USER MANUAL SWAN Cycle III version 40.72A

90 Appendix A
TM02
Mean absolute wave period (in s) of E(ω,θ), defined as
(∫ ∫ ) ω
T m02 = 2π
2 −1/2 (∫ ∫ )
E(ω,θ)dωdθ
∫ ∫ ω
E(ω,θ)dωdθ
= 2π 2 −1/2
E(σ,θ)dσdθ
∫ ∫ E(σ,θ)dσdθ
DIR
PDIR
TDIR
RTMM10
Mean wave direction (in o , Cartesian or Nautical convention),
as defined by (see Kuik et al. (1988)):
⌊ ∫ ⌋
sin θE(σ,θ)dσdθ
DIR = arctan ∫ cos θE(σ,θ)dσdθ
This direction is the direction normal to the wave crests.
Peak direction of E(θ) = ∫ E(ω,θ)dω = ∫ E(σ,θ)dσ
(in o , Cartesian or Nautical convention).
Direction of energy transport (in o , Cartesian or Nautical convention).
Note that if currents are present, TDIR is different from the mean wave
direction DIR.
Mean relative wave period (in s) of E(σ,θ), defined as
∫ ∫ σ
RT m−10 = 2π
−1 E(σ,θ)dσdθ
∫ ∫ E(σ,θ)dσdθ
RTM01
This is equal to TMM10 in the absence of currents.
Mean relative wave period (in s) of E(σ,θ), defined as
(∫ ∫ ) −1
σE(σ,θ)dσdθ
RT m01 = 2π ∫ ∫ E(σ,θ)dσdθ
RTP
TPS
PER
This is equal to TM01 in the absence of currents.
Relative peak period (in s) of E(σ) (equal to absolute peak period
in the absence of currents).
Note that this peak period is related to the absolute maximum bin of the
discrete wave spectrum and hence, might not be the ’real’ peak period.
Relative peak period (in s) of E(σ).
This value is obtained as the maximum of a parabolic fitting through the
highest bin and two bins on either side the highest one of the discrete
wave spectrum. This ’non-discrete’ or ’smoothed’ value is a better
estimate of the ’real’ peak period compared to the quantity RTP.
Average absolute period (in s) of E(ω,θ), defined as
∫ ∫ ω
T m,p−1,p = 2π
p−1 E(ω,θ)dωdθ
∫ ∫ ω p E(ω,θ)dωdθ
The power p can be chosen by the user by means of the QUANTITY