BOLLARD PULL OF BARGE WITH CARGO
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TOWING RESISTANCE FORCE CALCULATION
The aim of this calculation is to perform the analysis of the barge total resistance force during the cargo transportation.
The global system (barge & jacket & ballast) is considered with different towing speeds, and the total resistant force is evaluated. The total tow resistance is the sum of the following contributions:
WAVE DRIFT FORCE
The calculation of the wave drift force is based on DNV guidelines for marine transportation
RESISTANCE DUE TO TOWING IN CALM WATER
The resistance due to drag friction fluid velocity is evaluated based on the following “Morison”formula:
ADDITIONAL RESISTANCE DUE TO WIND AND CURRENT
The drag resistance is computed according to the following formula: F drag = ½ * ρ * C * S * (V ²TOT - V ² FS), with VTOT the total speed, including the induced speed due to towing velocity (VFS),and the additional speed.
TOTAL TOW FORCE
Additional wind for transit and extreme conditions is considered facing the convoy. Total resistance can be calculated as
Ftot = Fdrag + Fdrift + F calm water
The aim of this calculation is to perform the analysis of the barge total resistance force during the cargo transportation.
The global system (barge & jacket & ballast) is considered with different towing speeds, and the total resistant force is evaluated. The total tow resistance is the sum of the following contributions:
- Added resistance in wave due to wave drift,
- Calm water resistance (drag + wave making),
- Resistance due to wind and current,
- Additional wind and current effect (fwd speed).
WAVE DRIFT FORCE
The calculation of the wave drift force is based on DNV guidelines for marine transportation
RESISTANCE DUE TO TOWING IN CALM WATER
The resistance due to drag friction fluid velocity is evaluated based on the following “Morison”formula:
ADDITIONAL RESISTANCE DUE TO WIND AND CURRENT
The drag resistance is computed according to the following formula: F drag = ½ * ρ * C * S * (V ²TOT - V ² FS), with VTOT the total speed, including the induced speed due to towing velocity (VFS),and the additional speed.
TOTAL TOW FORCE
Additional wind for transit and extreme conditions is considered facing the convoy. Total resistance can be calculated as
Ftot = Fdrag + Fdrift + F calm water
