluids are often grouped into shear-thinning, shear-thickening, and Bingham plastics.

Shear-thinning fluids are also called pseudoplastic fluids. Their viscosity decreases as the shear rate increases, so they flow more easily under force. Latex paint and polymer solutions are examples, and this makes them useful when a material needs to spread easily.

Shear-thickening fluids behave in the opposite way. Their viscosity increases as the shear rate increases, so they resist flow more when they are agitated. A cornstarch-water mixture is a common example.

Bingham plastics have another pattern. They act like solids until a certain yield stress is reached. After that, they begin to flow like fluids. Toothpaste and mayonnaise are examples, and they resist initial stress before they start moving.

Knowing these fluid behaviors helps in many real systems. It supports the design and analysis of pipelines and industrial processes. It also helps engineers choose the right fluid for efficient and reliable function.

Newtonian vs Non-Newtonian Fluid Behavior

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types of fluids

Fluids can be grouped by how they respond to shear stress. Shear stress is a force that acts across a material, and shear strain rate describes how quickly it changes shape or flows. In this lesson, fluids are divided into Newtonian and non-Newtonian types. Newtonian fluids follow Newton’s law of viscosity. Their shear stress changes in a linear way as the shear rate changes. That means their viscosity stays constant, so their flow is predictable and easier to analyze. Water, air, oil, and...

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key terms and concepts

Learn how Newtonian and non-Newtonian fluids respond to shear stress, with examples of shear-thinning, shear-thickening, and Bingham plastics.

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civil engineering

Newtonian vs Non-Newtonian Fluid Behavior

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