Industry-relevant training in Business, Technology, and Design to help professionals and graduates upskill for real-world careers.
Fun, engaging games to boost memory, math fluency, typing speed, and English skills—perfect for learners of all ages.
Enroll to start learning
You’ve not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take practice test.
Listen to a student-teacher conversation explaining the topic in a relatable way.
Welcome, everyone! Today, we'll dive into viscous fluid flow. To start, a fluid is defined as a substance that continuously deforms under shear stress. Can anyone explain why this is different from solids?
Solids can resist shear and hold their shape.
Exactly! In fluid mechanics, we categorize substances into fluids and non-fluids. Fluids include gases and liquids, while non-fluids are primarily solids. Remember, understanding this distinction is key!
What are some properties we should know about fluids?
Great question! Fluids have kinematic, transport, and thermodynamic properties. We’ll go through these in detail.
Let's talk about kinematic properties like velocity and acceleration. Who can tell me what vorticity is?
Isn’t it the measure of rotation in a fluid?
Correct! Vorticity indicates how much and how fast the fluid is rotating. Can anyone connect this to real-world applications?
Like in weather systems? Tornadoes and cyclones!
Absolutely! Understanding vorticity helps predict these events. Let's review how we express these properties mathematically.
Now, let’s discuss the material derivative. It tracks the rate of change of a property as it moves with the fluid. Can anyone describe how we mathematically express this?
It involves the total derivative, right? We consider changes over time and space.
Exactly! The substantial derivative combines local and convective changes. Does anyone remember the formula?
It’s dQ/dt = ∂Q/∂t + V · ∇Q.
Spot on! This formula is crucial. Always remember it represents how a fluid property evolves over time and space.
Next, we will explore how fluid elements translate, rotate, and deform. What types of deformation can a fluid element undergo?
Translation, rotation, shear strain, and dilation!
Exactly! Understanding these motions is vital for our upcoming derivations. Let’s visualize a fluid element moving in an xy-plane.
Why is visualizing it important?
It helps to see how changes in one part of the fluid affect others. Let's derive the relationships using our visualization.
To conclude, we’ll summarize our derivation of strain rates and their significance. Why do we need these rates in fluid dynamics?
To understand how fluids behave under different conditions, I guess?
Correct! Strain rates influence our equations of motion, like the Navier-Stokes equation we will derive next. Can anyone recall what those equations represent?
They describe the motion of fluid substances!
Yes! The Navier-Stokes equations are fundamental. Preparing for our next discussions will involve these principles.
Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.
The lecture elaborates on viscous fluid flow, emphasizing the derivation of the Navier-Stokes equation. It reviews the classification of materials into fluids and non-fluids, and explores various kinematic and transport properties of fluids. Key concepts such as material derivatives and fluid element dynamics are introduced to provide a foundational understanding for future discussions.
This lecture delves into the topic of viscous fluid flow, with a particular focus on deriving the Navier-Stokes equation. The instructor notes the importance of hand-derived equations over slide presentations for clarity. Viscous fluids, differentiated from non-fluids (solids), continuously deform under shear forces. The discussion also revisits the classification of matter in fluid mechanics into fluids (gases, liquids) and non-fluids (solids).
Key properties discussed include:
- Kinematic Properties: Velocity, acceleration, vorticity, rate of strain, and angular velocity.
- Transport Properties: Viscosity, thermal conductivity, and mass diffusivity.
- Thermodynamic Properties: Density, pressure, temperature, entropy, and enthalpy.
- Miscellaneous Properties: Surface tension and eddy diffusion coefficients.
The lecture exemplifies the practical application of material and substantial derivatives, leading to a deeper understanding of fluid motions, strain rates, and rotation. The discussion emphasizes the significance of understanding both the local and convective derivatives.
Dive deep into the subject with an immersive audiobook experience.
Signup and Enroll to the course for listening the Audio Book
Welcome students. So, this is the week 10, lecture number 1, here we are going to study about the topic that is mentioned in this slide, this is about viscous fluid flow. Actually, you have, we have gone through this topic before but in a much more crude manner.
The introduction sets the stage for the lecture on viscous fluid flow, indicating that this is a continuation of a topic students have encountered before. However, this time, it will be explored in depth.
Think of it like revisiting a familiar recipe but diving deeper into the cooking techniques. Just like you might have made a cake before, but now you're learning how to perfectly whisk egg whites to achieve that fluffy finish.
Signup and Enroll to the course for listening the Audio Book
The main objective of this module is going to be able to derive Navier Stokes equation from scratch, so how to start from the beginning and derive the Navier Stokes equation.
This chunk outlines the goal of the module, which is to derive the Navier-Stokes equation. This equation is fundamental in fluid mechanics as it describes the motion of viscous fluid substances. Understanding its derivation will provide insights into how fluids behave under various conditions.
Imagine you're trying to understand how a car moves through the air. You need to break down the forces acting on the car, much like you would derive the Navier-Stokes equation to understand fluid motion thoroughly.
Signup and Enroll to the course for listening the Audio Book
We will go very slow in this and we will complete this module in lecture 3 to 4, so now I will minimize this and use this board now.
The lecturer emphasizes a hands-on approach to learning, suggesting that derivation of the Navier-Stokes equations will be done manually rather than relying heavily on slides. This method is believed to enhance understanding for a complex topic like fluid dynamics.
It's like learning to ride a bicycle. Initially, you won't just watch others; you'd get on that bike, feel its balance, and understand how to steer by practicing instead of just watching a video.
Signup and Enroll to the course for listening the Audio Book
In fluid mechanics, a matter is classified into fluids and non-fluids. So, in thermodynamics, the normal definition is classification in solids, liquids and gases.
This chunk clarifies how matter is classified differently in fluid mechanics compared to thermodynamics. In fluid mechanics, the focus is on fluids (which include liquids and gases) versus non-fluids, primarily solids. This distinction is crucial for understanding the behaviors of materials under different forces.
Think of a crowd at a concert: the crowd fluidly moves as a whole (fluids), while the solid structures of the concert stage or the ground (non-fluids) don’t move with the crowd.
Signup and Enroll to the course for listening the Audio Book
Another basic revision is properties of fluid, so first is kinematic property, that is, velocity, acceleration, vorticity, rate of strain, angular velocity etc.
This segment introduces various properties of fluids, starting with kinematic properties. These are characteristics that describe the motion of fluids without considering the forces acting upon them, including parameters like velocity and acceleration.
Consider how you track the speed of a car (velocity) as it goes around a bend. The car's speed and path are like the fluid’s kinematic properties.
Signup and Enroll to the course for listening the Audio Book
There are many other properties like this kinematic. Transport properties, you know, are viscosity, thermal conductivity, mass diffusivity.
Transport properties help understand how fluids respond to external stimuli. For instance, viscosity measures a fluid's resistance to flow, which affects how it behaves in different scenarios, such as flowing through pipes or over surfaces.
Think of syrup versus water. Syrup is more viscous, meaning it flows slowly compared to water. This unique property illustrates how transport properties affect fluid behavior in real-world applications.
Signup and Enroll to the course for listening the Audio Book
There are some other miscellaneous properties. Miscellaneous properties includes surface tension, it is important to know these properties, at least know what those are vapour, pressure.
Miscellaneous properties such as surface tension and vapor pressure play critical roles in fluid behaviors. Surface tension, for example, explains why some insects can walk on water while vapor pressure is crucial in understanding boiling and evaporation.
Imagine how a water droplet forms on a leaf due to surface tension. That phenomenon showcases how unique properties of fluids affect everyday experiences.
Signup and Enroll to the course for listening the Audio Book
Now we go into little bit more detail in kinematic properties.
This transition indicates a deeper examination of kinematic properties, where terms such as velocity, strain rates, and angular velocity will be discussed. These concepts are essential for analyzing fluid motion mathematically.
Consider how a soccer ball travels through the air. By analyzing its velocity and how it changes direction (angular velocity), we can better understand the fluid dynamics surrounding it.
Signup and Enroll to the course for listening the Audio Book
So, the idea of this particular lecture today is that we are going to write what actually material derivatives are and we see the rotation you know how the fluid particle gets rotated and try to obtain the strain rates.
This section introduces material or substantial derivatives, defining how they quantify changes in fluid properties for individual particles moving through a flow field. This concept is vital for understanding how fluids change over time and space.
Imagine a leaf floating on a stream. The material derivative helps analyze how the leaf's position and state change as it moves with the water.
Signup and Enroll to the course for listening the Audio Book
A fluid element can undergo the following 4 types of motion or deformation: translation, rotation, extensional strain or dilation, and shear strain.
The basic types of motion a fluid can experience include translation (moving from one location to another), rotation (spinning), extensional strain (stretching), and shear strain (sliding). Each of these motions influences how fluid flows and behaves under different conditions.
Think of a dance performance; the dancers may move across the stage (translation), spin (rotation), stretch into formations (extensional strain), or slide past each other (shear strain), analogous to the movements of fluid particles.
Signup and Enroll to the course for listening the Audio Book
So, we are going to derive the strain rates, so one thing I would like to take your attention to, is this figure.
Here, the focus is on deriving strain rates from fluid deformation. The process involves analyzing how the shape of a fluid element changes during motion, which is crucial for predicting fluid behavior under various stresses.
Picture dough being kneaded; as you stretch and fold it, the strain rates inform you how much the dough's shape is changing. Likewise, fluid elements undergo similar transformations under motion.
Signup and Enroll to the course for listening the Audio Book
With reference to the above figure, we can observe the following transformations, I mean, of transformation or deformation in the fluid element within the time interval of t + dt.
This segment emphasizes the observation of a fluid element over a time interval, noting how different points within the fluid move relative to each other. Understanding these transformations helps in analyzing fluid flow and the resulting stresses.
Imagine capturing a video of a balloon being inflated. Watching the points on the balloon's surface move as it expands is akin to tracking transformations of a fluid element over time.
Learn essential terms and foundational ideas that form the basis of the topic.
Key Concepts
Viscous Fluid: Fluid that deforms continuously under shear.
Kinematic Properties: Properties related to velocity, acceleration.
Material Derivative: Indicates change of fluid property with movement.
Strain Rate: Rate of deformation in fluid elements.
See how the concepts apply in real-world scenarios to understand their practical implications.
A river flowing smoothly is an example of viscous fluid flow.
Air flow over an airplane wing demonstrates the importance of understanding kinematic properties.
Use mnemonics, acronyms, or visual cues to help remember key information more easily.
Fluid flows and bends, under shearing hands, it takes many shapes, as the motion expands.
Imagine a river where the water bends smoothly around rocks; it's like how fluids deform gently under pressure.
Remember KAV: Kinematic, Acceleration, Velocity for fluid properties!
Review key concepts with flashcards.
Review the Definitions for terms.
Term: Viscous Fluid
Definition:
A fluid that deforms continuously under shear stress.
Term: Kinematic Property
Definition:
Properties relating to the motion of fluids, like velocity and acceleration.
Term: Material Derivative
Definition:
A derivative that expresses the rate of change of a quantity as it moves with the flow.
Term: Substantial Derivative
Definition:
Another term for the material derivative; indicates changes in fluid properties over time and space.
Term: Strain Rate
Definition:
The rate at which deformation occurs in a fluid element.