Case 2.3b

Conditions:

• Self propelled at model point in calm water

• With rudder

• FR_zθ

• Re = 6.52×10⁶, Fr = 0.26

References:

Not yet available

Requested computations

The self propulsion computation is to be carried out at the model point following the experimental procedure. Thus, the rate of revolutions of the propeller n is to be adjusted to obtain force equilibrium in the longitudinal direction: T = R_T(SP)

Report rate of revolutions n, thrust and torque coefficients K_T, K_Q and resistance components CT_(SP), CP_(SP), CF_(SP).

In case this procedure cannot be carried out, set n to the measured value 14.15 rps and report towing force (R_T(SP)-T), K_T, K_Q, CT_(SP), CP_(SP), CF_(SP).

Items and remarks

Table/ Figure #	Item	EFD Data		Submission Instruction
		Data file	Image	Table file	Sample
2.3b-1	V&V of- Requested values: n, KT, KQ, CT(SP), CP(SP), CF(SP), sinkage (σ) and trim (τ) or ( for given n ) ( RT(SP)-T ), KT, KQ, CT(SP), CP(SP), CF(SP), sinkage (σ) and trim (τ)	Refer to sample file for details		Filename: [Identifier]_V&V_2-3b.xls (Excel file)	[Identifier]_V&V_2-3b.xls

Note: a positive (+) sinkage value is defined upwards and a positive (+) trim value is defined bow up.

Submission Instructions:

· [Identifier] should be [Institute Name]-[Solver Name]. For example, if your institute is Chalmers and solver is SHIPFLOW4.2, identifier should be Chalmers-SHIPFLOW4.2

V&V:

1.  Resistance coefficients are based on wetted surface area (S/L²) =0.1803 with rudder for static orientation in calm water.

2. Comparison Error, E%D=(D-S)/D×100, where D is the EFD value, and S is the simulation value. 

3. Relative change in solution: ε₁₂%S₁ = |(S₁-S₂)/S₁|×100, "1" refers to the finest grid.

4. Iterative uncertainty U_I is based on fine grid solution.

5. is the theoretical order of accuracy = order of convection scheme.

6. U_G is the grid uncertainty. is the simulation numerical uncertainty.

7. U_D is the data uncertainty.

8. is the validation uncertainty.

9. Brief details of the V&V method should be provided in the paper (including the determination of U_I ).

All quantities are non-dimensionalized by density of water (), ship speed (U), and length between perpendiculars (L_pp):

,

• where g is the gravitational acceleration and ν is the kinematic viscosity.

· All CFD predicted force coefficients should be reported using the provided wetted surface area at rest (S₀). Force coefficients are defined as follows:

Symbols:

D Diameter of propeller [m]

d_h Diameter of a propeller hub, D × (Hub ratio) [m]

K_T Thrust coefficient,

K_Q Torque coefficient,

n Propeller rate of revolution [rps]

Q Propeller torque [Nm]

R_T(SP) Total resistance in self-propelled condition [N]

SFC Skin friction correction [N]

T Propeller thrust [N]

U Ship speed [m/s]