{"action":"closed","issue":{"url":"https://api.github.com/repos/firemodels/fds-smv/issues/2409","labels_url":"https://api.github.com/repos/firemodels/fds-smv/issues/2409/labels{/name}","comments_url":"https://api.github.com/repos/firemodels/fds-smv/issues/2409/comments","events_url":"https://api.github.com/repos/firemodels/fds-smv/issues/2409/events","html_url":"https://github.com/firemodels/fds-smv/issues/2409","id":91002732,"number":2409,"title":"CONVERT_VOLUME_TO_MASS issue in FDS 6.2.0","user":{"login":"gforney","id":12403014,"avatar_url":"https://avatars.githubusercontent.com/u/12403014?v=3","gravatar_id":"","url":"https://api.github.com/users/gforney","html_url":"https://github.com/gforney","followers_url":"https://api.github.com/users/gforney/followers","following_url":"https://api.github.com/users/gforney/following{/other_user}","gists_url":"https://api.github.com/users/gforney/gists{/gist_id}","starred_url":"https://api.github.com/users/gforney/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/gforney/subscriptions","organizations_url":"https://api.github.com/users/gforney/orgs","repos_url":"https://api.github.com/users/gforney/repos","events_url":"https://api.github.com/users/gforney/events{/privacy}","received_events_url":"https://api.github.com/users/gforney/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/firemodels/fds-smv/labels/Application-FDS","name":"Application-FDS","color":"ededed"},{"url":"https://api.github.com/repos/firemodels/fds-smv/labels/OpSys-All","name":"OpSys-All","color":"ededed"},{"url":"https://api.github.com/repos/firemodels/fds-smv/labels/Priority-Medium","name":"Priority-Medium","color":"ededed"},{"url":"https://api.github.com/repos/firemodels/fds-smv/labels/Type-Defect","name":"Type-Defect","color":"ededed"}],"state":"closed","locked":false,"assignee":{"login":"drjfloyd","id":12799217,"avatar_url":"https://avatars.githubusercontent.com/u/12799217?v=3","gravatar_id":"","url":"https://api.github.com/users/drjfloyd","html_url":"https://github.com/drjfloyd","followers_url":"https://api.github.com/users/drjfloyd/followers","following_url":"https://api.github.com/users/drjfloyd/following{/other_user}","gists_url":"https://api.github.com/users/drjfloyd/gists{/gist_id}","starred_url":"https://api.github.com/users/drjfloyd/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/drjfloyd/subscriptions","organizations_url":"https://api.github.com/users/drjfloyd/orgs","repos_url":"https://api.github.com/users/drjfloyd/repos","events_url":"https://api.github.com/users/drjfloyd/events{/privacy}","received_events_url":"https://api.github.com/users/drjfloyd/received_events","type":"User","site_admin":false},"milestone":null,"comments":11,"created_at":"2015-06-25T15:53:21Z","updated_at":"2015-10-22T14:47:23Z","closed_at":"2015-10-22T14:47:23Z","body":"```\nPlease complete the following lines...\n\r\nFDS Version:6.2.0\r\nSVN Revision Number: 22420\r\nCompile Date: 05/25/2015, source code complied by user on local workstation\r\nSmokeview Version/Revision: N/A\r\nOperating System: RedHat 6\r\n\r\nDescribe details of the issue below:\n\r\nThe original intention was to use the \"CONVERT_VOLUME_TO_MASS\" flag combined with the\nvelocity boundary conditions to better conserve the mass (as described in the user\nguide) of Nitrogen gas injected from a vent that is located in the computational domain.\n\r\n\r\nI downloaded the source code (svn22420) and compiled it successfully under teh intel12\nand openmpi163 environment.\r\n\r\nThe attached input file (\"N2_injection.fds\") shows the configurations in detail. The\nvent has an area of 8cm x 8cm, from which the N2 gas is injected into a sealed domain\nat an velocity of 7.12 m/s for 10 seconds. Thus the total injected N2 gas mass is supposed\nto be 0.5468kg at the end of the discharge. In order to monitor the injected N2 mass,\ntwo approaches were adopted: (1) the \"MASS_FILE\" is set to be \"TRUE\", such that the\ntotal mass in the domain can be recorded as a function of time. By subtracting the\ninitial value of mass from the final value obtained at the end of 10s, we can get the\ninjected mass of N2 gas; (2) A device integrating the total injected N2 gas mass. \r\n\r\nThe results, however, turned out to be non-ideal. From the \"MASS_FILE\" approach, the\nN2 mass injected was -0.5kg (yes, it's negative), whilst the device integral gives\nZERO value for the injected N2 mass. These results are not reasonable at all. \r\n\r\nIn order to verify the results, I then used soly the velocity BC (VEL= -7.12 m/s) without\nthe \"CONVERT_VOLUME_TO_MASS = .TRUE.\". By doing so, I got 0.719kg of injected N2 mass\nvia the \"MASS_FILE\", and 0.8775 kg of injected N2 mass via the  device integral approach.\nNeither of these values are close to the target value of 0.5468kg. Besides, these two\nvalues (0.719kg and 0.8775kg) are not consistent with each other. I am not sure why\nthis would happen.\r\n\r\nAs a third test, I no longer use the velocity BC, but use simply the MASS_FLUX BC instead.\nIn this case, I set MASS_FLUX = 7.12 x 1.2 = 8.544 kg/m^2/s, which corresponds to a\ntotal injection of 0.5468 kg N2 mass after 10s discharge. The results are 0.5818 kg\nand 0.7146 kg from the \"MASS_FILE\" and device integral, respectively. Again, they are\nnot equal to 0.5468 kg, and they are not consistent with each other.\r\n\r\nI also did the same tests using SVN  22551, and got the same behavior.\r\n\r\nSo my questions are:\r\n(1) why the CONVERT_VOLUME_TO_MASS + vel BC seems not working at all (negative injected\nmass from \"MASS_FILE\" and ZERO value from device integral)?\r\n\r\n(2) why even the vel BC itself doesn't work, either? Specifically, why the injected\nN2 gas mass obtained from the two methods are not consistent?\r\n\r\n(3) why the MASS_FLUX BC does not conserve mass, either?\r\n\r\nI would greatly appreciate it if you could give me some hint on these issues. FYI,\nthe FDS input file used for the aforementioned tests is attached.\r\n\r\nThank you very much. \n```\n\nOriginal issue reported on code.google.com by `CharlieBrownUCI` on 2015-05-28 04:09:10\n<hr>\n * *Attachment: [N2_injection.fds](https://storage.googleapis.com/google-code-attachments/fds-smv/issue-2451/comment-0/N2_injection.fds)*"}}