Terminology

Term

Definition

Added Mass

A(\omega)

BEM

Boundary Element Method

BEMIO

Boundary Element Method Input/Output

BS

Bretschneider Wave Spectrum

$CASE

WEC-Sim case directory

Heave (Z)

Motion along the Z-axis

JS

JONSWAP Spectrum

Pitch (Ry)

Rotation about the Y-axis

PM

Pierson-Moskowitz Specturm

PTO

Power Take-Off

Radiation Damping

B(\omega)

Roll (Rx)

Rotation about the X-axis

$WECSIM

WEC-Sim source code directory

Surge(x)

Motion along the X-axis

Sway (Y)

Motion along the Y-axis

Wave Excitation

F_{exc}

Yaw (Rz)

Rotation about the Z-axis

Variables

Variable

Definition

A(\omega)

Frequency dependent radiation added mass (kg)

A_{\infty}

Added mass at infinite frequency (kg)

B(\omega)

Frequency dependent radiation wave damping (N/m/s)

C_{a}

Morison element coefficient of added mass

C_{d}

Quadratic drag coefficient

C_{m}

Mooring damping matrix (N/m/s)

C_{pto}

PTO damping coefficient (N/m/s)

C_{v}

Linear (viscous) damping coefficient (N/m/s)

\eta

Incident wave (m)

f

Wave frequency (Hz)

F_{B}

Net buoyancy restoring force (N) or torque (N.m)

F_{exc}

Wave excitation force (N) or torque (N.m)

F_{rad}

Wave radiation force (N) or torque (N.m)

F_{pto}

Power take-off force (N) or torque (N.m)

F_{me}

Morison element force (N) or torque (N.m)

F_{v}

Damping or friction force (N) or torque (N.m)

F_{m}

Mooring connection force (N) or torque (N.m)

g

Gravity (m/s/s)

h

Water depth (m)

H

Wave height (m)

H_{s}

Significant wave height, mean wave height of the tallest third of waves (m)

H_{m0}

Spectrally derived significant wave height (m)

k

Wave number (rad/m), k = \frac{2\pi}{\lambda}

K_{hs}

Linear hydrostatic restoring coefficient (N/m)

K_{m}

Mooring stiffness matrix (N/m)

K_{pto}

PTO stiffness coefficient (N/m)

\lambda

Wave length (m)

m

Mass of body (kg)

m_k

Spectral moment of k, for k = 0,1,2,…

\omega

Wave frequency (rad/s), \omega = \frac{2\pi}{T}

\phi

Wave phase (rad)

R_{f}

Ramp function

\rho

Water density (kg/m3)

t

Simulation time (s)

t_{r}

Ramp time (s)

\theta

Wave direction (Degrees)

T_{p}

Peak period (s)

X

Translation and rotation displacement vector (m) or (rad)