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Relative Rotative Efficiency - Coggle Diagram
Relative Rotative Efficiency
Open water efficiency
\( \eta_o= \dfrac{TV_A}{2 \pi n Q_0} \)
Incógnitas
Q0 - Torque in open water
T - Thrust
n - revolutions
VA - Propeller speed of advance
eta cu = Te Vi Arrombada sobre 2 pica Nao Qero
Efficiency behind the hull
\( \eta_B= \dfrac{TV_A}{2 \pi n Q} \)
Incógnitas
Q - Torque behind hull
T - Thrust
n - revolutions
VA - Propeller speed of advance
Relative Rotative Efficiency
\( \eta_R=\dfrac{\eta_B}{\eta_0} = \dfrac{Q_0}{Q} \)
Difference due to
wake
Values
Single Screw
BTW 1,0 and 1.1
Twin Screw
BTW 0.95 and 1.0