Stream function waves

The following parameters can be modified: 

Stream function wave

Angle

The angle between the direction of the waves and the north direction. For example, an angle of 90 degrees leads to the waves coming from the east direction.


  • Default value: 0
  • Unit: $°$
  • Range: -360 — 360

Height

The wave height of the regular wave.


  • Default value: 5
  • Unit: $\text{m}$
  • Range: 0 — 100

Period or length based

Choose if the wave period or wave length should be specified. If you choose 'Wave period based' then the wave length is calculated from the period, and vice versa.

Options:

Wave period based (default):

The wave length is calculated from the period.

Wave length based:

The period is calculated from the wave length.

Period

The wave period of the regular wave.



  • Default value: 10
  • Unit: $\text{s}$
  • Range: 0.1 — 1000

Length

The wave length of the regular wave.

This parameter is not shown if the Period or length based parameter is set to Wave length based in which case the wave period is calculated from the length.

  • Default value: 100
  • Unit: $\text{m}$
  • Range: 1 — 10000

Number of coefficients

The number of coefficients to be used. If only 1, then the wave will be a linear wave. 11 is usually enough, and more than 20 is rarely required.

This corresponds to the number of Fourier coefficients that will be used to describe the wave. This is also the number of intervals into which one-half of the wave is divided for computations. See Stream function waves.

  • Default value: 11
  • Unit:
  • Range: 1 — 100

Convergence criterion

Convergence criterion. A lower value yields a more accurate results but increases the computational time.

Within a height step, if the difference between the sum of the magnitudes of all variables at two successive iterations is less than the convergence criterion, the algorithm moves on to the next height step.

If the maximum number of iterations is reached and the difference between the sum of magnitudes is larger than the convergence criterion, the computation is considered as not converged. See Stream function waves

  • Default value: 0.0004
  • Unit:
  • Range: 1e-08 — 0.01

Number of height steps

The number of height steps. More height steps improve convergence but slow down the computation.

For a wave height H, the algorithms starts by solving the equations for a height 0, and then for incremental hieghts until the solution for H is found. For each new step, a linear extrapolation of the solution from the two previous steps is used as an initial condition.
This is useful when the algorithm does not converge: having more height steps allows for an initial condition closer to the final solution. See Stream function waves.

  • Default value: 10
  • Unit:
  • Range: 1 — 100

Max number of iterations

The maximum number of iterations before the algorithm is considered to not have converged. A larger number can help with convergence.

The algorithm uses the Newton method to solve the system of equations. This is an iterative method, and the algorithm is considered not converged when the maximum number of iterations has been reached. See Stream function waves

  • Default value: 20
  • Unit:
  • Range: 1 — 100