Chris Johnson

Reader in Nonlinear Dynamics at the University of Manchester. Interested in a wide range of granular and fluid flows.

[Chris Johnson @grainsandfluids]

@UoMpodcast Is there a problem with permissions on the podcasting system? My teaching videos (embedded) now show a permission error, and when logged into https://t.co/pVPkG91K2j I get the following when trying to watch my own videos (while logged in)

[Chris Johnson @grainsandfluids]

@oeskildjensen Really beautiful paper. I was reminded in several places of @amandaghassaei 's amazing digital marbling simulations ( https://t.co/DvO1b0MNOr ) - the equations being solved are different, but not completely unrelated I think.

[Chris Johnson @grainsandfluids]

@mpaldridge I think ⁴⁺⁴⁺⁴⁺³ / ₈ is allowed, though that may be too specific, given other rhythms in the melody

[Chris Johnson @grainsandfluids]

@mpaldridge I'd maybe say 3/2 not 6/4 - it feels like simple not compound time.

[Chris Johnson @grainsandfluids]

Four years after this visit, the 'future developments' have come to fruition and are published in JGR Atmospheres — "Modelling Wind-blown Umbrella Clouds in Lagrangian Dispersion Models" https://t.co/t0GqihO1Br , led by my student @frank_millward . @MetOffice_Sci @UoMSciEng

[Chris Johnson @grainsandfluids]

Just returned from a great few days at the @metoffice_sci learning about their atmospheric dispersion modelling and discussing future developments, as part of the @NERCscience 'V-PLUS' project. Many thanks to @claireswitham and the rest of the ADAQ team for their hospitality.

[Chris Johnson @grainsandfluids]

Postdoc position in debris flow dynamics available at Manchester - details at https://t.co/RCMOD8kwxX , application deadline 31st August. This project combines modelling, field observations at Illgraben, and small-scale lab experiments — something for everyone!

[Chris Johnson @grainsandfluids]

@mpaldridge I think the short answer is no, not many. Gell-Man–Low theorem and Barndorff-Nielsen–Shephard model are two others, but neither sprang to mind...

[Chris Johnson @grainsandfluids]

@mpaldridge I think my take on this is similar to the Oxford comma: comma iff any of the items contains 'and'; en-dash iff any of the names is double-barrelled.

[Chris Johnson @grainsandfluids]

@WadsworthFabian @LMU_Volc (+ gravity, of course...)

[Chris Johnson @grainsandfluids]

@WadsworthFabian @LMU_Volc What equation is the analytical solution for? m dv/dt = - Cd A v|v| ? Or something more complex?

[Nick Higham @nhigham]

Lecturer in Applied Mathematics position open at @OfficialUoM closing March 30, 2023 https://t.co/UgBSeODyA2

[Pouria Hadjibagheri MBE @Pouriaaa]

I am incredibly grateful for this article by @FraserNelson. I couldn't agree more with the underlying premise.

Our dream team, led by @statsgeekclare, wanted to serve. We all want to do more. We just need opportunity and support to do a lot more.

https://t.co/9CqOJvkfNZ

[Chris Johnson @grainsandfluids]

@mpaldridge I'd actually notate this as a metric modulation (<crotchet>=<dotted crotchet>) rather than tempo change at your 3/4 bar. The tempi don't quite work perfectly (82bpm to 126bpm in the recording is a factor of 1.53 not 1.5), but I suspect ×1.5 was intended.

[Chris Johnson @grainsandfluids]

@mpaldridge I don't think that's a defence, because the notes in question (green=yours, red=theirs) don't cross a change in tempo. Their version would imply that there is a steady triplet beat from their first 2/4 bar up to their 𝅘𝅥 =125, which is not true...

[Chris Johnson @grainsandfluids]

Now advertised: postdoc in debris flow dynamics at the University of Manchester https://t.co/HIebkWQ8Sq
Closing date 31st January. Please pass on to any potential candidates!

[Chris Johnson @grainsandfluids]

🚨Postdoc available! A three-year @NERCscience funded postdoc on modelling debris flow dynamics will be available at the University of Manchester @UoMSciEng, starting early 2023.

⭐️Please RT and pass on this early announcement to potential candidates. DM/email me for details.

[Detlef Lohse @detlef_lohse]

#EFMC14: Anne Juel from Manchester, giving her plenary lecture on instabilities and pattern formation in viscous fingering: A fresh dynamical system theory view on a classical problem and variations thereof (elastic walls, modified cross-sections).

[Chris Johnson @grainsandfluids]

@SlowCheetah19 @ecpbrear Here's the names:

[Chris Johnson @grainsandfluids]

@nbehera2022 I'll post the job advertisement on twitter when it comes out, or email me if you'd like more information

[Chris Johnson @grainsandfluids]

@davepetley FYI, we've just had a project funded on modelling exactly this type of debris flow, focusing on surge waves at Illgraben. Postdoc announcement at https://t.co/OVeMj2X2Lk

[Chris Johnson @grainsandfluids]

🚨Postdoc available! A three-year @NERCscience funded postdoc on modelling debris flow dynamics will be available at the University of Manchester @UoMSciEng, starting early 2023.

⭐️Please RT and pass on this early announcement to potential candidates. DM/email me for details.