CMS-Flow:Boundary Conditions: Difference between revisions

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== Tidal Constituent==
== Tidal Constituent==
The CMS follows the National Oceanographic and Atmospheric Administration (NOAA) National Ocean Service (NOS) convention for astronomical water level predictions. The water level predictions are based on a harmonic equation with several arguments
The water level predictions are based on a harmonic equation with several arguments


{{Equation|<math> \eta(t) =  \sum_{i=1}^N f_i A_i \cos (\omega_i t + V_{i}^0 + u_i - \kappa_i)  </math>|2=1}}
{{Equation|<math> \eta(t) =  \sum_{i=1}^N f_i A_i \cos (\omega_i t + V_{i}^0 + u_i - \kappa_i)  </math>|2=1}}


where <math>A</math> is the constituent ''mean '' amplitude, <math>f</math> is a factor that reduces the mean amplitude and varies in time, <math>V_0+u</math> are the constituents ''equilibrium '' phase and <math>\kappa</math> is the constituent phase lag or epoch.
where <math>A</math> is the constituent ''mean '' amplitude, <math>f</math> is a factor that reduces the mean amplitude and varies in time, <math>V_0+u</math> are the constituents ''equilibrium '' phase and <math>\kappa</math> is the constituent phase lag or epoch.
== Flux ==
The water flux is specified as m^3/sec per cell along the cell string. This value is multiplied by the number of cells in the cell string to obtain the total flux.
The total flux is then redistributed along the boundary according to
{{Equation|<math> q_i  = frac{Q_{b}}{ \sum_{i=1}^N h_i^{1+r} / n_i}  h_i^{1+r} / n_i </math>|2=2}}


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Revision as of 15:18, 23 June 2010

Water Level

Water Level and Current Velocity

Tidal Constituent

The water level predictions are based on a harmonic equation with several arguments

  η(t)=i=1NfiAicos(ωit+Vi0+uiκi) (1)

where A is the constituent mean amplitude, f is a factor that reduces the mean amplitude and varies in time, V0+u are the constituents equilibrium phase and κ is the constituent phase lag or epoch.

Flux

The water flux is specified as m^3/sec per cell along the cell string. This value is multiplied by the number of cells in the cell string to obtain the total flux. The total flux is then redistributed along the boundary according to


  qi=fracQbi=1Nhi1+r/nihi1+r/ni (2)

Symbol Description
t Time
A Constituent mean amplitude
f Constituent nodal factor
V0 Constituent equilibrium argument
u Constituent equilibrium argument
κ Constituent phase or epoch

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