#%CC%81Navier-Stokes

Rod2ik 🇪🇺 🇨🇵 🇪🇸 🇺🇦 🇨🇦 🇩🇰 🇬🇱 ☮🕊️rod2ik.bsky.social@bsky.brid.gy
2025-09-20

Une #IA #AI de #Google résout un #problème #mathématique réputé #impossible Une nouvelle #famille de #singularités des équations de #́Navier-Stokes a émergé, confirmée ensuite par des #mathématiciens de #NewYork #University et #Stanford. L' #IA devient co-auteur www.cointribune.com/une-ia-de-go...

IA : Google DeepMind franchit ...

Scott Rochesterscottrochester
2025-09-17

17 Sep 'What is your SC wrong about? '

HayWire thinks that Fluid Dynamics is easy.

see Alt Text for more

Composite image

LHS

A colour pencil drawing of a headshot of an 18 year old young man - he has fly away blonde hair and blue eyes - in this relaxed pose he has a thoughtful and neutral expression - he is wearing a white T shirt against a yellow background - the image is labelled HayWire

RHS

Book extract

SlenderWolf Conflicts and Alliances

Chapter 17
The Inventors Club

“We don’t use any of it as a component in a process. Fluid dynamics is a challenging subject. I know it, but Tom and Jerry don’t. Anyway, we don’t need complexity.”

HayWire joins in, “fluid dynamics is fine, I don’t know why everybody gets so het up about it, even my GuildMaster! I know it’s difficult for some people, but I don’t understand why!”

BarmyWaffle is surprised, “where did you learn fluid dynamics? They don’t teach it in schools. They did that at universities in the old days.”

Excited, HayWire wants to launch into a detailed discussion, “my maths teacher! He spent extra time with me outside regular lessons, taught me calculus, and then I started reading more. I asked him about Navier-Stokes equations. He only half knew it, so we studied it together. Best teacher I ever had!”

“You understand non-linear partial differential equations?”

“Theoretically, yes, never used them in practice!”

“I have no idea what you two are talking about,” says NutJob, “and I thought I knew a thing or two about maths.”

The novel is scheduled for publication in late 2025

copyright © Scott Rochester 2025
Pustam | पुस्तम | পুস্তম🇳🇵pustam_egr@mathstodon.xyz
2025-08-24

Basics of Numerical Weather Prediction (NWP):

1. THE HORIZONTAL MOMENTUM EQUATION:
\[
\frac{d\mathbf{V}}{dt} + f\hat{k} \times \mathbf{V} = -\nabla \phi + \frac{\sigma}{p_s} \frac{\partial \phi}{\partial \sigma} \nabla p_s + \mathbf{F}
\]

2. THE CONTINUITY EQUATION:
\[
\frac{\partial p_s}{\partial t} + \nabla \cdot (p_s \mathbf{V}) + \frac{\partial}{\partial \sigma}(p_s \dot{\sigma}) = 0
\]

3. THE THERMODYNAMIC ENERGY EQUATION:
\[
\frac{1}{R} \frac{d}{dt} \left[ \sigma \frac{\partial \phi}{\partial \sigma} \right] + \frac{RT}{C_p p} \left[ p_s \dot{\sigma} + \sigma\dot{p_s} \right] = -Q
\]

4. HYDROSTATIC EQUATION:
\[
\frac{\partial \phi}{\partial \sigma} = -\frac{RT_v}{\sigma}
\]

5. SURFACE PRESSURE TENDENCY EQUATION:
\[\displaystyle
\frac{\partial p_s}{\partial t} = -\int_{0}^{1} \nabla\cdot (p_s \mathbf{V}) \, d\sigma
\]

6. MOISTURE EQUATION:
\[\displaystyle
\frac{\partial}{\partial t} (p_s q) + \nabla\cdot (p_s q \mathbf{V}) + \frac{\partial}{\partial \sigma} (p_s q \dot{\sigma}) = p_s S
\]

The six primary unknowns are: \(\mathbf{V}\) (horizontal wind velocity), \(p_s\) (surface pressure), \(T\) (temperature), \(q\) (specific humidity or moisture), \(\phi\) (geopotential), and \(\dot{\sigma}\) (sigma velocity or vertical velocity in \(\sigma\)-coordinates).

#NWP #Weather #NumericalWeatherPrediction #Meteorology #Climate #ClimateScience #Earth #EarthScience #ClimateChange #ClimateSciences #Science #WeatherPrediction #Humidity #Moisture #Pressure #Velocity #SurfacePressure #HydrostaticEquation #WeatherPrediction #Ocean #Atmosphere #AOS #ClimateDynamics #WeatherDynamics #Geopotential #SigmaVelocity #VerticalVelocity #MoistureEquation #Thermodynamics #Dynamics #NavierStokes

Pustam | पुस्तम | পুস্তম🇳🇵pustam_egr@mathstodon.xyz
2025-07-01
trndgtr.comtrndgtr
2025-06-17

The Secret Order of Pi - Terence Tao on Lex Fridman

trndgtr.comtrndgtr
2025-06-16

Blow-Up or Not? - Terence Tao on Lex Fridman

🌊 Scientists have advanced in understanding turbulence, a long-standing puzzle for physicists. This progress aids in solving the Navier–Stokes equations, a major challenge in math and physics, and a Millennium Prize Problem by the Clay Mathematics Institute. Recent developments are crucial for fluid dynamics, impacting engineering, meteorology, and more.

@goodnews

#GoodNews #Physics #Turbulence #NavierStokes #ScienceBreakthrough
edition.cnn.com/2025/02/06/sci

2025-04-15

Researchers claim to have solved Hilbert’s sixth problem by unifying three theories of #FluidDynamics at different levels of granularity:

+ Newton’s laws of motion at the microscopic level where fluids are composed of particles - little billiard balls bopping around and occasionally colliding

+ The Boltzmann equation at the mesoscopic level where the equation considers the likely behavior of a typical particle

+ Euler and #NavierStokes equations at the macroscopic level where the fluids are a single continuous substance

scientificamerican.com/article

Preprint arxiv.org/abs/2503.01800

Pustam | पुस्तम | পুস্তম🇳🇵pustam_egr@mathstodon.xyz
2025-03-12

An Article in the Annual Review of Condensed Matter Physics on Turbulence by KR Sreenivasan and J Schumacher
annualreviews.org/content/jour

What is the turbulence problem, and when can we say it’s solved? 🌪️ This deep dive by Sreenivasan & Schumacher explores the math, physics, and engineering challenges of turbulence—from Navier-Stokes equations to intermittency and beyond. A must-read for anyone fascinated by chaos, complexity, and the unsolved mysteries of fluid dynamics! 🌀

A summary of the talk presented by KR Sreenivasan in December 2023 at the International Center for Theoretical Sciences (ICTS-TIFR) in Bengaluru, as part of a program on field theory and turbulence.
youtube.com/watch?v=fwVSBYh-KC

"Field Theory and Turbulence" program link: icts.res.in/discussion-meeting

#FluidDynamics #Physics #NavierStokes #UnsolvedMystery #Mechanics #Dynamics #FluidMechanics #Science #Chaos #TurbulentMotion #Randomness #Chaotic #Fluid #ClassicalMechanics
#Turbulence

Only a genderfluid creature can hope to solve the Navier-Stokes Equations existence and uniqueness problem.

#NavierStokes #genderfluid

2025-02-25

So, I mentioned already that we cannot really model #lava flows. The main reasons for that is that we don't actually know how lava behaves, at least not in sufficient detail.

Of course, lava is a fluid, and a (very) viscous one at that, so we know that it follows the Navier–Stokes equations. We also know that its behavior is heavily dependent on temperature, so we know that we also need the heat equation, with both kinds of boundary conditions (conduction to ground, and radiation on the free surface).

And that's all we know. Seriously.

OK, not really, but everything else is extremely uncertain. When modeling a viscous fluid (like lava, or any other geophysical flow for the matter), the first thing you need to know is what the viscosity is. And for lava, we don't know. There's a lot of things we do know, but not enough.
For example, we know that the viscosity depends on temperature, chemical composition, degree of crystalization, amount and types of volatiles in the melt, and so on and so forth. But we don't exactly know the laws relating the viscosity to all of these chemical and physical properties.

2/

#NavierStokes #NavierStokesEquations

2024-12-10

Tutti i libri di critica alla specializzazione dell'istruzione e la perdita di capacità necessarie per il mantenimento della propria vita senza deleghe si potrebbero tranquillamente sostituire con una registrazione dei cinque minuti di telefonata in cui l'idraulico mi ha spiegato come far tornare l'acqua calda #navierstokes

2024-12-06

So there's apparently a #metal song mentioning the #NavierStokes equations now.

youtu.be/Jy99ywCp3qU

#music #CFD #meteorology #parody

Chapel Programming Languagechapelprogramminglanguage
2024-11-15

In the concluding article of his "Navier-Stokes in Chapel" series, Jeremiah Corrado demonstrates how a Chapel program with size and complexity like Python performs and scales competitively with a more complex C++/MPI/OpenMP port.

chapel-lang.org/blog/posts/bns

Thanks to the @labarba group for creating and maintaining the CFD Python tutorials upon which this series was based! lorenabarba.com/blog/cfd-pytho

Screen shot of the linked blog articleA quiver flow plot and pressure gradient. These images are the results of running a fluid dynamics simulation written in Chapel.A graph comparing the time to run the Chapel and C++ versions as the number of nodes is increased. The Chapel version is competitive with the C++ version and it's actually faster for the larger problem size.
Chapel Programming Languagechapelprogramminglanguage
2024-10-29

In his latest article studying Navier-Stokes computations in Chapel, Jeremiah Corrado demonstrates how a 4-line change turns the multicore version from his previous article into a distributed, scalable computation.

Read all about it here: chapel-lang.org/blog/posts/bns

Based on Step 9 of "12 Steps to Navier-Stokes" from @labarba.

Chapel Programming Languagechapelprogramminglanguage
2024-07-10

We’ve just published the second in Jeremiah Corrado’s series of blog posts in which he translates key steps of the Lorena A. Barba group’s great “12 steps to Navier-Stokes” series into Chapel, demonstrating the parallel performance that can be achieved.

chapel-lang.org/blog/posts/bns

Chapel Programming Languagechapelprogramminglanguage
2024-04-11

Dive into the world of fluid dynamics and discover the power of the Chapel programming language in scientific computing applications in our latest blog post, 'Navier-Stokes in Chapel'!

Check it out: chapel-lang.org/blog/posts/bns

2024-04-11

One of my colleagues recently created a #blog post that introduces #NavierStokes simulation with #chapelLang. I particularly appreciated the gentle introduction to computational fluid dynamics. It ports #python code and makes one simple change to make the simulation run #multicore!

chapel-lang.org/blog/posts/bns

#science #hpc

Cassidy Curtisotherthings
2024-02-14

These fluid sim bugs ain't gonna fix themselves.

Cassidy Curtisotherthings
2024-02-13

I'm midway through a (major, long overdue) overhaul of the fluid transport layer of my watercolor simulation. Made some good progress over the weekend. But more importantly: I made lots of new bugs. Glorious, unrepentant, face-eating bugs. I almost don't have the heart to squash them.

vimeo.com/cassidy/big-wet-pixe

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