CMS-Flow Wind Forcing
Wind Curve
Temporally varying, spatially constant winds are input in CMS in the Wind Section of the CMS-Flow Model Control Window. To add wind forcing to a current CMS-Flow project click on CMS-Flow | Model Control and then on the Wind/Wave tab. Activate wind forcing by clicking on the Include Wind check box. Winds may be imported using an *.m2w file or by specifying a curve for wind speed and direction. To specify a curve for each click on the respective box which says Curve undefined which will open the XY Series Editor. The time series may be manually entered, copied or imported from an *.xys file in the XY Series Editor.
Spatially Variable Wind and Atmospheric Pressure
CMS-Flow V4.0 and higher have the option to use spatially variable wind and atmospheric pressure forcing. Currently, this feature is specified in the advanced card section using the cards listed in the table below.
CMS-Flow cards related to wind
| Card | Arguments | Type |
|---|---|---|
| WIND_OUT_TIMES_LIST | Id number of output times list | integer |
| WIND_DRAG_COEFFICIENT | kappa in Hsu (1988) (default 0.4) | real |
| WIND_INPUT_CURVE | Name of model parameter file followed wind curve path | character |
| ANEMOMETER_HEIGHT | Height of wind speeds | meter |
| OCEANWEATHER_WIND_FILE | Name of Oceanweather, Inc. wind file (*.win) | character |
| OCEANWEATHER_PRES_FILE | Name of Oceanweather, Inc. pressure file (*.pre) | character |
| OCEANWEATHER_XY_FILE | Name of Oceanweather, Inc. coordinate file (*.xy) | character |
| WIND_PRESSURE_FLEET_FILE | Name of fleet wind and pressure file | character |
| WIND_PRESSURE_GRID_PARAM | Nwlat,Nwlon,wLatMax,wLonMin,wLatInc,wLonInc | integer and real |
| WIND_PRESSURE_TIME_INCREMENT | wTimeInc | real |
- Notes:
- 1. Interpolation File: When using spatially variable winds CMS V4.0 will output a file named Intpcoef_wndfl.bin. This file contains the coefficients used to interpolate the winds and atmospheric pressure to the CMS-Flow grid. If the same flow and wind grids are run, the model will automatically detect the interpolation file and read in the coefficients instead of calculating them. If the either grid is changed in size, the model will automatically detect this and recalculate the coefficients. However, if the grids are changed but stay the same size, the model will not be able to detect that they have changed. Therefore, whenever any changes are made to the flow or wind grids, it is best to delete the interpolation file.