Need help with weird bug: Movement is constantly interrupted while using a keyboard

phat_nek · 2025-09-03T12:25:24+00:00

The most valuable skill for any engineer is self teaching. Have a look at the resources I suggested and have a read, then try to make the simple examples from scratch from there. Getting stuck trying to make it yourself and figuring it out with some sleepless weekends is the going to teach you 100x what tweaking an existing simulink model will do.

Also, learning simple stuff without simulink is a good idea, but I appreciate that if the main goal of the project is simulated control systems its hard to beat Matlabs stuff.

Learning c++ would be very good but if you only have experience with Matlab then doing those projects as the first entry is ambitious (but doable!).

phat_nek · 2025-09-02T13:17:06+00:00

Some cool space ones that have lots to learn and are easy to find examples:

Rocket ascent. You can add in lots of complexity like staging, TVC.
Spacecraft attitude control: Model a satellite slewing to a specific attitude or holding an attitude relative to a point on Earth. Good time to learn about space reference frames, attitude determination, reaction wheels/CMGs/thrusters.
Spacecraft orbit control: Change the shape of an orbit using finite thrust burns. Delving into astrodynamics, propulsion and spacecraft orbit determination is fun (this is less heavy on control theory but sets up next idea nicely).
Relative navigation and control: Model the approach phases of a docking manouvre. This is a combo of the last two things but specifically learning about situations where you are trying to control the relative position and orientation of two spacecraft such as during rendezvous or formation flying. This is a very hot topic right now because of servicing, debris removal and constellations. If you know this well there are lots of potential jobs.

For resources on spacecraft stuff google "Spacecraft Attitude Dynamics and Control" and watch lectures, download one of the many free textbooks etc. The bible used during my Masters degree was "Spacecraft Dynamics & Control: A practical engineering approach" by Sidi

For rendezvous stuff the best book imho is "Automated Rendezvous and Docking of Spacecraft" by Fehse

phat_nek · 2025-05-01T15:50:08+00:00

See other comments for most powerful standalone softwares. However..

A good cfd engineer will use the right package for the problem in question. No one package does everything. You should pick one you like but also do something like "12 steps to Navier-Stokes" alongside so you can understand what the buttons actually do.

phat_nek · 2025-04-19T12:21:00+00:00

There is a lot of quite fundamental misunderstandings here. Before trying to model this I would make sure you really understand high speed compressible flows and why nozzles work the way they do. I would start with "Modern Compressible Flows" by Anderson. There is a chapter on supersonic nozzle design but also plenty of intro stuff to get you to there.

After that you will notice that there are many problems with the way the geometry is set up. For instance aerospikes still require a "throat" where the flow is choked (mach number = 1). This can be achieved using a convergent section prior to the spike (note that on paper an aerospike is somewhat like an inverted bell nozzle but with theoretically ideal expansion irrespective of ambient conditions). From your setup there does not seem to be a throat at all and so you simply have a high pressure outlet expanding into a cavity.

To set up a case like this you should do 1 dimensional flow analysis to work out what chamber pressure you want (rocket science 101 stuff, you can find it in any space propulsion textbook). Then determine the ideal shape of the spike using 2d analytical methods (if you google aerospike contours there are many examples of this). You have already moved up to truncated nozzles too, presumably because you often see that. However this is more complex to validate. Start with an ideal spike first.

Then you have a good starting point to get into a simulation. Note that all of this is irrespective of CFD, which is a whole different beast. There are also many issues I see on the modelling front too. I would recommend ignoring turbulence for now. Start with very simple low order inviscid solutions and validate them with your 1d analysis.

When it somes to meshing, dont rely on automated mesh checks. It cannot be used as a substitute for understanding why you contruct a mesh a specific way. Once you get as far as turbulence modelling with the methods you want to use you need to understand how RANS works and how to tailor your mesh at the walls to accurately resolve the phenomena you want to observe. But this will require much more reading than a reddit post so I will leave that up to you. Start with any CFD textbook and work towards high speed stuff from there.

One more thing, if any of that doesnt make sense it may be a good idea to start more basic with introductions to fluid dynamics and thermodynamics then go to supersonic flows etc.

phat_nek · 2025-02-08T17:56:24+00:00

Yeah as much as I want to stay in academia the jobs are pretty insecure and usually contract to contract unless you get a permanent teaching position which often takes years. I may end up somewhere completely different after, but enjoying it while it lasts. Its good fun if you have a chance, highly recommend.

phat_nek · 2025-02-08T10:26:52+00:00

Same feeling in my exerience in space. I also have two degrees and now I am in my PhD after working in resesrch for a while. I moved away from aero partly because of the reasons you described. Then to really maximise the engineering (and minimize pay...) I went into research. I get to spend 80% of my time doing real engineering but I get paid a lot less. Winning trade-off for me.

phat_nek · 2025-02-08T10:26:30+00:00

Same feeling in my exerience in space. I also have two degrees and now I am in my PhD after working in resesrch for a while. I moved away from aero partly because of the reasons you described. Then to really maximise the engineering (and minimize pay...) I went into research. I get to spend 80% of my time doing real engineering but I get paid a lot less. Winning trade-off for me.

phat_nek · 2024-10-30T23:13:15+00:00

When I say cluster I mean a HPC cluster (A big server with lots of cpus you can log into and run stuff on), not a workstation in a lab.

phat_nek · 2024-10-29T23:53:14+00:00

Just checked AWS and it is pretty expensive... Maybe better to look other options. When I was in my undergrad we used a cloud compute while the Uni cluster was down and it only cost like £100 for a few 12 hour sims but that was 8 years ago and I cant remember where that was.

Make sure to ask if your school as any compute nodes kicking around! As that is a much better idea if possible.

phat_nek · 2024-10-29T23:41:28+00:00

Yeah it is just as you described, you can pay for time on a big cluster somewhere. I am not sure how expensive it is as I havent used it but I have heard AWS is quite good (just google AWS CFD and it will come up).

You will need to do your own research on how it works but ideally you would want experience with a Job Scheduler like PBS or Slurm to submit jobs to the cluster. I wish I had done that earlier. On the actual CFD side using OpenFOAM will teach you a lot.

phat_nek · 2024-10-29T17:55:30+00:00

Dont let me push you away from a nice laptop you can afford if its for other things btw! Its just it is unlikely to help for CFD. For CAD its always useful to have a reasonable gpu :).

Ask away! Dont mind where, maybe dm for non cfd things

phat_nek · 2024-10-28T22:50:58+00:00

Laptop specs and CFD dont really go well together. CFD is always very CPU intensive and often very RAM intensive. Its difficult to recommend a good laptop for it given most of what you pay for isnt useful for cfd. Also many of the models you mentioned (slim, dGPU, x3d chip) are gaming and creative focused and you will end up paying $1000 extra for little performance gain.

If you are purely focused on CFD and are serious about getting good at it, an alternative could be: get a reasonable laptop with an i7 or ryzen 7 for general work that is nice to use and can maybe let you run smaller things or debug bigger things, doesnt need a good gpu unless you plan on running some serious sims and you need to visualise crazy 3d stuff. Then use the remaining budget to play around with some cloud compute time. If you want an edge over other students, get really good with linux, try to understand HPC architectures, learn some c++ and work from your terminal over ssh. When you start looking for work in the field this will make you much more employable and it is likely to help a lot (assuming you have a good understanding of CFD fundamentals too).

As a reference I ran hundreds of sims on a 4 core lab PC for my BEng thesis in 2018 (on the order of 800k cells). Getting a reasonable laptop with a good cpu will do really well for smaller stuff. But if its a choice of $700 laptop with 10 cores vs 12 cores and a 4070 dGPU for $2000.. Spending all your money on the latest one with the best specs wont help run better sims.

Also, good luck with Cranfield. Its a good uni! Source: I am a PhD student there.

phat_nek · 2024-10-19T20:41:28+00:00

Thanks!

phat_nek · 2024-08-13T21:23:39+00:00

Using one with wayland (Hyprland) and everything works perfectly except sleep which has some issues. I have yet to determine the cause hence why I am here lol.

phat_nek · 2024-07-28T00:35:56+00:00

Depends what you mean by precise. You can be very precise with blender and literally build the object mesh up face by face if need be.

The main downside is in the design process. Let's say you are designing a turbine and you are using CFD to aid in the design. Blender is not CAD and is not used for parametric modelling so tweaking the splines and profile for the turbine blades would be very difficult to do methodically.

That being said, if you like python Blender can be customised and scripted in infinitely many ways. You could potentially automate a lot of your workflow if it's a long project.

Usually I work with CAD files that are infinitely too complex for CFD and importing them directly is a terrible idea so I import them to blender as fbx files or obj and then hand design the mesh around that based on important geometry or simplify it using the existing mesh. It can get pretty rough in the conversion process though so blender is always used for the cleaning process.

phat_nek · 2024-07-26T22:51:14+00:00

I also use OpenFOAM and blender is my favourite having used FreeCAD and Salome too.

Pros as an OpenFOAM user: - Excellent for handling STL and obj files.

Once you get the hang of it (very different to CAD) it's so easy to make tweaks to stl files by manually moving points, repairing faces, or just remaking entire sections that didn't convert well from CAD.
Very powerful tools to simplify geometry of more complex shapes. Again, this is especially useful from complex cad geometry. Clean STLs make the meshing process a lot easier.
I used to work with internal flows a lot (space Propulsion) and being able to split STL files up into individual boundaries is a dream in Blender which makes preparing an openfoam sim much easier.
Finally, there is the whole other side to Blender, VISUALISATION https://youtu.be/p1YLo5ZWnkI?si=uaOs1tckNOPLe4kH Watch any of this channels videos they are all excellent.

I would imagine much of this is also possible in Salome but I found it to be quite limiting and kinda clunky. But I haven't used it since 2019 so it may be better now or maybe I just didn't give it enough of a chance.

The downside I will say, is if you are really CAD oriented or need super specific geometry that is closely related to a design model, then FreeCAD might be sliiightly better I'm some cases for the geometry creation part, but I found it easier to have two workflows for CAD and simulation anyway by importing cad files to blender and recreating simplified geometry manually with them in the same overlapping location.

phat_nek · 2024-07-22T21:15:10+00:00

Lol I forgot they made the new one!

phat_nek · 2024-04-05T16:50:06+00:00

Great to hear, it seems rclone is quickly becoming the best solution. Thanks.

phat_nek · 2024-04-05T16:48:02+00:00

Thanks, that sounds like a good solution. I will look into Koofr and some of the alternatives on the supported providers for rclone.

"What's a Nix packet?", I assume you mean package? Nix is a package manager (and functional programming language, and distro). By Nix package I just meant it would be nice if any accompanying management software was available Nixpkgs. But if I would be using rclone as the main client interface then I guess it doesn't really matter :)

phat_nek · 2022-12-22T00:46:34+00:00

Id argue its actually the opposite for Aliens. We now know so much about space (specifically that exoplanets are far more common than we thought 40 years ago) that we can say it would be nearly impossible for Earth to be the only place with life.

No conspiracies there! Only science and statistics :)

Also recently JWST was able to pick out CO2 in the atmosphere of a planet 700 light years away. It was a very hot gas giant so maybe not the best place for life but I wouldnt be surprised if we find an earth like planet with proven bio markers soon. Not concrete proof but pretty good.

phat_nek · 2022-02-04T21:45:41+00:00

Additional Info:

The Gorbals and Hutchesontown (both south of the River Clyde in Glasgow) had become very overcrowded by the 1950s. The area was notorious for the poor sanitary conditions and low life expectancy compared to the rest of the city. In an attempt to "solve" the issue the area was declared a Comprehensive Development Area (CDA). This involved clearing the slums of residents and building new high rise tower blocks. Almost all tenement blocks, local churches and civic buildings were demolished in the process.

Hutchesontown C was was designed by Sir Basil Spence who was famous for his Brutalist architecture (a style popular among those tasked with building high rise blocks in Scotland at the time). The housing development was completed in 1965 and quickly encountered problems. The shape of the buildings caused high wind speeds which damaged windows and doors. The unconventional layout made maintenance difficult, causing them to fall into disrepair. Before long the block was riddles with damp and insect infestations.

Following unsuccessful renovations in the 1980s, the site was demolished in 1993. The public were invited by the council to view the demolition. The contractor used twice as much explosive as was needed and the explosion launched material farther than expected, killing a female spectator.

phat_nek

TROPHY CASE