FLOOD - How can I change the viscosity water property using MOHID Land to model a Dam break?

Hello Jader,

At the moment, its not possible to change the properties of the default fluid which is only water by default for the various capabilities of OpenFlows FLOOD such as overland flow, flooding analysis etc. The current numerical engine of MOHID Land is not configured to be used for fluids other than water. We had a similar discussion on this forum a while ago. See the link below for reference on the forum post;

Forum Post - OpenFlows Flood

Hope this helps.

Hi Jader, indeed, as my colleague just said, the equations in MOHID are valid only for water viscosity. For instance, Mannings equations (particularly Manning's n empirical coefficient) are not valid for other fluids with viscosity different from water. Of course from a modelling perspective, you can change the Manning's n coefficient to modify the flow velocities so that you can try to "imitate" the effect that a different viscosity would have on surface flow - but this seems scientifically incorrect, and highly uncertain in terms of the validity and quality of model results.   

Thanks a lot Yashodhan Joshi.

Hi Rodrigo,

I was studying the Saint-Venant equation, and it assumes zero viscosity.

The friction term uses the Manning coefficient, but there is no viscosity in it.

Then, it would be a possible source of error between model results and experimental measurements.

Thanks a lot Rodrigo.