Prescribing equilibrium concentration at a single open boundaryPrescribing equilibrium concentration at a single open boundaryhttps://oss.deltares.nl/c/message_boards/find_thread?p_l_id=1806765&threadId=861692021-02-27T18:17:59Z2021-02-27T18:17:59ZRE: Prescribing equilibrium concentration at a single open boundaryAlberto Canestrellihttps://oss.deltares.nl/c/message_boards/find_message?p_l_id=1806765&messageId=878802011-10-26T00:36:59Z2011-10-26T00:36:59ZMmm I noticed that if you prescribe the thatcher lag time =-1 also the salinity has the "equilibrium concentration" in the sense that a newmann condition dc/dx is applied to the boundary (i.e. for inflow the value inside the domain is copied on the boundary). That it is clearly not a good thing because it means that no salinity is entering the domain at any time, and if you start with some salinity inside the domain it fast exits the domain and it never comes back. It looks like its impossible to prescribe salinity and equilibrium sediment concentrations together at a single boundary. anybody confirming this?<br />Thanks<br />AlbertoAlberto Canestrelli2011-10-26T00:36:59ZRE: Prescribing equilibrium concentration at a single open boundaryAlberto Canestrellihttps://oss.deltares.nl/c/message_boards/find_message?p_l_id=1806765&messageId=878462011-10-25T20:16:34Z2011-10-25T20:16:05ZOk I have found the way to do it, you have just to prescribe a Thatcher-Harlemann time lag equal to -1. I did not see that possiblility at first. <br />Cheers<br />AlbertoAlberto Canestrelli2011-10-25T20:16:05ZPrescribing equilibrium concentration at a single open boundaryAlberto Canestrellihttps://oss.deltares.nl/c/message_boards/find_message?p_l_id=1806765&messageId=861682011-10-14T15:17:06Z2011-10-14T15:17:06ZDear all,<br />I noticed that in Delft3D there is only the option to prescribe an equilibrium concentration (Neumann condition, NeuBcSand=true for sand and NeuBcMud=true for mud) at ALL the open inflow boundary, but it is not possible to prescribe it only at a particular boundary. I am trying to simulate the long term evolution of a river debouching in a tidal basin. I am prescribing a (non-equilibrium) entering concentration in the upstream boundary of the river, while I would like to have a Neumann condition at the downstream boundary, where I prescribe the tide. It looks like this is not possible, because if I have sand and I add NeuBcSand=true the Neumann condition applies to ALL the boundary and overwrite my upstream condition. or am I missing something?<br />thanks<br />cheers<br />AlbertoAlberto Canestrelli2011-10-14T15:17:06Z