Flap Gate Research Articles

Design and Optimization of Water Level Control Gate System in Malwathu Oya River, Sri Lanka

This research focuses on improving flood management of the Malwathu Oya River in Anuradhapura Historical City, Sri Lanka, by designing an efficient gate system for the weir of Halpan Ela in the Malwathu Oya River. Frequent flooding threatens agriculture, infrastructure, and public safety in this region. This research aims to enhance water level control in the upper reach of Halpan Ela Anicut by evaluating rainfall patterns, tank spillway efficiency, and gate operation challenges. Historical data on rainfall and tank spillage were analyzed. Flow simulations revealed significant pressure differences, with the existing gate structure showing an upstream pressure of 114,492.5 Pa at a maximum flow of 1740 m3/s, compared to 105,406 Pa for the new flap gate system at the same flow rate. This represents a pressure difference of 9 kPa, equivalent to a 0.9 m water head. Despite the system’s estimated cost of USD 0.1 million, the potential reduction in river flood damage, which currently exceeds USD 0.2 million annually, demonstrates its value. This research emphasizes the effectiveness of the flap gate system in reducing flood risks in Anuradhapura City compared to the existing gate type, though it is only a part of a broader flood mitigation strategy.

Phase classification and transient effects of the start-up process of multi-functional pump station in pump mode

In the context of achieving the goal of carbon neutrality, multi-functional pump stations (MFPS) have been greatly developed as a new energy system in recent years. The MFPS can operate in forward direction in pump mode to pump water and in turbine mode in reverse direction to generate electricity. At present, the instability of the MFPS during start-up process (SUP) in pump mode has become the key to restricting the operating life and further development of MFPS. In this paper, based on the motion characteristics of the pump and the cut-off facility (COF), the SUP of the MFPS in pump mode is clearly classified. In order to reveal the transient effect during the SUP, the steady-state full characteristic experiment (SFCE) of the pump was carried out. The occurrence phase of the transient effect during the SUP is analyzed, and the deviation between the steady-state external characteristics and the transient characteristics is revealed. In this study, the evaluation formula of the start-up completion degree (SUCD) of the MFPS in pump mode is proposed for the first time, and the evaluation and identification of the start-up progress at different phases are completed. The results show that the water flow in the system is in a reverse flow state in the Phase I. The SUCD of Phase I is 17 %. In the Phase II, The high-speed jet flow in the pump flows to the inlet of the guide vane (GV), which gradually changes the mainstream direction in the GV. A certain vortex structure can be observed at the exit of the flap gate (FG). The SUCD of Phase II is 61 %. In the Phase I and II, the dimensionless head of transient simulation is much larger than that of SFCE. In the Phase III, the flow state in the impeller will gradually stabilize. The transient effect disappears and the pressure fluctuation intensity decreases. The SUCD of Phase III is 93 %. In the Phase IV, the separation vortex that persists from Phase I-III at the tail of the GV blades disappears. The diversion capacity at the gate increases, and significant annular flow can be observed near the FG.

Numerical and field experimental study on the start-up process of a prototype axial-flow pump system considering the motion characteristics of cutoff facilities

Clarifying the evolutionary mechanism of the start-up process of a large axial-flow pump that includes cutoff facilities is of great significance for ensuring the safe and stable operation of such a system. However, the three-dimensional dynamic characteristics of the start-up process of a prototype axial-flow pump system (PAPS), considering cutoff facilities, are still unknown. In this paper, a method combining motor starting characteristic experiment, computational fluid dynamics, and field test of prototype pump system is proposed to study the starting process of PAPS. The results indicate that flow interruption facilities will significantly affect the start-up process of the pump system. High-speed forward fluid particles collide with reverse fluid particles in the guide vane channel during the acceleration of the pump owing to the influence of the cutoff facilities. A large number of wall vortex structures block the guide vane channel. This leads to a brief plateau period during the increase in instantaneous head. As the start-up process progresses, a clear horseshoe-shaped vortex structure is formed at the trailing edge of the guide vane, which subsequently falls back. The accelerated shedding of horseshoe-shaped vortical structures at the trailing edge of the guide vane induces high-frequency pulsating components, leading to a high-energy region of the pressure fluctuation signal at the outlet of the guide vane, which gradually expands toward higher frequencies. During this transition process, the flow field near the cutoff facility also exhibited significant unstable flow behavior. After the interaction between the outflow at the flap gate and the outflow at the gate, entrainment occurs, forming a region of circulating motion, and a large number of vortices with a jet-like structure are formed at the exit of the flap gate.

Flap Gate Weir Structural Design Using FEA

A flap gate weir commonly use to raise the level of a river or stream. It is a device that is used to regulate the flow of water in a river. It is typically located at the upstream of the river. Basically, flap gate weir is submerged under water, so hydrostatic force acting on submerged surfaces weir. The traditional design and analysis the resultant force acting on a submerged weir surface must specify magnitude of the force, direction of the force and line action of the force all is assumed on 2D which take long time calculation and might mistake. The aims of this paper is using finite element method design and study the flap gate weir structure instead of traditional analysis. In this paper the 3D model of flap gate weir was created by SolidWorks as assembly of flap gate weir which the flap gate weir was inclined 30 degrees and imported into Ansys Workbench for boundary conditions and calculations. The result from Ansys is used to find the specific hydraulic cylinder as the system needed. And modal analysis to check the vibration of the flap gate weir. By using finite element analysis the results study is satisfy by get results faster, know total deformation, know weak point and know where reinforce pad should put in and saving cost of materials when compare with traditional analysis.

Experimental and statistical analysis of the flap gate energy loss and pressure fluctuation spatiotemporal characteristics of a mixed-flow pump device

Experimental and statistical analysis of the flap gate energy loss and pressure fluctuation spatiotemporal characteristics of a mixed-flow pump device

Flexible and Slim Device Switching Air Blowing and Suction by a Single Airflow Control

This study proposes a soft robotic device with a slim and flexible body that switches between air blowing and suction with a single airflow control. Suction is achieved by jet flow entraining surrounding air, and blowing is achieved by blocking and reversing jet flow. The thin and flexible flap gate enables the switching. Air flow is blocked while the gate is closed and passes through while the gate is open. The opening and closing of the flap gate are controlled by the expansion of the inflatable chambers installed near the gate. The extent of expansion is determined by the upstream static pressure. Therefore, the gate can be controlled by the input airflow rate. The dimensions of the flap gate are introduced as a design parameter, and we show that the parameter contributes to the blowing and suction capacities. We also experimentally demonstrate that the proposed device is available for a variable friction system and an end effector for picking up a thin object covered with dust.

Brief Discussion on the Application of the New Melting-Deicing Device (MDD) on the Flap Gate of the Yitong River

In order to solve the winter operation problem of the flap gate of the Yitong River in Jilin Province, 4 sets of new Melting-Deicing Devices(MDD) were arranged in front of the flat gate, and the prototype observation research were carried out as well. The analysis results showed that MDD mixed compressed air into the water body during its work so that micro-nano bubbles were formed, and then the water body mixed with bubbles was pushed out and diffused horizontally under the drive of the motor, which had a high disturbance ability to the water body, and could realize the heat exchange between the bottom water body and the surface water body, thereby having an ice-thawing effect on the frozen layer, and effectively reducing the generation rate of ice nucleus in the water for the unfrozen water body, thus avoiding the generation of ice flowers and preventing the freezing of the water surface.

One-way flow system for improvement of the acid sulfate soil reclamation process in the Belanti II tidal swamp irrigation network, Central Kalimantan, Indonesia.

Belanti II tidal irrigation network was developed in 1980 on acid sulphate soil with an area of approximately 3976 ha. Belanti II has one primary channel and several secondary channels, without any water structures that regulate the direction of flow. Two-way flow occurs in the channel, supplying fresh water from the river at high tide and flowing back into the river at low tide. This two-way flow system inhibits the leaching process of acid sulphate soil. Up to now, acid sulfate soils are still found at a depth of 50-75 cm with a pH of 2.5 ~ 3.5. A one-way flow system is expected to improve water circulation, assisted by channel rehabilitation, collector channels and water control structures. The spillway structure at the secondary channel regulates the freshwater supply at high tide and the flap gate at the end regulates the flow of water to the collector channel at low tide. Hydraulic analysis was carried out using HEC-RAS modelling. The results showed the ability of the system to supply fresh water, flushing/leaching acid sulfate water and drainage the toxic water. The effectiveness of the system is evaluated regarding the direction and the volume of freshwater flowing into the secondary channel.

Field Investigation of Hydraulics and Fish Guidance Efficiency of a Horizontal Bar Rack-Bypass System

This paper investigates the hydraulics and fish guidance efficiency of a Horizontal Bar Rack-Bypass System (HBR-BS) installed at a hydropower plant with a design discharge of 33 m3/s. The HBR is placed at a horizontal rack angle of 38° to the flow direction with clear bar spacing of 20 mm. The BS has a vertical-axis flap gate with two openings. The HBR-BS complies with most literature design criteria. Velocity measurements were conducted using a moving-vessel Acoustic Doppler Current Profiler (ADCP). The fish monitoring study was conducted using a stow net, video, and ARIS sonar recordings. The fish monitoring calculations imply guidance efficiency of 84%, even for fish with total body lengths below 10 cm. Furthermore, the hydraulic results show that the flow field is favorable in terms of fish guidance due to a good alignment of the rack and the BS, corroborating the fish monitoring results. The results indicate that the HBR-BS functions not only as a physical barrier but also as a mechanical behavioral barrier for some small fish that are capable of physically passing the HBR. The present results are compared and discussed with the laboratory and field results from different studies in the literature.

THE INFLUENCE OF AUTOMATIC FLAP GATE ON EROSION IN TIDAL SWAMP AREA

This research aims to examine the problem of erosion and sedimentation in canals in swampy areas in South Sumatra, namely the P8-13S scheme of the canal (SPD) Telang I, Banyuasin regency with the influence of flap gate. The research method used is to perform simulations in the laboratory using a scale model and related parameters, such as velocity (v), depth of erosion (de), sedimentation (ds), water density (ρw), gravitation (g), time (t) and distance (x). Dimensional analysis to determine the related parameters that produce a dimensionless parameter relationship model is carried out using the Langhaar method. The result of the study was that the maximum relative erosion (de/t)max occurred at the canals estuary near the flap gate, which was 0.255 during simulation times of 5 minutes. While the maximum relative sedimentation (dd/t)max also occurred at the estuary of the secondary canals (SPD) of 0.05 for 5 minutes. So, the sediment transport process in the secondary canal (SPD) is generally influenced by flow velocity and the presence of a flap gate in the canal to regulate sediment transport.

The impact of creek formation and land drainage runoff on sediment cycling in estuarine systems

Field investigation and empirical analysis were used to assess the impact of tidal creeks and tidal flap gates (through which land surface runoff drains into estuaries) on sediment transport in the receiving waters downstream of the creeks and propose a semi-empirical model to assess the impact of water level rise and increased runoff flow, as may be expected under many climate change scenarios.Results show that there is increased suspended sediment concentration (SSC) at low tide within the deeper channel downstream of the tidal flap gate. This is due to the high SSC that is ejected by the creek because of land drainage runoff with SSC in the creek ranging from 47 mg/l to 300 mg/l at spring ebb tide and that in the deeper channel ranging from 22 mg/l to 104 mg/l. This effect was more pronounced at spring tides when the water level in the deeper channel was low. Substantial sediment is supplied by the creek on a spring low tide than a neap low tide due to higher exposure period of intertidal flats for spring low tides. The combination of creeks and tidal flap gates has the highest impact on SSC in the deeper channel at low tide and high surface runoff flow.It is recommended that moving forward on developments around coastal areas, management authorities create more effective and sustainable drainage systems with less impact on estuarine environments to protect aquatic life and promote habitat creation for a sustainable future. Such systems whereby there are numerous drainage flaps surrounding estuaries especially in intertidal flat areas should be transformed into systems with fewer secondary effects on estuarine environments.

How long the Mo.S.E. barriers will be effective in protecting all urban settlements within the Venice Lagoon? The wind setup constraint

The last IPCC report highlights that, along the present century, sea level rise driven by climate change will exacerbate the flooding frequency in coastal areas. Among others, the Venice Lagoon is one of the most vulnerable because of the presence of worldly famous historical urban settlements. To face this, a mobile flap gate system (Mo.S.E.) is nearly completed and has already raised across the lagoon inlets under testing phase to protect Venice from flooding. However, relative sea level rise and the wind setup effect during the closure of the lagoon, pose relevant management challenges such as timing and frequency to operate the barriers. In the present work, we first highlight some issues related to the management protocol currently adopted. We suggest a new strategy that optimizes the gate operation by identifying the shortest duration of closure that simultaneously prevents the flooding of all urban settlements within the lagoon. The new strategy is then used to estimate the Mo.S.E. management considering the last 20-year-long tidal record, but also for investigating different scenarios of relative sea level rise. The analysis we propose proves that the enhanced wind setup constraint will lead the Mo.S.E. system to fail in controlling all flood events starting from a relative sea level rise of +0.40 m. In addition, wind setup will increasingly often produce long and repeated closures, requiring further measures to combine flood protection, port and industrial activities and the conservation of the lagoon ecosystem.

Bearing capacity analysis of flap gate under impact load

In order to study the bearing capacity of flap gate under impact load, this paper uses the finite element calculation model to calculate the bending and shear resistance of the buttress of the flap gate under the design model, and designs the reinforcement amount of the section to study the bearing capacity of the flap gate under the impact load. The research result shows that the impact load controls the bearing capacity of the pier section, and the reduction of impact load can effectively alleviate the stress concentration at the corner of the pier. It is necessary to reconfigure the appropriate tension and compression reinforcement, but the stirrup and diagonal reinforcement do not need to be reconfigured.

EXPERIMENTAL STUDY OF DAM BREAK FLOW GENERATED BY THE FLAP GATE IN HORIZONTAL CHANNEL

The risk of dam break failure become one of the most important issues to decide the feasibility of reservoir and dam development in Indonesia. This paper presents an experimental work result of a dam break flow through a single oblique obstruction in a straight rectangular channel. The dam break flow was generated by a sudden swing of a flap gate set on the contraction join of a horizontal reservoir and a horizontal channel. The initial condition of the dam break flow is set up based on the water height in this reservoir. A spatial temporal measurement of depth and velocity of the generated dam-break flow was conducted around the obstruction. The flow depth was measured using an ultrasonic-based sensor supported by a GPRS communication system, and the flow velocity was measured using a high-speed type current meter. Less correlation between the measured depth and velocity flow in the first of three seconds after the flow generation, where the flow has a high intensity of turbulent, was observed due to the limitation of data acquisition capacity. Compared to Noel's experimental works where the dam-break mechanism is simulated using an uplift gate, the flow depth and velocity profiles of the current experimental work have a good agreement in its pattern and in less agreement in its magnitude. Meanwhile, compared to Noel's numerical model result, it has fewer agreement results. These differences might be occurred due to the influences of differences dam break mechanism and data acquisition system.

Decision Support System for Selecting Type of Moveable Dam Gate to Handle Tidal Flood Issued (A Case Study in The Parid River, Cilacap, Indonesia)

Cilacap is one of the regions in Indonesia in the southern coastal region bordering the Indonesian Ocean. In the coastal areas of Cilacap including Kawunganten district, there are frequent floods due to sea level rise. Tidal flood problem in Cilacap can be overcome by constructing a moveable dam. The selection of moveable dam gateis needed so that it can be work optimally. Data in this study were obtained through a questionnaire and distributed to respondents who were experts in the field of water. There are 5 criteria used to select the type of moveable dam gate, namely material, function, operational and maintenance, cost and location. There are 4 alternatives of moveable dam gatenamely flap gate, radial gate, sliding gate and rubber dam. The results of the questionnaire were then processed using Analytical Hierarchy Process. The results showed that the most important criteria to select the type of moveable dam gate is cost (0.273). The best alternative of moveable dam gate based on all criteria is flap gate (0.291). Movable dam with flap gate became the priority because it is easy to operate and low cost. The best location for moveable dam placement is before Ujungmanik Bridge with a score 0.376.

Experimental study and flow analysis on a new design of water-retaining sluice gate

Abstract As a water-retaining structure, the hydro-automatic flap gate (HFG) has advantages, such as easy operation, simple structure, attractive appearance, cheaper investment, and simple installation and maintenance compared to traditional gates. As such, the flow pattern analysis and flow rate analysis on this hydraulic structure have important engineering significance. In this paper, an experimental study was carried out for testing the water flow during the opening process of a bottom shaft driving flap gate. Three different opening velocities (once in 20 years, once in 50 years, once in 100 years) were selected for obtaining detailed characteristics. Then the space-time change laws of velocity and other hydraulic parameters of gate, gate pier and stilling pool were described. Moreover, the results of the flow regimes under conditions of once in 20 years, once in 50 years, once in 100 years were compared with each other. The findings and conclusions of this paper provide the basis for the project implementation in a sediment-laden river, and provide reference for other similar projects.

Theoretical and Experimental Analysis of Operating Conditions of a Circular Flap Gate for an Automatic Upstream Water Level Control

This article introduces a flow controller for an upstream water head designed for pipe culverts used in drainage ditches or wells. The regulator is applicable to water flow rates in the range of Qmin < Q < Qmax and the water depth H0, exceeding which causes the gate to open. Qmin flow denotes the minimum flow rate that allows water to accumulate upstream of the controller. Above the maximum flow rate Qmax, the gate remains in the open position. In the present study, the position of the regulator’s gate axis was related to the water depth H0 in front of the device. Derived dependencies were verified in hydraulic experiments. The results confirmed the regulator’s usefulness for controlling the water level.

A Method for Judgement of Operation States of Auto Flap Gate

A Method for Judgement of Operation States of Auto Flap Gate

Study on the practical replacement strategies of the existing steel flap gate

Study on the practical replacement strategies of the existing steel flap gate

Semi-circular flap gate as a flow metering structure in circular channels

This research proposes slit and solid semi-circular flap gates for discharge measurement along the circular channels under free flow condition. A top-hinged flap gate deflects by flowing water against its weight due to the flow hydrodynamic forces. The deflection angle of the semi-circular flap gate can be considered as either independent variable or dependent variable. Two models are proposed for the stage-discharge relation based on the Buckingham's theorem of dimensional analysis. The first model considers the deflection angle as an independent variable while the second model considers it as a dependent variable. A series of laboratory experiments (254 runs) were performed to investigate the flow process of slit and solid semi-circular flap gates located along of two horizontal, circular pipes. Using the data collected from two pipes of nominal diameters 20 and 30 cm, the proposed models were calibrated. The first model has an average error less than 2.5%, while the second general model has an average error about 2.55%, thus actual discharge through the circular channels can be accurately estimated using the proposed stage-discharge equations. The results showed that viscosity effects are significant in second model, while these effects are important in first model only for slit flap gates. The proposed inline flap gate offers a simple and reliable discharge measurement approach with acceptable accuracy.