2 posts in this topic

Hello to All,

I have a question regarding the inline steering option that allows the coupling of CMS Flow and CMS Wave in order to simulate the effects that waves may have on currents and vice versa. My question arises after running multiple simulations in which we are not seeing any effects in current magnitude from any given simulated wave spectra for multiple wave events over a given time series. We are trying to replicate a given time series of currents, water level, and wave events from an in-situ ADCP that is within the model domain, aka our calibration point. I have included a plot of the results illustrating my problem which shows the simulated wave height and current magnitude (metric units) at our calibration point which is in 7 meters of water and located approximately mid domain about 380 meters offshore post-43740-0-05948000-1394203136_thumb.p. With a given wave event reaching a peak height of 2+ meters we see little change in current magnitude during the event where as at the in situ gage we see a significant increase in velocity. Now I realize this is a depth averaged model and I compared it to the depth averaged result from our ADCP to keep things on the same page.

However the truly confusing part is that in the nearshore zone (less than 200 meters offshore) we see a significant increase in current magnitudes during a wave event similar to what you would expect in reality post-43740-0-46898200-1394204427_thumb.p (red is the nearshore observation point, wave height and Magnitude). So it appaears that we have a spatial problem relative to our calibration point. I have tried expanding the grid further offshore by several hundred meters on a constant 20x20 meter grid with no change in results.

At this point I am stumped after adjusting the various coefficients available within SMS. I attached a screen shot of the last values used in the Flow Parameters section in case anybody has any suggestionspost-43740-0-40485600-1394204569_thumb.p. I have tried adjusting the variables from 0 to 1 with multiple steps in between with marginal changes in results.

We are currently running SMS 11.1.11 64bit and I would be greatful if anybody has any suggestions or ideas as to what I might be doing wrong in order to see an increase in current magnitude at the calibration point. Thank you in advance for your time.

Cheers,

Joe

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It is hard to be sure what is going on without looking at the model setup, solution, and data, but from what you describe it seems like the simulated waves are not breaking early enough to generate currents at your (deeper) calibration station. Unfortunately, CMS-Wave does not give the user the option to calibrate the wave breaking and default parameters are used. However, given the 2-m wave height and 7-m water depth, I wouldn't expect much wave breaking. It could be that the current you are observing is actually generated in shallower water but is not being captured by the model. You can try increasing the cross-shore resolution to see if that improves the results.

Edited by Alex Sanchez

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