Research on a Ship Deflection Anti-Collision Method Based on a Water-Jet Interference Flow Field

Abstract

Currently, water jets are mainly used in the fields of mechanical processing and mining collection. This paper creatively introduces them to the field of safety assurance for inland navigation. Compared with the traditional bridge anti-striking methods such as intelligent early warning and passive anti-striking, this method can form an “interference zone” by changing the water flow conditions in the local bridge water areas, causing the yawing moment of the yaw ship to change, thereby causing the ship’s course to change, and thus guiding the ship to move away from the bridge pier to realize active anti-striking of the ship. In this paper, a combination of generalized model testing and numerical simulation was used to study the effects of different nozzle pressures and different ship pier distances of the water-jet generator on the trajectory and drift angle of the stalled ship. The results showed that the numerical simulation was in good agreement with the model test results. Within the interference zone, the distance between the ship and the pier increased rapidly after the action of the disturbance zone to 9.1, 5.8, and 6.2 times the ship’s width, respectively, reaching a safe distance. During the process of being affected by the interference zone, the maximum drift angle of the yaw ship was less than 20°, the course of the ship was generally stable, and the drift angle comparison error was a maximum of 10.6%, a minimum of 3.5%, and an average error of 6.7%. A negative peak and a positive peak of four times the absolute value of the negative peak occurred in the yaw-moment ephemeral curve during the ship’s passage through the interference area. The method had a notable effect on the anti-striking of stalled ships and two invention patents applied for in the course of research.

Research on the Hydraulic Characteristics of Active Ship Collision Avoidance Devices for Hydrodynamic High-Energy Beam Bridges under Relatively Optimum Deployment Conditions

“…However, these intelligent warning systems only have an effect on ship yaw resulting from specific factors. If the intelligent warning system fails to warn a ship effectively, passive collision avoidance devices are still needed to ensure the safety of the bridge [20]. Once a ship bridge collision occurs, it affects the normal navigation of the waterway and can even cause major bridge damage and negative societal impacts.…”

“…This reduced the risk of the ship hitting the collision avoidance devices and causing damage to the ship, enhancing the safety of the navigable sections of the river and the bridge [19] In this study, a bridge in the Jialing River basin was taken as the engineering background, and a typical ship in a navigable river section was taken as the research object. To prove the effectiveness of the device [20], numerical simulations and generalized model tests were carried out using a Fluent overset grid [22,23] technology and RNG k-ε turbulence model [24,25] to explore the reasonable deployment angle of the device and clarify the optimal jet ratio of the device, R. Finally, by comparing the optimal jet ratio and the difference of the ship's motion and response state at the reasonable deployment angle, we area, a hydraulic high-energy beam device in the intervention zone was set on the side of the bow of the vessel to change the shipʹs direction and ensure active collision avoidance. This reduced the risk of the ship hitting the collision avoidance devices and causing damage to the ship, enhancing the safety of the navigable sections of the river and the bridge [19] In this study, a bridge in the Jialing River basin was taken as the engineering background, and a typical ship in a navigable river section was taken as the research object.…”

“…This reduced the risk of the ship hitting the collision avoidance devices and causing damage to the ship, enhancing the safety of the navigable sections of the river and the bridge [19] In this study, a bridge in the Jialing River basin was taken as the engineering background, and a typical ship in a navigable river section was taken as the research object. To prove the effectiveness of the device [20], numerical simulations and generalized model tests were carried out using a Fluent overset grid [22,23] technology and RNG k-ε turbulence model [24,25] to explore the reasonable deployment angle of the device and clarify the optimal jet ratio of the device, R. Finally, by comparing the optimal jet ratio and the difference of the ship's motion and response state at the reasonable deployment angle, we In this study, a bridge in the Jialing River basin was taken as the engineering background, and a typical ship in a navigable river section was taken as the research object. To prove the effectiveness of the device [20], numerical simulations and generalized model tests were carried out using a Fluent overset grid [22,23] technology and RNG k-ε turbulence model [24,25] to explore the reasonable deployment angle of the device and clarify the optimal jet ratio of the device, R. Finally, by comparing the optimal jet ratio and the difference of the ship's motion and response state at the reasonable deployment angle, we provided a basis for the research and development of safe, efficient, and green collision avoidance technology and equipment for ships and bridges.…”