On the basis of oblique towing tests and flow visualizations of ship models, the flow pattern around a high-speed transom-stern ship, its motion attitudes (sinkage and trim) and the characteristics of hydrodynamic for...On the basis of oblique towing tests and flow visualizations of ship models, the flow pattern around a high-speed transom-stern ship, its motion attitudes (sinkage and trim) and the characteristics of hydrodynamic forces are analysed. It is concluded that the variation of ship motion attitudes, caused by ship speed, has a great influence over the coefficients of hydrodynamic forces and moments acting on the oblique running ship. Ship attitudes related to different speed and drift angles are calculated by Hess-Smith method. By distributing complex singularities over the surface of a double model and by considering separated vortex sheets in the wake at the lee side of the model, pressures and velocities of the fluid around the model may be calculated directly by solving a three-dimensional body with lift problem. The transom stern stream-lines are extended to form a virtual length. In this way, the hydrodynamic lateral forces, yaw moments and pressure distribution are calculated. The results show good agreement with those measured from model tests.展开更多
A finite volume method is employed to predict the turbulent flow in irregular domains. In handling the irregular solution domain an algebraic nonorthogonal transformation along with the orthogonal body-surface coordin...A finite volume method is employed to predict the turbulent flow in irregular domains. In handling the irregular solution domain an algebraic nonorthogonal transformation along with the orthogonal body-surface coordinate is presented, which avoids the task of numerically generating the grid and also extends the scope of solution domain as compared with that of [1]. The modified K-Ε turbulence model is adopted to account for the Coriolis force caused by the system rotation. Three examples with or without rotation effects are presented.展开更多
The in-line and lift forces on bipiles in tandem array induced by both irregular waves and currents were investigated experimentally in this paper. The characteristics in both time and frequency domain of inline, lift...The in-line and lift forces on bipiles in tandem array induced by both irregular waves and currents were investigated experimentally in this paper. The characteristics in both time and frequency domain of inline, lift and resultant forces as well were analyzed. The grouping effect coefficients of in-line and resultant forces on two piles related to KC number and relative spacing parameters are given. A comparison of the magnitude and direction of resultant forces on bipiles in tandem array with the corresponding values for single cylinder is also made.展开更多
文摘On the basis of oblique towing tests and flow visualizations of ship models, the flow pattern around a high-speed transom-stern ship, its motion attitudes (sinkage and trim) and the characteristics of hydrodynamic forces are analysed. It is concluded that the variation of ship motion attitudes, caused by ship speed, has a great influence over the coefficients of hydrodynamic forces and moments acting on the oblique running ship. Ship attitudes related to different speed and drift angles are calculated by Hess-Smith method. By distributing complex singularities over the surface of a double model and by considering separated vortex sheets in the wake at the lee side of the model, pressures and velocities of the fluid around the model may be calculated directly by solving a three-dimensional body with lift problem. The transom stern stream-lines are extended to form a virtual length. In this way, the hydrodynamic lateral forces, yaw moments and pressure distribution are calculated. The results show good agreement with those measured from model tests.
文摘A finite volume method is employed to predict the turbulent flow in irregular domains. In handling the irregular solution domain an algebraic nonorthogonal transformation along with the orthogonal body-surface coordinate is presented, which avoids the task of numerically generating the grid and also extends the scope of solution domain as compared with that of [1]. The modified K-Ε turbulence model is adopted to account for the Coriolis force caused by the system rotation. Three examples with or without rotation effects are presented.
文摘The in-line and lift forces on bipiles in tandem array induced by both irregular waves and currents were investigated experimentally in this paper. The characteristics in both time and frequency domain of inline, lift and resultant forces as well were analyzed. The grouping effect coefficients of in-line and resultant forces on two piles related to KC number and relative spacing parameters are given. A comparison of the magnitude and direction of resultant forces on bipiles in tandem array with the corresponding values for single cylinder is also made.
