{"action":"created","issue":{"url":"https://api.github.com/repos/noSoulApophis/incremental-fluids-java/issues/2","repository_url":"https://api.github.com/repos/noSoulApophis/incremental-fluids-java","labels_url":"https://api.github.com/repos/noSoulApophis/incremental-fluids-java/issues/2/labels{/name}","comments_url":"https://api.github.com/repos/noSoulApophis/incremental-fluids-java/issues/2/comments","events_url":"https://api.github.com/repos/noSoulApophis/incremental-fluids-java/issues/2/events","html_url":"https://github.com/noSoulApophis/incremental-fluids-java/issues/2","id":176222603,"number":2,"title":"On TunaBrains code, i just noticed,  rotating and or translating the paddle in the test does not move the Body, and then the solver fails...","user":{"login":"damian-666","id":16763801,"avatar_url":"https://avatars.githubusercontent.com/u/16763801?v=3","gravatar_id":"","url":"https://api.github.com/users/damian-666","html_url":"https://github.com/damian-666","followers_url":"https://api.github.com/users/damian-666/followers","following_url":"https://api.github.com/users/damian-666/following{/other_user}","gists_url":"https://api.github.com/users/damian-666/gists{/gist_id}","starred_url":"https://api.github.com/users/damian-666/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/damian-666/subscriptions","organizations_url":"https://api.github.com/users/damian-666/orgs","repos_url":"https://api.github.com/users/damian-666/repos","events_url":"https://api.github.com/users/damian-666/events{/privacy}","received_events_url":"https://api.github.com/users/damian-666/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":32,"created_at":"2016-09-11T05:40:29Z","updated_at":"2016-09-19T21:46:46Z","closed_at":null,"body":"Just wondering if you implemented it and if it is stable enough to use...\r\n\r\n\r\n I was thinking to apply drag, from thw wikipedia drag equation , then push the fluid away from the normals of the immersed thing.   but i'd rather do it that way CBatty did.. i have some of that some...  i can put the link.. its on a big page on Variational methods.. it gives away 2d code for gas ( with 3 circles... i could move those.. and it pushes away the liquid.. with a one frame delay, it seems.. but the shape is nice, and it does not miss any of the fluid...    I see code that mentions forward Eulear.. so i was hoping you know something about it.. .. I will report to Tunabrain as well...I think the temperature gradients  is the focus of this code....."},"comment":{"url":"https://api.github.com/repos/noSoulApophis/incremental-fluids-java/issues/comments/248137338","html_url":"https://github.com/noSoulApophis/incremental-fluids-java/issues/2#issuecomment-248137338","issue_url":"https://api.github.com/repos/noSoulApophis/incremental-fluids-java/issues/2","id":248137338,"user":{"login":"damian-666","id":16763801,"avatar_url":"https://avatars.githubusercontent.com/u/16763801?v=3","gravatar_id":"","url":"https://api.github.com/users/damian-666","html_url":"https://github.com/damian-666","followers_url":"https://api.github.com/users/damian-666/followers","following_url":"https://api.github.com/users/damian-666/following{/other_user}","gists_url":"https://api.github.com/users/damian-666/gists{/gist_id}","starred_url":"https://api.github.com/users/damian-666/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/damian-666/subscriptions","organizations_url":"https://api.github.com/users/damian-666/orgs","repos_url":"https://api.github.com/users/damian-666/repos","events_url":"https://api.github.com/users/damian-666/events{/privacy}","received_events_url":"https://api.github.com/users/damian-666/received_events","type":"User","site_admin":false},"created_at":"2016-09-19T21:46:46Z","updated_at":"2016-09-19T21:46:46Z","body":"Hello again.   I have  compared your code and yes it appears there is is\nbasically a straight port from tunabrain.\n\nthanks for porting it .. i think i might giveit a port to c# unless you\nknow a better way to do multiple density gas  with immersed boundary.  I\nhave tried stuff and play to try more with this code and solver.   So just\nletting you know my plan and about a few more things i read about that\nmight interest you.\n\nI have found some but the license is GPL...  i dont think a port to c# will\nclear me.  I dont want to show my creature code just because they swim in\nsomeone elses fluids..\n\nI think i am going to try it.. i like what i see so far.   I do wan air\nover water eventually.. and definitely Adaptive grids..\n\n but  the results for multiple density are good..  when the object is hot.\n\nI dont get convergence on the second pass and so I tried to set the\nvelocity only after the entire solve   This is a very weak coupling.  Then\nas you suggested , i move  the fluid around the object using a direct\nsetting of the fluid velocity  ( will need to be careful of the maximum\nchange or flux allowed) .\nand apply panel drag to my IB based on the density near the panel.\n\nbecause my immersed object is small compared to the gas, ( in air) and\nspeed is far more important than accuracy, I tried this with fair results.\n  the gass seems pushed out of the way if the box is thick enough.\n\nIt seems, why should the solver need to know the velocity of the IB if it\nwill simply be one frame late?  by then it will be reflected in the fluid\nusing a direct forcing as the initial conditions.\n\n\n*-solve pressure.  ( without the velociy of IB  objects) *\n\n*-draw*\n\n*-apply drag.*\n\n*-apply direct forcing .*\n*repeat *\n\n\n\n   I dont know exactly why it didnt converge, i think that the velocity\nneeded to be multipled by DT in some places.  However, it still didnt solve.\n\nI find good enough results\nusing the panel method, adding a drag =   1/ vel * vel   x panel length\n normal to the relative  flow , at two points on each panel that is a loose\nbody.   skipping all small panels.\n\n\n  Ghost matter might be needed to \"thicken\" panels, or use collision\ndetection for each particle.. if i use shaders to manage the particles and\ndetect collisions using   graphics AND code\n\nI dont feel i was to use vorton methods are there are tons..\n\n   So, the solver there seems good enough if the grid is less that 256 x256\n  I will look for a shader version.   Or i will try to Cudaify it...\n\n\nBut herer is another IB method  i havent explored...\n\nhttps://github.com/barbagroup/petrbf\n\n\n\nI have FLIP code from Martin Quay that uses a graphics Guassian Splat to\ndetermine the density graphically.   For 2d there are many tricky and\n\"visual\" ways to solve for pressure, and  some are begging for an all\nshader solution.  for the collision, for the density , the retendering, and\nthe fluid dynamics.\nI get about 200,000 particles... but its too slow... no temperature.. no\nlevel sets...not adaptive grid...\n\nBut i am still wondering about using a 1024x1024 grid  for the entire\natmosphere..\n\n\na google for Spectral methods on incompressible fluids shows many ways.\n\nperiodic meaning inflow on one end, equal outflow of mass on the other (\nand hidden stuff in the margins)\n\n\nFor a two phase free boundary i am not sure.   Perhaps  two solvers\nentirely: one for air, using the water surface as an IB..  and taking its\nvelocity in the normal direction at as affecting the fluid velocity near\nthe interface, and vice versa to a different extent based on the mass ratio.\n\n  I do see FFT  on GPU solutions.\nhttps://slashdot.org/story/06/05/29/1424213/high-performance-fft-on-gpus\n\n\nin python there are many ways to do IB.     but i hate python.. i could use\nIronpython since it compiles... or .net..\n\n\nand i find  many papers on using th e FFT for a pressure solve.\n\n\n48x    thats what i like.   i even see 1000x  when using Jacobi free Krylov\nmethods..\n\nhttp://www.nvidia.com/content/new_cudawmfg/cudabrowser/\nassets/data/applications.xml\n\nits really easy to just read and read and read...\n\njust sharing some stuff.\n\n\n\n\n\nOn Mon, Sep 12, 2016 at 9:27 AM, Damian Hallbauer <\ndamian.hallbauer@gmail.com> wrote:\n\n> 20x faster?     or 4x...  i read for the fast FFT it doesnt matter..\n> better do it on the CPU. or where ever the data is ...   visual studio\n> update has some texture compression stuff .. and i read if its 64k i\n> think.. its fits in one warp.... i might try Cudaify.. .. i was doing\n> almost realtime mandelbrot at full resolution...with an opencl demo..  so\n> im planning ot use some 1 bit.. 2 bit ..\n> paletted bitmaps..if i have to pass them around.\n>\n>\n> i would love if openCL finds the processor in skylake, and if the is an\n> AMD or nvidia ,,the we could use them both on newer machines..     skylake\n> GPU on the chip is almost good enough,, not quite ...  so alot of systems\n> will have two powerful\n> gpus.    i cant seem to query my intel one..but i think its too old..\n>\n> im still thinkingo of the FFT solv.. there are alot of tricks..  here are\n> a few more papers..  if its just for pressure solv in air...the presence of\n> one  small 2d character, would not ruin it..just not be perfectly accurate?\n>   the FFT region might just be the sky ... then using some other grids in\n> chimera style....\n>\n> i guess its pretty easy to try them... for a side scoller game.. the\n> boundaries are often good enough..\n>\n> http://ms.mcmaster.ca/~bprotas/MATH745c/spectr_01.pdf\n>\n> http://ufrmeca.univ-lyon1.fr/~buffat/FDMIF/articleIBM.pdf\n>\n>\n> .https://people.eecs.berkeley.edu/~demmel/cs267_Spr05/Lectur\n> es/Lecture26/Lecture_26_AMR_part2_PhilColella_05.pdf\n>\n> On Mon, Sep 12, 2016 at 5:06 AM, Gonçalo Amador <notifications@github.com>\n> wrote:\n>\n>> Used GPU before with CUDA and OpenCL the times in the thesis actually can\n>> be way faster.\n>>\n>> —\n>> You are receiving this because you authored the thread.\n>> Reply to this email directly, view it on GitHub\n>> <https://github.com/noSoulApophis/incremental-fluids-java/issues/2#issuecomment-246204629>,\n>> or mute the thread\n>> <https://github.com/notifications/unsubscribe-auth/AP_LmaSlxuQrAmU6MHvW0vp0Sgat3H8Fks5qpG1RgaJpZM4J56kt>\n>> .\n>>\n>\n>\n"}}
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