We present an immersed array of four rotors whose promoted flow can be mathematically modeled with a creeping flow solution from the incompressible Navier-Stokes equations. We show that this solution is indeed represe...We present an immersed array of four rotors whose promoted flow can be mathematically modeled with a creeping flow solution from the incompressible Navier-Stokes equations. We show that this solution is indeed representative of the two-dimensional experiment and validate such class of solution with experimental data obtained through the Particle Image Velocimetry technique and time-lapsed particles visualizations.展开更多
Accurately predicting the power saving from wind-assisted ship propulsion is one of the most discussed topics in alternative and complementary propulsion methods.Aero-and hydrodynamic interactions between the sails an...Accurately predicting the power saving from wind-assisted ship propulsion is one of the most discussed topics in alternative and complementary propulsion methods.Aero-and hydrodynamic interactions between the sails and the ship increase the difficulty of modelling the propulsion contribution theoretically,but the sensibility of sail performance on the wind conditions increases the demands on measurement accuracy if the performance is to be measured in sea trials.This paper analyses and compares the uncertainties of sea trial tests and model predictions by means of parameter variation and Monte Carlo simulations.The results show that sea trials have an uncertainty of 23%,well above 100%of the measured savings,if performed using normal onboard equipment.Model uncertainties were found to be between 6%and 17%of the predicted savings.展开更多
文摘We present an immersed array of four rotors whose promoted flow can be mathematically modeled with a creeping flow solution from the incompressible Navier-Stokes equations. We show that this solution is indeed representative of the two-dimensional experiment and validate such class of solution with experimental data obtained through the Particle Image Velocimetry technique and time-lapsed particles visualizations.
文摘Accurately predicting the power saving from wind-assisted ship propulsion is one of the most discussed topics in alternative and complementary propulsion methods.Aero-and hydrodynamic interactions between the sails and the ship increase the difficulty of modelling the propulsion contribution theoretically,but the sensibility of sail performance on the wind conditions increases the demands on measurement accuracy if the performance is to be measured in sea trials.This paper analyses and compares the uncertainties of sea trial tests and model predictions by means of parameter variation and Monte Carlo simulations.The results show that sea trials have an uncertainty of 23%,well above 100%of the measured savings,if performed using normal onboard equipment.Model uncertainties were found to be between 6%and 17%of the predicted savings.
