CMS-Wave Model Parameters

CMS-Wave Model Control window Version 13.2.12.

Parameters

CMS Wave plane mode

Full plane

In this mode, CMS-Wave performs two half-plane runs in the same grid. The first run is in the half-plane with the principle wave direction toward the shore. The second run is in the seaward half-plane as opposed to the first run. Upon the completion of the second run, two half-plane results are combined to one full-plane solution (Lin et al. 2012). Because the run time for the full-plane is approximately twice of the regular half-plane, users shall consider the full-plane mode only if the full-plane features like wave generation and propagation in a bay or around an island.

Source terms

CMS-Wave is a phase-averaged model for propagation of directional irre-gular waves over complicated bathymetry and nearshore where wave re-fraction, diffraction, reflection, shoaling, and breaking simultaneously act at inlets. Wave diffraction terms are included in the governing equations following the method of Mase et al. (2005). Four different depth-limiting wave breaking formulas can be selected as options including the interaction with a current. The wave-current interaction is calculated based on the dispersion relationship including wave blocking by an opposing current (Larson and Kraus 2002). Wave generation and whitecapping dissipation are based on the parameterization source term and calibration using field data (Lin and Lin 2004a and b, 2006a). Bottom friction loss is estimated from the classical drag law formula (Collins 1972).

Bottom friction

Bottom friction could be assigned as constant or by a dataset inside SMS. To see more details, see the Bottom and wall friction of the CMS Flow. Usually, the same roughness method used on CMS Wave is used on the CMS Flow parameters bottom friction. For a detail explanation of how Bottom Friction variable is used on the CMS Wave model, see Bottom Friction

Matrix Solver

https://cirpwiki.info/wiki/CMSFlow_Matrix_Solver

Boundary control

Water level and wind information are optional source as specified under Wave Source in addition to the spectral input data.

Source

Spectral information

https://cirpwiki.info/wiki/CMS-Wave_Input_Spectra

Interpolation

• Inverse distance weighting

The inverse-distance interpolation also referred to as Shepard interpola-tion is given by (Shepard 1968)

$\phi ({\overrightarrow {x}})=\sum _{i=1}^{N}w_{i}\phi _{i}$

(17-1)

where the interpolation weights are given by

$w_{i}={\frac {d_{i}^{-\rho _{s}}}{\sum _{j}d_{j}^{-\rho _{s}}}}$

(17-2)

where

$\rho _{s}$ = real and positive power parameter [-]

d = distance between the known points ${\overrightarrow {x_{i}}}$ and the unknown interpolation points ${\overrightarrow {x}}$ equal to the Euclidean norm $d=||{\overrightarrow {x}}-{\overrightarrow {x}}_{i}||$ .

In this interpolation, the weight of each point decreases with distance from the interpolated point. One advantage of the inverse-distance interpolation is the interpolation weights are independent of the interpolation function, and therefore only need to be calculated once and can be saved for computational efficiency.[1]

Computational spectral grid

Spectral waves or wave parameters can be generated for the wave grid forcing, or wind direction and speeds can provide the necessary information for wind- wave generation. Full (directional) spectra can be imported into the SMS for the CMS-Wave, as well as simplified wave parameters (angle, wave height, and period, etc).

Case data

Wind direction angle conversion

• Cartesian
• Meteorologic
• Oceanographic
• Shore normal

Options

Date format

To setup the model parameters for CMS-Wave:

1. Go to CMS-Wave, Model Control, Options and turn on Allow wetting and drying and Bed friction

2. Users can also specify constant or varied forward and backward reflection coefficients in Settings,

To read more about CMS Wave defintions, see CMS Wave Model Control Definitions

CMS-Wave Model Control File formats

The CMS-Wave Options File (*.std) can have one of 3 input formats. Click one of the options below for the format description.

1. No cards - order of values on one line is very important.	(Used with SMS 11.1 and previous)
2. Card-based - [value] [!card name]	(Used with SMS 11.2 to 13.1)
3. Card-based - [card name] [value(s)]	(Used with SMS 13.2 and after)

Back to CMS-Wave File Formats