Hello, I’m wondering, in a pure 2D model (for example a dam break simulation) is significant to set up the eddy viscosity mixing coefficient? I know that the default value (using the Full momentum equation) is blank (equal to 0), and so is not the “eddy viscosity model” taken into account? If this is an important value to set up, why the default is blank?
For a dam break, I wouldn’t worry about it. The default is set to zero and the model ignores it. There is discussion about it in the manual and a range of values, but most people just ignore it when they use HEC-RAS.
In general you should always calibrate and validate your model and this could be a knob to turn to help calibrate.