Ally Miley

Found last week demotivating- I decided to leave all the practice problems for the end of the chapter, which was not a good idea. I’ve learned that going forward, it’s essential to integrate the practice problems into the reading.

The happy desk chaos resulting from mashing these things into my brain

That marks the end of my learnings thread! It's felt really helpful to condense my notes into bite-size takeaways, and although many of these words are not my own (stress tensor? shear force?), putting these concepts into my own phrasings will hopefully help them stick around.

Normal Pressure: Pressure arising from when an exerted force acts on a boundary surface
Shear Force: Stresses due to viscosity, due to a force exerting parallel to a boundary surface

The Kronecker Delta also ensures that normal pressure is only applied for stresses arising from normal pressure and not stresses due to viscosity.

The Kronecker Delta comes in handy for a couple things:
Multiplying negative fluid pressure by the Kronecker Delta allows us to evaluate stresses in the different directions, as well as the shear force acting on a surface along another direction.

This all comes together to describe what forces are acting on in a fluid, and how forces are distributed inside a fluid via stress tensor calculation, adding viscous shear stress to the product of negative fluid pressure and the Kronecker Delta.

Viscosity varies by fluid and temperature, and can be calculated if kinematic viscosity and density are known. But I'm actually not sure in what scenarios kinematic viscosity would be known and not dynamic viscosity.

The derivative of the velocity distribution gives the velocity gradient, or the shear strain rate (how fast are neighboring fluids sliding past each other).
Shear strain rate increases in linearly with shear stress, precisely: shear stress = fluid viscosity * shear strain rate in Newtonian fluids.

Fluid velocity within a bounded arena varies by proximity to the boundaries and the force source (some external source). At the solid boundary, fluid velocity is zero relative to the boundary (known as: no slip condition).

What I thought was really fun was getting into viscosity (give me something to integrate/differentiate and a diagram), and describing how forces are distributed inside a fluid.

A chain below of the major highlights re: Viscosity😎

I've had a fulfilling time this last week going through the first sections of @mitocw.bsky.social's Engineering Mechanics II and learning the basics about how fluid behavior is described (thinking about the basics like mass, weight, volume, temperature). 🤓

Which I'm sure will further reinforce his belief that water can indeed be wet. I'm hoping I'll learn that water can exist in varying levels of wetness depending on the environment surrounding the water molecule.

Covering absolute basics of fluid mechanics - sheering stress and rate of sheering strain, viscosity. The topics are reminding me of an old debate I used to have with my younger brother - Is water wet?
After brief Google searching, I'm seeing there's a topic I'm soon to run into - 'wetting'

Thank you for the offer of help, I will definitely reach out.
WOW, that's interesting and important work! I would love to hear about your experience during that time.

There are so many problems to tackle related to climate change, I'm fired up to come to greater understand more of them.

To be clear: I was a calculus lover from the get-go, but my experience with algebra based physics was quite frustrating, so I'm thrilled with getting to move into what makes much more sense to my brain, calculus based physics.

re: readings time
I haven't thought deeply about things like calculating velocity, acceleration, force, derivatives etc in about a decade 😳 BUT I'm finding that it's all coming back with an ease that surprises me! And unlike my previous go with this sort of material, I'm actually enjoying this :)

The recommended text is not anything I can find without ordering via Amazon (a no-go for me), which makes sense as the course is from 2006 and the text from 1996, but I'm giving it a go using the 5th edition rather than the 3rd.

I'm taking my time with the readings.

The major topics I'm tackling:
-Fluid Mechanics (eek)
-Fundamentals of Sustainable Engineering
-Environmental Engineering
-Fundamentals of Hydrology (major stretch)

I'm using MIT OpenCourseWare's 'Engineering Mechanics II' to guide my foray into Fluid Mechanics.

Excited to join Bluesky!

My initial intent in joining is to document my journey in discovering the fundamentals of environmental engineering over the next half year or so. I've talked to a few experts about how to get started, and with their advice have developed a course plan.