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

Os fluidos são classificados em dois tipos principais: newtonianos e não newtonianos. Os fluidos newtonianos têm uma viscosidade constante e sua tensão de cisalhamento está linearmente relacionada à taxa de deformação de cisalhamento.
O comportamento dos fluidos newtonianos é previsível. Exemplos incluem água, ar, óleo e gasolina.
Fluidos não newtonianos, no entanto, exibem viscosidade variável com base na taxa de cisalhamento. Eles são divididos em plásticos de cisalhamento, espessamento de cisalhamento e plásticos Bingham.
Fluidos de afinamento de cisalhamento, como tinta látex e soluções de polímero, mostram viscosidade aparente diminuída com uma taxa de cisalhamento aumentada, permitindo que fluam mais facilmente quando cortados.
Esta propriedade é útil em aplicações como pintura com pincel e impressão a jato de tinta, onde é necessária uma aplicação suave e uniforme.
Fluidos de espessamento de cisalhamento, como amido de milho em água, apresentam aumento da viscosidade aparente sob taxas de cisalhamento mais altas e tornam-se mais resistentes ao fluxo quando agitados.
Esta propriedade única os torna úteis em equipamentos de proteção e dispositivos de amortecimento.
Os plásticos Bingham, como pasta de dente e maionese, se comportam como sólidos quando o estresse de escoamento é excedido e, em seguida, fluem como fluidos, tornando-os ideais para produtos que precisam de extrusão ou espalhamento.

tipos de fluidos

Types of Fluids

Os fluidos podem ser classificados em fluidos newtonianos e não newtonianos com base em sua resposta à tensão de cisalhamento. Os fluidos newtonianos têm uma relação linear entre a tensão de cisalhamento e a taxa de deformação de cisalhamento, seguindo a lei da viscosidade de Newton. Sua viscosidade permanece constante independentemente da taxa de cisalhamento, tornando seu comportamento previsível e mais fácil de analisar. Exemplos comuns incluem água, ar, óleo e gasolina.

Em contraste, os fluidos não newtonianos não seguem a lei da viscosidade de Newton, e sua viscosidade muda com taxas de cisalhamento variáveis. Esses fluidos podem ser divididos em plásticos de afinamento por cisalhamento, espessamento por cisalhamento e Bingham.

Os fluidos de afinamento por cisalhamento, também conhecidos como fluidos pseudoplásticos, diminuem a viscosidade com uma taxa de cisalhamento crescente. Exemplos incluem tinta látex e soluções de polímero, que fluem mais facilmente quando submetidas à força, tornando-as úteis em aplicações que exigem fácil espalhamento sob estresse.

Os fluidos de espessamento por cisalhamento, por outro lado, aumentam a viscosidade com uma taxa de cisalhamento crescente. Um exemplo comum é uma mistura de amido de milho e água, que se torna mais resistente ao fluxo quando agitada, proporcionando maior resistência sob estresse.

Os plásticos Bingham apresentam um comportamento diferente; eles agem como sólidos até que uma tensão de escoamento específica seja aplicada, após o que fluem como fluidos. Exemplos incluem pasta de dente e maionese, que resistem ao estresse inicial, mas começam a fluir quando a tensão de escoamento é superada. Entender esses tipos de fluidos é crucial para projetar e analisar vários sistemas de fluidos, de tubulações a processos industriais, garantindo eficiência e funcionalidade adequada.

Tipos de fluidos

Os fluidos são classificados em dois tipos principais: newtonianos e não newtonianos. Os fluidos newtonianos têm uma viscosidade constante e sua tensão de cisalhamento é linearmente ...

Education

JoVE Core

Civil Engineering

Engenharia Civil

Unit 1

Unidade 1

Fluid Properties

Propriedades dos Fluidos

KEY TERMS AND CONCEPTS

TERMOS E CONCEITOS-CHAVE

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.

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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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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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