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Trouble Understanding Morfac

RN
Russell Nasrallah, modified 1 Year ago.

Trouble Understanding Morfac

Capillary Posts: 10 Join Date: 5/8/18 Recent Posts

Hello XBeach Community, 
I've been working with the model for approximately a year at this point and in that time have just come to accept the Morfac keyword as a mystery. I've read all I can on the forums and tried to take a look at the manual, but what the morphological acceleration factor is actually doing, and how to employ it with prudence, still elude me. I have left it at a value of 10 for all my runs since I started, as I saw posts claiming that going higher than this could be problematic. 
Can anyone help me understand how this value affects my runs?
I am currently running a Sandy Simulation for the Outer Banks of North Carolina, USA. My simulation lasts 5 days, with the peak of the storm falling in the middle of my run. I am using a Jonswap table spectrum to drive waves. I read on another forum post that:
 "Recalculating the boundary conditions more often than 5-20 minutes hydrodynamic time (so "input time"/"morfac") is generally a bad idea as it will slow the simulation and (more importantly) will not provide statistically significant time series of waves."
I've attached my params, jonswap and water level files below, in case anyone has any additional questions. 

Thanks for the help. 

P.S. If there are any additional comments or suggestions not related to the morfac question above, feel free to message me!

RN
Russell Nasrallah, modified 1 Year ago.

RE: Trouble Understanding Morfac

Capillary Posts: 10 Join Date: 5/8/18 Recent Posts

I did some additional reading in the manual and found this which clarified my question a bit:
"If you now specify a morfac of 6, the model just runs for 10 (hydrodynamic) minutes each hour, during which the bottom changes per step are multiplied by a factor 6. This of course saves a factor of 6 in computation time."

NJ
nicky jassen, modified 10 Months ago.

RE: Trouble Understanding Morfac

Capillary Posts: 7 Join Date: 9/16/19 Recent Posts
Keywords: morphodynamic modelling; MORFAC; Delft3D; long term coastal ... MORFAC approach enables numerical simulations of coastal morphological