The dead water phenomenon. A computational fluid dynamics study

Abstract

Applying the computational fluid dynamics software openFoam, we study dead water resistance on a barge. Dead water resistance is the extra drag due to internal waves in the interface between salt water and fresh water. For Froude numbers below 1.5, we find an inverted U-shape between the Froude number and dead water resistance. Below and above the inverted U-shape range, the dead water resistance is small. The peak in dead water resistance is located in the range Fr 0.6-0.7. The size of dead water drag grows with the ratio of draft to pycnocline. For a draft to pycnocline equal to one, the drag increases by 21 percent due to the internal wave. The k-omega model does not give steady drag coefficients in our simulations. The k-omega SST model gives steady drag coefficients. The dead water drag is to a large degree dependent on the internal wave surface elevation below the stern of the barge. Pressure drag is the main driver behind the dead water drag. The skin friction only contributes positively to the dead water drag for the largest draft to pycnocline ratio, which equals one.