y

Internal Wave Generation Boundary

(x max , ymax)

Wave

Direction

Porous Structure

Damping Regions

( xorigin , yorigin)

x

Figure 6.

Definition sketch for computational grid

predominant wave direction.

wavelength away from the boundaries to minimize the effect of

diffraction into the damping layers.

interest (*T*min) in the shallowest part of the domain (*h*min). This typically

corresponds to having at least eight grid points per wavelength in the

shallow regions and 20 to 30 points per wavelength at the peak wave

period (*T*p) in the deep regions (*h*max).

length of interest (*h*max ≤ *L*(*T*min)*/*2)*. *In regions with relatively deep water

along the offshore boundary, an artificial maximum depth can be

imposed in the numerical model to ensure that the shortest waves of

interest are resolved. For example, if we are interested in modeling a sea

state with *T*p =10 *s *and *T*min = 6 *s *over an area where the water depth

ranges from 5 m to 100 m, a maximum depth of 28 m can be imposed

corresponding to *L*(*T*min)/2.

The maximum size of the computational area should be based on the

amount of available computational resources. For typical PC's or work-

stations with 100 to 200 MB of virtual memory, the grid size should not

exceed 500 x 500 grid points. Larger grids can be used at the cost of

much longer computational times.

29

Chapter 4 Setting Up and Running BOUSS-2D

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