I developed a 2D model using HEC-RAS 5.0.0 Beta (August 2015) that included a road/culvert crossing inside the 2D mesh that was added using the SA/2D Area Connection tool, and the model was working properly with the Beta software version.
When the official release of HEC-RAS 5.0.0 (February 2016) became available, I downloaded the new version and ran the model with the updated software version. For some reason the culverts are no longer conveying flow to the downstream cells. The model runs without any errors or warnings, but the upstream flow accumulates in the channel until it overtops the roadway.
I have checked and rebuilt the structure multiple times and reviewed the 2D User’s Manual, but I cannot find anything with the model that would be causing this issue. The upstream and downstream cells are connected and the culvert elevations are slightly above the minimum cell elevations. I realize there can be some instabilities under low flow conditions, but the model is developing over 5 ft. of headwater without conveying any flow through the culvert downstream. I have also tried multiple computational intervals ranging from 0.2 seconds to 2 seconds. I’m not sure what would have changed with the latest release, but any help would be appreciated.