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  1. SomptingGuy

    Two Inventions of 1885 that changed the World

    For fans of James Burke (I include myself here), this episode of Infinite Monkey Cage is well worth a listen. https://www.youtube.com/watch?v=0ZOZA2nJLxs No scientific background. Employed by the BBC as a non-scientist to present science. Steve
  2. SomptingGuy

    Interactive simulations in the cloud

    @IRstuff I'm quite old too. My first programs were on coding sheets, mailed to the local polytechnic. Returned a week later with a syntax error. Batch computing is still dull. It's the idea of interactive simulations with a remote computer that interests me. Like playing Doom using an internet...
  3. SomptingGuy

    Interactive simulations in the cloud

    Looking for experiences here... I'm fairly familiar with the new simulation paradigm being pushed: - Set up simulations locally on low-end device - Submit to high-end (massively parallel) devices in "the cloud" - Get results back Licensing all happens in your cloud account, not on the local...
  4. SomptingGuy

    Partitioning Hard Drives

    Whatever the size of your storage, it'll always be 95% full. Like your garage. It's easier to keep small storage places sensibly clean and tidy. Steve
  5. SomptingGuy

    Dynamic torque signature

    When you say "the crankshaft is infinitely long", did you mean the connecting rod? Otherwise, nobody has mentioned the effects of basic engine balancing. For an I4 engine, the level of the 2E out-of-balance is strongly affected by the bore/stroke ratio. And for most automotive I4 engines...
  6. SomptingGuy

    Are you using an old version?

    Thanks Greg, I got a similar reply from one of our internal users here (different team, different Matlab use). They are still stuck at 32-bit 2010. Steve
  7. SomptingGuy

    Simulink versions

    If you are using an old version of Simulink, why? I'm wondering what constraints exist in the engineering workplace that might cause users to want to stick with older versions. For example: "My tool-chain has elements that require nothing newer than R2015b", or "My HiL tool needs exactly 32-bit...
  8. SomptingGuy

    Are you using an old version?

    If you are using an old version of Matlab, why? I'm wondering what constraints exist in the engineering workplace that might cause users to want to stick with older versions. For example: "My tool-chain has elements that require nothing newer than R2015b", or "My HiL tool needs exactly 32-bit...
  9. SomptingGuy

    Tuned intake length

    The good books for this stuff are those by Winterbone & Pearson: "Theory of Engine Manifold Design: Wave Action Methods for IC Engines" "Design Techniques for Engine Manifolds: Wave Action Methods for IC Engines" Worthy additions to any automotive engineering library. Steve
  10. SomptingGuy

    Autopower Crosspower nomnclature

    More... I see some online resources stating that H1(f)=Gxy(f)/Gxx(f) and others that H1(f)=Gyx(f)/Gxx(f). The former being more common. The latter (IMO) giving the phase relationship I'd expect (y, a pure delayed version of x causes a decreasing phase ramp in H1). Steve
  11. SomptingGuy

    Autopower Crosspower nomnclature

    Yes hacksaw. All of what you say is true and completely familiar (apart from the bit about the HP doc only dealing with single inputs, which is not true). I only asked if anyone knew why G was the letter universally used in the notation. I wondered if there was a mathematician being honoured or...
  12. SomptingGuy

    Autopower Crosspower nomnclature

    I've nearly given up looking. Even some of my favourite references just introduce Gxy as a function. I thought Appenix A in HP Application note 243, The Fundamentals of Signal Analysis might give some background as it's such a good general read. Steve
  13. SomptingGuy

    Autopower Crosspower nomnclature

    So we are all happy with the terms Gxx, Gyy, Gxy in our signal processing world. But does anyone know where the letter G came from? I was trying to explain these things to a colleague today, but all I could point to were definitions of Gxx,Gxy,Gyy. Not why we use the letter G Steve
  14. SomptingGuy

    Generating a Power Spectral Density with Un-Even Spacing

    If you only want values at specific values, why not just do it long-hand for the frequencies that interest you? No need to do a full transform. Steve
  15. SomptingGuy

    Co-Simulation Issue

    All else being the same, check units and sign conventions. Plot the error signal if you can access it. Will be simple inside Simulink, hopefully not too difficult in ADAMS. Steve
  16. SomptingGuy

    There are apparently TWO standard foot measurements...

    Now if that golf tournament were in honour of famous grocers, we'd have a real apostrophe war on our hands. [2thumbsup] Steve
  17. SomptingGuy

    Freakin' Patent Office

    In my experience, patent lawyers argue with other patent lawyers about things they don't understand, using word association as their main device. Steve
  18. SomptingGuy

    Sound pressure levels to Third Octave bands

    If your CFD simulation is giving you dB values, you'll need to convert them back to pressures and calculate the RMS. People often get confused about this, trying to remember a magic formula and mixing up 10s and 20s in the calculation. Just work from first principles and realise that you are...
  19. SomptingGuy

    Diesels: volumetric efficiency versus boost

    That's an interesting metric to want to measure. (The standard definition of) VE is normally the holy grail for N/A engines, kinda irrelevant when you're pumping the intake up to whatever pressure you want. You could easily compute your metric from any of the 1D engine simulations out there. It...
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