You are here

Home › Forums › W2 Forum › Hydrodynamics

Wind

Mon, 06/25/2007 - 12:42pm — nick
Why does the preprocessor give warnings for wind speeds in excess of 20 m/s? Though that is a high wind speed it is certainly possible. This leads to another question regarding wind that I have. I have several models that tend to over mix during prolonged periods of high wind. Meteorological data for one of these models comes from a raft in the reservoir. In most cases I have to reduce the wind sheltering coefficient or edit the actual wind data. Has anyone else had similar experiences? Is mixing too sensitive to wind in the model? Thank you for your comments.
Forums: 
Hydrodynamics
Mon, 07/16/2007 - 11:10am — Rob

The preprocessor is designed to check all the input files. It gives warning for wind speeds above 20 m/s because wind speeds this high are less common so it serves as a check for the model user to ensure their input data is correct. If you are confident the wind speeds are this high then you can ignore the preprocessor warnings. Wind speed data varies a lot from site to site and even though some of your wind data is taken from on the reservoir itself there can be instances when the effective wind on the surface is less. For example, if you have a reservoir that changes its orientation angle over its length. In one reach of the reservoir winds may be high but when the channel orientation changes the winds are reduced or simply follow the new channel direction. You can change the WINDH variable to reduce the wind on the surface in addition to using the Wind Sheltering coefficient. If you have to edit the wind data then I would revisit the data and compare it to data from other sites in the area to identify if the wind speeds are within a reasonable range across several sites. Lastly, you can also modify the vertical eddy diffusivity coefficient to reduce mixing.