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In hydro-driven ship lifts, plunger valves and fixed cone valves are the most suitable structures for achieving accurate flow control under a wide range of flow conditions. In order to inhibit cavitation in these valve structures, experiments were conducted in which forced aeration was applied before the valve. The cavitation phenomena and aerated flow regime were observed through a transparent glass pipe, and the cavitation noise characteristics were recorded using a hydrophone. The test results show that aeration can reduce the valve working cavitation number, albeit to a limited degree (<5%). Based on the sound velocity theory of aerated flow and the experimental results, the relationship between the aeration concentration and the cavitation inhibition efficiency was obtained. When the aeration concentration is approximately 0.1%, cavitation can be significantly inhibited via forced aeration before the valve. Once the aeration concentration reaches 0.9%, the cavitation inhibition efficiency becomes saturated. The research results presented in this paper provide a reference for the cavitation inhibition of industrial valves. [ABSTRACT FROM AUTHOR]

Geotechnical engineering in the construction of the new Niederfinow ship lift The new Niederfinow ship lift on the Havel‐Oder waterway bridges a change in terrain elevation of 36 m and connects a plateau with predominantly cohesive soil with the Oderbruch, where mainly non‐cohesive sediments are overlaid by cohesive and organic layers. The subsoil consists mainly of glacial soils (glacial till, meltwater and basin sediments). Additionally tertiary soils in deeper areas (tertiary sands, clays and silts as well as carbonaceous formations) and near‐surface postglacial soils (holocene sands and silts as well as mud and peat) are present. The ship lift will be placed in a 13 m, in some areas up to 16 m deep excavation pit, consisting of a combined wall tied back using only one layer of ground anchors and an underwater concrete floor secured against uplift by GEWI piles within the non‐cohesive sediments. Due to the small allowable deformations of the ship lift in comparison to a lock, special attention was paid to the settlement behaviour. For this purpose, extensive numerical analyses were carried out before and during construction in order to compare the results with the deformations measured during construction. In addition, extensive earthworks were carried out on high and steep embankments with corresponding construction requirements and compaction control as well as geohydraulic investigations. [ABSTRACT FROM AUTHOR]

Corrosion protection of the new ship lift Niederfinow: durability of the colour and cathodic protection For the corrosion protection for the new Niederfinow ship lift, questions concerning the durability of the colour of the coating and the cathodic corrosion protection had to be solved. Colour consistency and accuracy have rarely been considered in quality control of similar structures such as steel bridges. Coloured areas on such buildings often chalk and fade over time and no longer meet the architectural requirements. The blue and yellow colour shades of the coatings acc. to Blatt 94 used at Niederfinow deviated from the required colour stability. When evaluating the deviations, it was important to select the underlying colour system appropriately. In this case, the ΔECMC system was ultimately chosen as the evaluation basis for the yellow colour. Other reasons for colour differences were the processing conditions and a batch change of the coating material. If there are increased requirements for colour stability, e. g. for architecturally significant areas, coatings with particularly colour‐stable pigments should be used. These should be examined in advance by field tests. Cathodic protection was provided by galvanic anodes and an impressed current system. It turned out that, especially with complex systems like this one, mobile measurements during construction should be carried out to compare the target and actual potential. [ABSTRACT FROM AUTHOR]

Launching-type ship lifts are commonly used in navigational mountain rivers to realize river channelization and communicate different water systems. However, the complicated water–gas–solid coupling process incurred during the water exit of cavities beneath a ship chamber can strongly affect the stability of the chamber and even affect the ship lift operation. In this study, the water exit behavior of a generalized cavity model was investigated using an experimental–numerical approach. Both the air pressure and flow patterns during the water exit process were analyzed. The results demonstrate three different types of air pressure process in cavity exits. Based on the results, a series of relationships are proposed to predict the maximum negative pressure incurred in the water exit process. Moreover, a method was developed to determine the optimum ported area of the cavity regarding the absence of additional hydrodynamic loads. Furthermore, a classification system to typify the flow patterns manifesting in the cavity is proposed. It was found that the transition from a slug flow to a drop flow could be determined as a transition coefficient K equal to 1. [ABSTRACT FROM AUTHOR]

Water-level fluctuation is a crucially important hydraulic factor to meet the safety of ship navigation. Due to the uncertainty and evolution of the maximum amplitude of water-level variation in the approach channel, the river reach between two dams located along the Yangtze River in China is selected as a study area and the impact of various operating conditions of the cascade hydro-plant on the maximum amplitude of water-level variation at typical sites is revealed combining the orthogonal test method and a hydrodynamic model. In addition, the critical threshold for the water-level variation at the lower lock head of the ship lift is explored using maximum entropy method. Results demonstrate that flow variation and regulation time are the most prominent factors affecting water-level fluctuation at the lower lock head of the ship lift, and the existing standard (0.5 m within 1 h and 0.3 m within 30 min) for controlling the maximum variation in water level at the lower lock head of the ship lift is reasonable and more safety oriented. This study provides a novel perspective to understand the response of water-level fluctuation to the stochasticity of operating conditions for the cascade hydropower stations. HIGHLIGHTS A one-dimensional hydrodynamic model was developed for validating the water-level fluctuation in the approach channel based on a physics model test.; Using orthogonal array design method to address the intricate scenarios from the dual cascade hydropower stations.; Using maximum entropy method (MEM) to examine the maximum water-level variation under the operation of large-scale cascade hydropower stations.;

Ships docking and traveling in a branched lower approach channel system are at risk from surges caused by multi-lane locks during emptying operations. For this reason, water-level variations in the lower approach channel in response to discharge, interval running time, and outlet location of lock operations were studied using a 2-D hydrodynamic model validated by physical model tests, and the impact of water level variation on navigation safety under extreme operation scenarios of a quadruple-lane lock group was identified. Results indicated that discharge and interval running time of lock emptying had the greatest impact on the water level variation at the lock head. Water level variation at the lower lock head of the ship lift exhibited a trend of first decreasing and then increasing with the increment of the discharge from the lock chamber into the outer river. Specifically, the surge height at the lock head of the ship lift reached the minimum when approximately 40% of the discharge generated by dual-lane locks during emptying operations was released into the outer river. Overall, the simultaneous operation of quadruple-lane lock group and unit load rejection should be avoided in engineering applications. HIGHLIGHTS A 2-D hydrodynamic model was utilized to analyze the water-level fluctuations in a branched approach channel system.; Water-level fluctuations in response to discharge, interval running time, and emptying outlet location of lock operations were revealed in details.; Extreme multi-lane lock operating scenarios were determined considering the requirement of safe docking of ships at the lower lock head of the ship lift.;

Accurately estimating the ship's approach angle is crucial during berthing, or passing through navigational structures. It forms the foundation for ship navigation decisions. This study introduces the LiDAR point cloud-based ship pose perception network (PP-Net), a novel deep learning-based method for acquiring ship approach angles. Addressing the challenge of manually annotating approach angles, the ship pose perception method based on point cloud feature distribution (FD) was proposed to obtain initial angle estimates. The max-pooling function was utilized to address the disorder of point clouds, and a multi-resolution feature extractor was employed to enhance the network's robustness in extracting features from inconsistently dense point clouds. By using iterative farthest point sampling (IFPS), datasets with varying numbers of point clouds were standardized to a fixed number of points, thereby normalizing input dimensions and improving computational efficiency. Additionally, a novel loss function was proposed to improve the model's predictive accuracy. Experimental validation conducted in the scenario of ships entering ship lifts demonstrates the effectiveness of the proposed method. The outcomes can support safe navigation for ships in restricted waterways. • Proposed a ship pose perception method based on point cloud feature distribution. • Introduced PP-Net, a deep learning-based method for estimating ship approach angles. • Developed a novel loss function to enhance the model's predictive accuracy. • Validated the method in ship lift scenarios, demonstrating its effectiveness. [ABSTRACT FROM AUTHOR]

In hydro-driven ship lifts, plunger valves and fixed cone valves are the most suitable structures for achieving accurate flow control under a wide range of flow conditions. In order to inhibit cavitation in these valve structures, experiments were conducted in which forced aeration was applied before the valve. The cavitation phenomena and aerated flow regime were observed through a transparent glass pipe, and the cavitation noise characteristics were recorded using a hydrophone. The test results show that aeration can reduce the valve working cavitation number, albeit to a limited degree (

There is growing interest in the lock group co-scheduling research because of serious capacity imbalance between two dams at Three Gorges-Gezhou Dams Hub (TGDH). However, most current studies ignore the impact of ship lift and approach channel on navigation efficiency, and the energy consumption from vessels on ecological environment. Encouraged by this, we investigate an energy-efficient lock group co-scheduling problem at the TGDH with the consideration of ship lift as well as approach channel. A new multi-objective model for the problem is proposed, aiming to simultaneously optimize the average area utilization of all locks, average tardiness of vessels and total energy consumption of vessels. A collaborative adaptive multi-objective algorithm (CAMOA) is well-designed to solve the studied problem. The CAMOA makes use of a well-tailored two-layer encoding scheme and a three-stage group-shift decoding approach to represent and decode each solution. Next, an adaptive adjustment search strategy based on step control factor is periodically triggered to reinforce local exploitation capability, where a novel fuzzy correlation entropy analysis is coupled to evaluate the neighborhood solutions. Extensive simulation experiments are implemented according to the real-world data from the TGDH. The statistical results demonstrate that the proposed CAMOA is efficient and reliable in solving the studied problem. This work is very significant for TGDH to improve the passing efficiency and reduce the energy consumption. [ABSTRACT FROM AUTHOR]

The rack test device for the Three Gorges ship lift is mainly composed of four parts: driving gearbox,driving gear-rack,loading gear-rack and loading gearbox. In order to better calculate and analyze the transmission efficiency of the rack test device,through the establishing gearbox transmission efficiency calculation model,transmission efficiencies of the four parts and the transmission efficiency and the power consumption of the total whole unit are calculated respectively,the calculation results are contrastive analyzed by the input speed and torque,output speed and torque of the test data,the accuracy of calculation model and test data is verified,the research basis of transmission efficiency of gearbox and gear rack for low speed and load duty is established.

• A green co-scheduling problem of ship lift and ship lock is studied. • A new multi-objective mathematical model is proposed for this problem. • The synchronous moving process of vessels is considered. • An effective discrete multi-objective artificial bee colony (DMOABC) algorithm is developed. • Results confirm the effectiveness of the proposed DMOABC. This paper investigates a multi-objective green co-scheduling problem of ship lift and ship lock (GCP-SL&SL) at the Three Gorges Cascade Hub (TGCH). A mathematical model of GCP-SL&SL with objectives of the average utilizations rate of the lock chamber, average waiting time and total energy consumption of vessels, is proposed by separating it into three sub-problems: the facility assignment, lockage assignment and lockage operation scheduling. To solve this problem, a discrete multi-objective artificial bee colony (DMOABC) algorithm is developed. Within the DMOABC, a two-dimensional matrix encoding scheme is designed to encode and a group right-shift decoding scheme is specifically proposed to decode each food source. Then, a novel fitness evaluation mechanism based on fuzzy relative entropy is introduced to hand this multi-objective problem. Next, the food sources are improved from three aspects: (1) the employed bee phase uses new evolutionary operators for fast local search; (2) the onlooker bee phase adopts a modified tabu search for strong global search; (3) the scout bee phase embeds chemical reaction optimization for disturbing population. Finally, extensive experiments are conducted with the real data from historical traffic at TGCH. The results demonstrate our proposed algorithm is significantly better at solving the GCP-SL&SL than other five well-known multi-objective algorithms. The effect analysis under different scenarios indicates that the average waiting time of vessels at the dam is greatly reduced because of considering the synchronous moving process. [ABSTRACT FROM AUTHOR]

Based on the dynamic characteristics obtained with a three-dimension finite element method, a reduced mechanical model and parameters for the ship lift can be modified and obtained. Simulated analysis shows that the reduced mechanical model can adequately represent the dynamic characteristics of the ship lift. The wind-induced vibrations and seismic responses of the structure were calculated respectively. A fuzzy semi-active control strategy for seismic response reduction using a magnetorheological damper was presented. A roof intelligent isolation system was also proposed. Simulation analysis results show that the fuzzy semi-active control with a magnetorheological smart damper is beneficial in suppressing the seismic whiplash effect on the top workshop and confirm that the fuzzy semi-active control strategy is valid in this scenario. [ABSTRACT FROM AUTHOR]

The Three Gorges Project (TGP) ship lift employs 4 safety mechanisms, of which one consists of a rotary locking screw and a nut jaw column. The thread pair clearance (TPC) of safety mechanisms is set at 60 mm. Owing to influential factors, the TPC changes randomly in the upward/downward-stroke of the ship chamber. If it diminished to 0, the safety mechanism would be jammed, thus resulting in disastrous accidents. By the bearing test of the drive system, 7 influential factors have been studied; 15 other influential factors (including 8 factors of manufacture and installation deviation, 3 factors of chamber offset, 2 factors of external load and 2 factors of wear) have been analyzed based on the design data. Results by the limit superposition reveal that the TPC change varies from −43.8 mm to +48.4 mm when the water level of the chamber ranges from 3.4 m to 3.6 m. According to the Gaussian distribution, the probability of the TPC change varied from −53.7 mm to +58.8 mm in the most detrimental status is 99.74%, therefore, the TPC remains in a safe condition. This paper puts forward that two-phase operation of the drive system should be adopted so as to reduce the maximum TPC change to −44.6 mm. [ABSTRACT FROM AUTHOR]

A nonlinear finite element model of the nut post reinforced concrete (RC) structure of the safety mechanism in the Three Gorges Project (TGP) ship lift was built by ANSYS software. Some irregular structures such as the nut post and the rotary rod were divided by curved surface into a series of regular parts, and the structures were all meshed to hexahedron. Constraint equations were defined between two interfaces with different element sizes and mesh patterns. PRETS179 elements were used to simulate the preload in the tendons and the pre-stressed screws, and the loss of pre-stressing force was calculated. Five extreme load cases were analyzed. The stress of each part in the structure was obtained. The results indicate that the maximum compressive stress of concrete C35 is 24.13 MPa, so the concrete may be partially crushed; the maximum tensile stress of the grouting motar is 6.73 MPa, so the grouting motar may partially fracture; the maximum von Mises stress of the rotary rod is 648.70 MPa, therefore the rotary rod may partially yield. [ABSTRACT FROM AUTHOR]