Changes between Version 10 and Version 11 of doc/tec/bugs


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Timestamp:
Jun 13, 2016 2:43:28 PM (9 years ago)
Author:
suehring
Comment:

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  • doc/tec/bugs

    v10 v11  
    1212'''Remarks with respect to usage of psolver = 'multigrid_noopt'''' \\
    1313
    14 In case of very complex topography, including narrow street canyons or complex shapes resolved by only a few grid points, the use of psolver = 'multigrid_noopt' in combination with masking_method = .F. can lead to a blow up of wind velocity. So far, this never happened if masking_method = .T. or psolver = 'multigrid' (where topography is always masked).
     14In case of very complex topography, including narrow street canyons or complex shapes resolved by only a few grid points, the use of [../../app/inipar#psolver psolver] = 'multigrid_noopt' in combination with [../../app/inipar#masking_method masking_method] = .F. can lead to a blow up of wind velocity. So far, this never happened if masking_method = .T. or [../../app/inipar#psolver psolver] = 'multigrid' (where topography is always masked).
    1515A possible workaround to prevent such velocity blow-up is to preprocess the topography by filling holes and removing complex shapes on the small scale before running the LES. (This approach should have no significant effect on the flow field, as in LES the flow in such regions is poorly resolved and do not yield to reliable physical information.)
    1616The reason for this velocity blow-up is unclear so far.