CMS-Flow:Explicit

In the explicit flow solver, the water level is clamped. For cases in which the ocean domain is relatively large and spatially variable water levels or velocities occur, water level and velocity (flux) BCs are available. The spatially variable water levels and velocities may be extracted from a larger regional models such as ADCIRC (Luettich et al. 1992) or CMS simulation or from a tidal constituent database. When applying a Water Level BC to the nearshore, the wave-induced setup is not included and can lead to local flow reversals and boundary problems. In the explicit flow solver, this problem is avoided by implementing a Wave-adjusted Water Level BC (Reed and Militello 2005). In the implicit flow solver a similar wave-adjusted BC is applied by solving the 1-D cross-shore momentum equation including wave and wind forcing (Wu et al. 2011a, 2011b).

The hydrodynamics is coupled to sediment transport (also in CMS-Flow) and the wave model, CMS-Wave. Some important features and processes included are: wetting and drying, wave and surface roller stresses, wave mass fluxes, wave-enhanced bottom friction, turbulent diffusion, wall friction, Coriolis force, spatially variable wind and atmospheric pressure, and vegetation flow drag. Both explicit and implicit time marching schemes are available. The explicit scheme is designed for highly transient flow and extreme wetting and drying problems which require small time steps. The implicit scheme is designed for tidal flow and long-term simulations where large time steps can be used on the order of 10 min. CMS versions 4.0 and higher have both CMS-Wave and CMS-Flow in a single executable (code) for faster and more efficient model coupling. The CMS is parallelized using OpenMP. Additional information about CMS-Flow is available from the CIRP website: http://cirp.usace.army.mil/wiki/CMS-Flow.

Reference: CMS Flow Technical Report 3 More information and validation: https://cirpwiki.info/wiki/Transcritical_Bump