SSW BBL

class="title">SSW bottom boundary layer formulation

Wave-orbital calculations

<wikitex>Near-bed wave-orbital characteristics, including representative orbital velocity $u_{br}$, representative period $T_r$, and average direction of wave propagation $\theta_w$ (degrees, nautical convention, which is positive clockwise from north) are defined according to Madsen (1994). When SWAN results are used, these correspond to UBOT, PWAVE, and DWAVE. If surface-wave statistics (e.g., $H_s$, $T_d$, and $\theta_w$) are provided, they can be converted to bottom orbital velocity externally (using, for example, the routines suggested in Wiberg and Sherwood (2008) and provided as UBOT in a SWAN input file. Alternatively, if SSW_CALC_UB is defined, orbital velocity $u_{br}$ is calculated according to linear wave theory as follows: $$ u_{br} = \frac{H_s}{2\sinh (kh)} $$ where $kh$ is wavenumber x depth, and $k$ can be approximated using one of the methods described here.</wikitex>

Ripple Geometry

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Bottom Roughness

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Wave-current combined stress and roughness

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Skin friction - form drag partitioning

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Maximum shear stress

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