Papers by Keyword: Hydrodynamic Force

Abstract: Wave glider harvests the abundant ocean wave energy for long term ocean cruising due to its particular two-part architecture. Its submerged part named glider converts vertical fluctuation of waves to horizontally forward propulsion. Because of the uncertainty of the ocean condition and irregularity of its wave motion, the design parameters of the submerged glider vary in a confined range in the state of art design models. In order to indicate the hydrodynamic characteristics and summarize the dynamic law of the submerged glider with different design parameters, this paper concentrates on three critical design details: profile of the wings, interval space of the arrayed multiple flapping wings and maximum rotating angle of wings, and performs the corresponding CFD analysis. Finally, we conclude that the lift curve of NACA0006 and plate profile is almost the same with small waves at sea, but NACA0006 profile can generate much larger forward lift than the plate profile with seawater velocity up to 0.5m/s; Decreasing space of intermittent causes more obvious decrement of forward lift while space of intermittent overpasses the inflection point at 20cm; With the decrement of the maximum rotating angle, the forward lift occurs to take a sharp decline if the angle strides the inflection point.

Abstract: In this paper, Based on the research of CFD basic theory and several key technologies, the numerical model for solving three-dimensional flow field around the open water rudder is proposed. And with the help of computing platform FLUENT, several kinds of numerical simulation of maneuverable movement of NACA0015 rudder have been done. The numerical results are compared with experimental results, showing that the CFD model which is proposed in this paper is suitable for computation of hydrodynamic forces and simulation of the viscous flow around the open water rudder.

Abstract: In the initial operation stage of some ore wharf, the silting situation appears in the wharf apron; through the on-spot hydrological, geological and topographic survey and combination with a lot of previous data and the project implementation, the research is made into the hydrodynamic sediment conditions in the water area and the changes of topographic erosion and siltation. The analysis shows that the siltation is related to many factors, including: the natural siltation effect, the effect of erosion adjustment period, the effect of sand excavation and dredging, and the effect of wharf construction. Among which, the local excavation in the rear of the wharf under construction has a great effect on the siltation of the wharf apron.

Abstract: Unstable motion is characteristics of tugboat for retarding a large vessel. It will make the capabilities of tugboat’s braking force vary. In this paper, we used an ASD-tugboat model to measure the yaw and sway amplitudes and the braking force when the tugboat model is towing on a line. In addition, we still had carried out the tests of hydrodynamic forces acting on the tugboat model. Finally, we confirmed that the yaw and sway motion was existed and the tugboat’s braking performance was affected by the unstable motion.

Abstract: It is easy to generate the separation of the flow in the stern when the ship is in oblique motion, and the flow around the hull is complex. In this article, the viscous flow around a tank in oblique motion is simulated using viscous method, and the maneuvering hydrodynamic forces are calculated and compared with experimental results. It is shown that the present method of the numerical simulation is feasible.

Abstract: To protect downstream of hydraulic structures against erosion and degradation, must dipress water energy. one of the most comon methods to achive this purpose is constructing the stilling basin at the downstream of such structures. In stilling basin, the water energy dissipated by taking place of hydraulic jump. When a hydraulic jump occurs, the hydrodynamic and hydrostatic forces effect on the stilling basin floor slab. These forces include the force due to water weight and the up lift force affected the slab below which these forces are classified in hydrostatic. also the other force is hydrodynamic force due to pressure fluctions below the hydraulic jump. To keep the stilling basin stabillity from liffting up and destruction must the resistant forces be equal to destroyer forces. In this study after discution about the hydraulic jump and its resultant forces, a equation has been offerd to determine the thickness of stilling basin floor slab using buckingham theory andsoftware DATAFIT. Finaly the slab which evaluated by physical model, simulated using mathematical model(software ANSYS 10) and studied. The stress and strain diagrams were extracted. Results showed that physical and mathematical models were matched very good.

Abstract: On the basis of the potential fluid theory, the effect of hydrodynamic force on the dynamic response of a typical rectangular solid pier as prototype was analyzed at different water depths under two types of seismic waves. At the same time, the distribution of the hydrodynamic pressure, the action spot of the hydrodynamic force and the effect of fluid on the seismic response of the piers were analyzed in seismic waves. The results include the vibration period, the peak of displacement, shear and moment of pier are increased as the rise of water depth. The effect of fluid on the dynamic response of pier should not be ignored. The influence of different seismic loads on the distribution of hydrodynamic pressure is not identity.