Test Case 1b.2:Static Drift

Conditions

• Towing condition in still water
  
• Pitch and heave free; roll fixed
  
• With rudder
  
• With Propeller

$F_n$ [-]	$R_n$ [-]	$L_{PP}[m]$	$U_c$ [m/s]	$n$ [rps]	$\beta$ [deg]	$\delta$ [deg]
$0.142$	$4.6 \times 10^6$	$5.52$	$1.047$	$8.59$	$12.0$	$0.0$

Items and Remarks

Items	Remarks
Integral variables: Non-dimensionalized coefficients of X-force ($X'$) Y-force ($Y'$) Yaw-moment ($N'$) Thrust force ($T'_x$) Rudder X-force ($R'_x$) Rudder Y-force ($R'_y$) and Uncertainty analysis ( $U_{SN}, U_V, E$ )	Experimental results are available

• Coordinate system for comparisons is fixed to midship on the undisturbed water plane. ( see Figure 1)
  
• Froude number $F_n$ and Reynolds number $R_n$ are defined using towing carriage speed ( $U_c$ ) and length between perpendiculars ( $L_{PP}$ ):

  $$F_n = \dfrac{U_c}{\sqrt{g \cdot L_{PP}}}, \quad R_n = \dfrac{U_c \cdot L_{PP}}{\nu}$$

  
  
  where $g$ is the gravitational acceleration and $\nu$ is the kinematic viscosity.
  

• $n$ is the propeller revolution rate [rps] and $\beta$ and $\delta$ are drift angle [deg] and rudder angle [deg], respectively.
  

• All CFD predicted force coefficients should be reported using the provided ship length $L_{PP}$, mean draft $T_m$ and ship speed $U$. Force coefficients are defined as follows:

  $$X' = \dfrac{X}{\frac{1}{2} \rho U^2 L_{PP} T_m}, \quad Y' = \dfrac{Y... ...\rho U^2 L_{PP} T_m}, \quad N' = \dfrac{N}{\frac{1}{2} \rho U^2 L_{PP}{}^2 T_m}$$

  $$T'_x = \dfrac{T}{\frac{1}{2} \rho U^2 L_{PP} T_m}, \quad R'_x = \dfrac... ...\rho U^2 L_{PP} T_m}, \quad R'_y = \dfrac{Y_R}{\frac{1}{2} \rho U^2 L_{PP} T_m}$$

  
  
  where $N'$ is the yaw-moment around the origin of the coordinates.
  

Figure 1: Coordinate system for hydrodynamic forces and moment