Hydraulic Calculation Research Articles

Groundwater Hydraulics in Increased Spring Discharge following Earthquakes: Some Applications and Considerations

Earthquakes often entail alterations in the groundwater flow regime, in the phreatic level, surges and losses of springs, and the discharge in brooks. A variety of theoretical approaches attempt to elucidate the post-earthquake effects on spring discharge. This study adopts a conceptual approach, primarily presenting diverse methods to estimate water released by earthquakes involving calculations of discharge surpluses in springs. This study delves into refined techniques rooted in groundwater hydraulics, displaying applications of analytical and simulation methodologies to quantify earthquake-induced groundwater discharge in springs. This research investigates springs as natural indicators and applies mathematical precipitation–runoff models, particularly the CREC model, to simulate hydrographs in post-earthquake scenarios. We apply analytical procedures or mathematical simulation techniques employed in groundwater hydraulics for natural aquifer recharge calculations. Firstly, we briefly describe the methods based on the analysis of depletion curves of hydrographs in spring discharge. Additionally, specific mathematical rainfall–runoff models used to simulate hydrographs of karstic springs, along with derived analytical approximations, are adapted for this scenario. These hydraulic calculations involve the depletion coefficient and hydrodynamic volumes of aquifers, parameters that reveal certain aspects of the relation between groundwater and earthquakes. Three main features are: (a) Acknowledging faults as the primary geological structures in transmitting pore pressures due to earthquakes. Thus, for large and deep faults, which connect the ground surface with the Earth’s crust bottom—where earthquakes trigger—the depletion coefficient, α, usually reaches high values (α = 0.1 days−1). Therefore, these faults become more sensitive to pore pressure than other lithologies. (b) Elucidating the mechanisms of permeability enhancement caused by earthquakes. (c) Highlighting the substantial volumes in motion within the Earth’s interior, which, for instance, could constitute a significant source for the origin of mineral deposits. Mathematical calculations enable the determination of the volume of mobilized water that can be discharged by gravity in each earthquake. This, along with its recurrence, justifies the substantial mineralization volumes.

Multiphase friction calculation peculiarities based on models implemented in the "d-Flow" software package

In order to ensure efficient and safe operation of oil and gas fields, a tool is required to design production wells and surface infrastructure. It is important to take into account the physical processes that occur during production, as well as fluid properties and phase transitions. The "d-Flow" software package enables the creation of a comprehensive field model based on geological and field data to calculate hydraulic losses of pipelines and forecast hydrocarbon production. The fluid flow modelling is based on the calculation of multiphase friction with the wall of a well or a pipeline. The article discusses the implementation of four friction models: the Beggs-Brill model, the Gray model and its modification, and the Mukherjee-Brill model. The purpose of this work is to compare the predictions of friction models with the results obtained using commercial realizations of the same models. The results of the Schlumberger PIPESIM hydraulic simulator calculations were used as a benchmark for comparison with the "d-Flow" models. Numerical experiments were conducted to investigate two-phase flow under varying well geometry and flow regimes. The models used were compared, and the results showed that the predicted liquid holdup had an average relative error of 0.06%. In some cases, the error was as low as 0.02%. The predicted cumulative pressure drop in the well did not exceed 0.34% for all considered models. Based on the comparison results, we conclude that the "d-Flow" software package is suitable for calculating pressure drop in wells of different geometry and surface networks.

Analysis of dependences for hydraulic calculation of pipes made of polymer materials

Assess the influence of the equivalent roughness coefficient and roughness parameters on the value of the calculated pressure losses in pipelines made of polymer materials. Consider normalized calculation dependencies for the hydraulic calculation of pressure pipes made of polymer materials. Assess the difference in the pipeline hydraulic characteristics constructed using various formulas. Give recommendations on the choice of calculation dependence for determining the coefficient of hydraulic resistance, determining the specific pressure loss along the length for pipelines made of polymer materials. The dependence of the calculated specific pressure loss along the length on the equivalent roughness coefficient has been constructed. Hydraulic calculations were carried out using various calculation dependencies to determine the coefficient of hydraulic resistance of a pipeline with a diameter of 400 mm, made of PVCO 500, on a 1 km long section. The hydraulic characteristics of the pipeline are obtained and comparative results of calculating the values of specific pressure losses along the length when calculated using different calculation dependencies are presented. The magnitude of the change in pressure loss along the length is determined depending on the change in the value of the equivalent roughness coefficient. A calculation formula is recommended for determining the coefficient of hydraulic resistance for pipes made of polymer materials, taking into account the values of the height and step roughness parameters. Key words: polymer pipeline, pressure pipeline, roughness parameters, hydraulic calculation, pressure losses.

INCREASING THE LEVEL OF ENVIRONMENTAL SAFETY OF PUMPING UNITS BY ENERGY SAVING DURING REGULATION

The relevance of improving calculation methods for pumping units of hydraulic systems in order to save energy and correspondingly increase their level of environmental safety is substantiated. To speed up hydraulic calculations and increase their accuracy, it is proposed to approximate the existing characteristics of centrifugal pumps, which are usually presented in the equipment passport in graphic form, with a quadratic parabola. The general equations for the analytical determination of the working point parameters, the construction of the pressure characteristics of the pump at a new rotation frequency and the formula for the geometric location of the tops of the pressure characteristics for different rotation frequencies of the impeller were obtained. It has been proven that with frequency control, the pump characteristic shifts equidistantly along the parabola of proportionality. In a similar way, the characteristics of the pump are affected by the casing of the impeller. An equation has been obtained that allows, without resorting to the grapho-analytical method, to calculate the change in the characteristics of the pump with a proportional change in all its dimensions and a constant frequency of rotation and the equation of the curve of similar modes. This curve is proposed to be called the similarity curve. It is shown that the velocity coefficient is a constant value along the polynomial curve. On the basis of the obtained results, a method of comparative analysis of the energy efficiency of the regulation of the pumping unit by changing the rotation frequency and proportionally changing all dimensions of the impeller is proposed. The application of the method is demonstrated on concrete examples. Achieving the highest efficiency of the pumping unit ensures the lowest energy consumption, thus minimizing emissions of harmful substances into the atmosphere. Keywords: environmental safety, efficiency, centrifugal pumps, flow regulation, hydraulic resistances, change of rotation frequency, laws of similarity, laws of proportionality

Результаты гидравлических расчетов каналов Черноземельской обводнительно-оросительной системы

Purpose: hydraulic calculations of the current water supply network of the Chernozemelskaya irrigation system channels. Materials and methods. The materials for the calculations were: operational records of the Chernozemelskaya irrigation system, the results of field surveys of channels and data from instrumental measurements of water levels, velocities and water discharges in the surveyed discharge section lines of distributary channels. The field work was carried out according to the generally accepted rules and methods of surveys, hydrometric measurements and assessment of the reclamation facilities state. Channel hydraulic calculations were performed for the conditions of constant water flow in their channels on rectilinear sections. Calculations of the main elements of the water cross-section of the Chernozemelskaya irrigation system channels were carried out using passport data and the results of field surveys of these channels. Results. Calculations of the main elements of the water cross-section of the channels for the control stations on the Yashkul and Gashun distribution canals of the Chernozemelskaya irrigation system were performed, rating curves of discharge and average water flow velocity in channels from the depth of their filling were constructed; permissible (non-eroding and non-silting) velocities of water flow in the channels were determined. Conclusions. It was found for the discharge section line on the Gashun distribution canal, that siltation of the channel will occur at a water flow discharge of Q < 2.75 m³/s and channel filling of h < 1.0 m. When assessing the channel of the Gashun canal for the susceptibility to erosion, it was determined that the channel in the control station section can pass the specified discharge without being eroded. Checking the channel of the Yashkul distribution canal in the control section for siltation and erosion showed that its channel will not be eroded in the considered range of water flow velocities from 0.62–1.14 m/s.

Determination of Pipe Diameter Using Optimization Method

During the design phase of engineering networks, a critical issue remains the selection of pipe diameters that minimize capital investments for transporting the heat carrier from the heat source to the consumers. Object of study: a pressurized pipeline of circular cross-section with a moving heat carrier. Subject of study: total monetary costs for transporting the heat carrier as a function of the chosen pipeline diameter. Objective of study: to determine the pipe diameter that achieves maximum cost savings for transporting the heat carrier under given design conditions. Research methods: theory of hydraulic calculation for circular cross-section pipelines and theory of heat transfer through a single-layer cylindrical wall under steady-state conditions. Research results: using an example from a centralized heating system pipeline section, it was established that for a mass flow rate of the heat carrier equal to 32.9 t/h, the optimal pipe size would be 76×3 mm (nominal diameter 70 mm). Under current tariffs for thermal energy (24.82 USD/Gcal) and electrical energy (6.65 USD/(MW⋅h)), the total monetary costs for transporting the heat carrier over a heating season would be 56.28 USD per 1 running meter of pipeline. In comparison, with a nominal diameter of 50 mm, the total costs amounted to 90.37 USD; with a diameter of 80 mm, the costs were 63.29 USD. The developed method for hydraulic design calculations is universal and can be applied in the design of engineering networks where the working medium is a moving heat carrier (steam or hot water).

Experimental Investigation of Liquid Pressure in a Straight Circular Cross-Section Pipeline

An evaluation of the reliability of a widely accepted method for determining pipeline hydraulic resistance is conducted, based on a comparative analysis of theoretical data with the results of laboratory investigations. The research object is a liquid flowing under pressure in a straight pipeline with a circular cross-section. The subject of the study is the pressure losses of the liquid along the length of the pipeline. The aim of the research is to verify the existing method for determining the hydraulic resistance of a straight pipeline. Research methods include the Darcy-Weisbach law for determining pressure losses due to friction in the pipeline and experimentation. The research findings indicate that the air pressure at the inlet and outlet of the pipeline, as determined by experimentation/calculation, were as follows: for a flow capacity of n = 0.33 (1/3) – 4.48 Pa and 2.11 Pa / 4.87 Pa and 1.70 Pa; for n = 0.66 (2/3) – 9.11 Pa and 3.45 Pa / 9.35 Pa and 3.41 Pa; for n = 1 – 15.4 Pa and 5.10 Pa / 15.7 Pa and 5.92 Pa. The absolute and relative errors of indirect technical measurements of linear pressure losses due to friction in the pipeline were approximately ≈1.04 Pa and ≈10.6 %, respectively. Conclusions drawn from the study indicate that the root mean square deviations of calculated air pressure values along the pipeline from experimental data, with a sample volume N = 9, were as follows: for a flow capacity of n = 0.33 (1/3) – σ = 0.40 Pa; for n = 0.67 (2/3) – σ = 0.36 Pa; for n = 1 – σ = 0.61 Pa. Based on the assessment of the error of indirect technical measurements of pressure losses in the pipeline and deviations of calculated air pressure values from instrumental measurement results, it can be concluded that the existing method of hydraulic pipeline calculation is adequate.

Balanced operation strategies of district heating systems based on dynamic hydraulic-thermal modeling

As the improvement of district heating systems, the fine-tuning of operational equipment has become a promising direction. However, in the practical district heating systems, relying solely on manual control and the existing basic models, the dynamic hydraulic-thermal process is hard to cover. Consequently, the primary side control in the current district heating system mainly results in the over or under-supply of heating substations. This article constructs a dynamic hydraulic-thermal model and performs a balanced operation strategies optimization based on the hydraulic-thermal model. The linearization and iterative optimization process are adopted to simplify the hydraulic and thermal modeling for the single pipe, and the hydraulic and thermal calculation are conducted sequentially. For the primary side network in the various operation conditions, the dynamic hydraulic-thermal model is established. The heating supply imbalance of the primary side return temperatures among different heating substations is defined and optimized based on the dynamic hydraulic-thermal model and the particle swarm optimization algorithm. In the case analysis, the results of heating supply imbalance before and after optimization are 0.81 K and 0.47 K, respectively, with a 42.0 % reduction in heating imbalances after optimization. The proposed method could contribute to the fine-tuning of heating substations and the reduction of energy waste due to the imbalanced heating supply, which is significant for the operation strategies of district heating systems.

Условно динамический анализ работы центробежного компрессора в агрегатную линию рециркуляции

The procedure for conditionally dynamic (quasi-dynamic) hydraulic and thermal calculation of recirculation lines of compressor stations has been developed. As an example, the solution to the problem of reconstruction of the linear compressor station of the main gas pipeline is considered. Using the developed methodology, options for upgrading the existing recirculation line in order to increase its throughput are proposed. The gas temperature change in the recirculation line is analyzed due to various factors (heat exchange with soil, throttling) at the starting modes of constant and variable rotations of the compressor rotor. The analysis of the change in the recirculation cycle time and the rate of temperature growth at the compressor inlet per unit time is performed.

Конструктивные решения и гидрометрические параметры трактов рыбоходно-нерестовых каналов с элементами усиленной шероховатости

Purpose: to develop proposals for the design and methodology for calculating the hydrometric parameters of fish passage and spawning channel tracts at waterworks. Materials and methods. The factual basis of the work is data of hydrometric studies of the Nikolaevsky and Konstantinovsky fish passage and spawning channels and materials of technical justification of channel projects at the Bagaevsky and Kochetovsky waterworks on the river Don. The methodological basis of study was the results of the authors’ research and well-known recommendations for determining the parameters of channel tracts with enhanced roughness. Results. The hydrometric parameters of fish passage and spawning channels are accepted and calculated assuming the provision of necessary conditions for attracting anadromous fish into the channels, their passage from the downstream of the waterworks to the upstreams and the spawning of some of them in the tracts. The following parameters were considered: flow rate, average flow velocity, bottom depth and width, cross-sectional shape and slope ratio, underwater gradient and channel length, types and sizes of gravel-pebble channel coating and elements of enhanced roughness. As a result of the study, the recommendations for flow rates, flow velocities and depths, the choice of the cross-section of the channel, the type and size of fractions of the gravel-pebble mixture were proposed. A methodology for hydraulic calculation of the fish passage and spawning channel tracts has been developed for the accepted conditions of its operation taking into account the arrangement of the channel with enhanced roughness elements. To test the methodology, the hydrometric parameters of the conditional fish passage and spawning channel tract, equipped with enhanced roughness elements, with an average flow velocity of 0.9 m/s was calculated. Conclusion. Recommendations for calculating the hydrometric parameters of fish passage and spawning channel tracts with enhanced roughness elements and a methodology for such calculations that meet the requirements of fish farming and biological justification on formation of conditions for fish migration and spawning in their tracts are proposed.

Development of innovative equipment for milk microflora inactivation

The article is dedicated to the development of innovative equipment for the inactivation of milk microflora. It provides an analysis of existing methods to suppress the growth and destruction of microorganisms in milk, aiming to enhance product quality indicators. The advantages and disadvantages of current pasteurization equipment are highlighted. An overview of alternative methods for milk inactivation is presented, focusing on the impact of ultraviolet radiation on bacteria and lower organisms. It is concluded that a major advantage of ultraviolet (UV) milk treatment, in addition to its bactericidal effect, is its minimal impact on proteins under efficient operating conditions. Considering the limited penetration of UV rays into milk, a device is proposed—a milk disinfection separator that separates microorganisms from the main product by placing them in the form of a thin laminar film accessible for effective irradiation. Special attention is given to justifying the parameters of the UV irradiation section. The methodology for hydraulic calculation of device movement is presented, along with a method for determining the bactericidal effectiveness of UV irradiation on microorganisms and the necessary lethal dose for this purpose. By specifying the system's productivity, knowing the bactericidal dose required to deactivate bacteria, and considering the irradiation intensity of the UV source, the dimensions of the irradiation section and the required electrical power of the equipment are determined. The article proposes modern LED arrays with the necessary UV wavelength range, along with diagrams for their connection and equipment control.

Analysis of the influence of the heat of combustion of gas on the determination of gas pipeline diameters

Natural gas plays a significant role in the energy supply structure. The country’s primary energy supply includes 29 million tons of natural gas, which accounts for 30.2 % of the country's total energy balance. Part of the biomass, combustion and output increased from 2.3 % to 11.5 %. On the other hand, the majority of gas distribution systems were put into operation thirty to fifty years ago and met the regulatory requirements in force at the time. Now, gas flows and loads in these networks have changed, and the standard service life has expired. The state of gas networks has been significantly affected by military operations. The requirements of regulatory documents in the field of gas supply have been significantly expanded in order to harmonise with the current European legislation. Calculations were introduced based on the volume of natural gas in energy units, which is determined by the higher calorific value. There are some conflicts in the national normative base, which causes the problems for gas supply design. It is proposed to use the higher heating value of gas when determining the diameter of gas networks. The use of the higher calorific value of 38.3 MJ/m3 in the hydraulic calculation of gas pipelines will allow for a more rational selection of diameters in the sections. The use of gas consumption in energy units will reduce the actual diameters of gas pipelines, their material consumption, and thus the overall cost of the system. The influence of the gas component composition on its physical and chemical properties and, as a result, on the system capacity is considered. In addition, as a result of the implementation of thermal modernisation measures in buildings, the amount of gas consumed is reduced and there is a need to optimise the values of the coefficients of simultaneous operation of gas. For today, old values are used, which are defined in 1987, when the norms of gas supply and living conditions were different. Thus, the coefficients should be adapted to the modern life and norms

ИНСТРУМЕНТЫ ЦИФРОВИЗАЦИИ В ПРАКТИКЕ ПРОЕКТИРОВАНИЯ ПРИ РЕКОНСТРУКЦИИ ПОДЗЕМНЫХ ТРУБОПРОВОДОВ БЕСТРАНШЕЙНЫМИ МЕТОДАМИ

The article focuses on the possibilities of multi-optional design of repair and rehabilitation works on dilapidated pressure pipeline networks with the use of automated complexes in order to achieve minimum energy costs in water transportation with regard to the temperature factor. Two automated programs based on hydraulic and energy calculation operations are presented as digital tools. As a basic variant of reconstruction of dilapidated pipelines, the trenchless Swagelining technology was accepted. It is realized by pulling pre-compressed polymer pipes into old pipelines with their subsequent straightening. The paper presents information on regulatory and technical documentation and the application of advanced technology, installation and operation conditions, as well as comparative assessment of energy consumption after reconstruction of dilapidated sections of pipelines with polymer pipes with the possibility of minimizing energy consumption during water transportation under non-isothermal conditions of pipeline operation.

Calculation of Proper Time of Concentration for Drainage Design in Construction Projects for Urban Development

The design and construction of a proper drainage system are important for any urban development project, small or big. Hydrological and hydraulic calculations are used to design the drainage systems. The calculation of peak flow is one of the common hydrological methods applied to determine the drain sizes for all construction projects. Peak flows and hydrographs can be calculated using several techniques. In order to calculate the peak flow, the design rainfall duration has to be appropriate, which will reflect the critical storm duration. The critical storm duration, on the other hand, depends on the time of concentration (tc) of the catchment. However, most of the equations for tc available in the literature are empirical. At least 23 equations could be traced in various references, which consist of different geophysical and other hydrological parameters. This paper is intended to explain the importance of the proper use of tc to calculate peak runoff flow for construction projects, as accurately as possible. A review of the existing methods used to calculate the time of concentration revealed inconsistencies among a few methods found in the literature. The correct value of the time of concentration (tc) is important for the application of the Rational Method, as the value of tc helps the designer assume the storm duration critical to get the maximum peak flow value. If the critical storm duration is not used in the Rational Method, the drain will be undersized, and the overflow of the storm runoff may happen. Therefore, ample attention should be given to the calculation of the time of concentration to ensure the safety, economy, and sustainability of the drainage system in any development project.

Determination of the particularities of the hydraulic friction factor variation of collecting drainage pipelines

The object of the study in this paper is collecting perforated drainage pipelines, in particular, the determination of the hydraulic friction factor λdr, which significantly affects the parameters of the investigated pipes. Clarifying this issue will solve an important engineering problem – to develop a reliable method for hydraulic calculation of collecting perforated drainage pipes. As the main drawback of most of the available theoretical and experimental works on this topic is the insufficient consideration of the filtration characteristics of the surrounding soil and the material of the pipeline walls. Experimental studies of pressure drainage pipes with different design characteristics made it possible to find out the real picture of fluid flow in the pipe. Based on the research results, experimental dependences of λdr on the ratio of the fluid inflow velocity to the average flow velocity in the corresponding section (Uh/V), as well as on the design characteristics of the channel were obtained. The maximum possible flow that can be collected and passed by a collecting drainage pipeline with the specified design and filtration characteristics is determined. It is shown that a larger value of the specified ratio corresponds to larger values of λdr. This result can be explained by the effect of the attached flow on the main flow. Obviously, some energy is spent on the interaction of the attached and the main flow in the pipe, which leads to additional head losses. In the paper, dependencies were obtained for calculating the studied factor for collecting drainage pipelines. Using them in the calculation of drainage pipes will increase the reliability and efficiency of land reclamation systems, in which these pipelines are important structural elements

Методика и алгоритм расчета местных потерь напора в трубопроводах

The article is devoted to the hydraulic calculation of pipelines. For the storage of liquid products used in the national economy, there are tanks, which are usually combined into tank farms. Equipment for transporting liquids within the tank farm includes pumping units, pipelines, shut-off and control devices, etc. The growing needs of the economy create the necessity of build new and expand existing storage facilities for liquid products at industrial and transport objects. Hydraulic calculation is an important part of the tank farms pipeline systems design. This paper presents a methodology and algorithm for determining of local fluid pressure losses in pipelines. The calculation is based on the characteristics of pipeline system sections in which local hydraulic resistance occurs: a change in the diameter or direction of the pipeline, installation locations of auxiliary devices, etc. The Weisbach formula is used to calculate the local pressure losses. This takes into account the values of the local resistances coefficients and average flow velocities in the respective sections. The average flow velocities are determined by the given values of the flow rates and flow profiles on the sections. The local losses coefficients, depending on the type of resistance, are also found according to the calculation formulas, or are set as the initial values. Local pressure losses are calculated for curved sections of pipelines, conical transitions (confusers and diffusers), inlet and outlet sections, shut-off, control and safety valves, instrumentation, branches.

A Novel Deformation Analytical Solution and Constitutive Model for Fractured Rock Masses

In order to study the deformation and stability of a fractured rock mass, existing research suggests that fracture deformation, which is usually obtained by evaluating the equivalent deformation modulus, dominates the deformation of a fractured rock mass. However, this parameter is difficult to obtain in theory and practice, which limits the application of rock mass deformation analysis methods. In order to calculate the deformation of fractured rock masses, the mass of the rock is regarded as a sponge-like material, and it is assumed that the deformation of a water-saturated fractured rock mass under external force load is approximately equal to the net flow of fracture water. Based on this assumption, firstly, the relationship between rock mass deformation and fracture flow is studied through a single-fracture rock mass model. The hydraulic properties of the fracture are characterized by the permeability coefficient, and the fracture deformation in the rock mass is equivalent to the fracture flow. The fracture deformation calculation formula is derived from the fracture hydraulics calculation formula, and this is compared with the measured data. The rationality of the calculation formula was verified. On this basis, the calculation formula for rock mass deformation, including multiple groups of fracture surfaces, is proposed, and the stress-strain constitutive relationship of a complex rock mass is established. The correctness of the calculation method was verified by comparing it with other theoretical calculation results.

Numerical Study on the Automatic Ballast Control of a Floating Dock

Abstract The ballast control of a floating dock mainly relies on manual operations, which can be time-consuming and requires skilled workers. This study proposes an automatic ballast control system for floating docks, which improves operational efficiency and safety during the vessel docking process. A numerical model is developed to simulate the dynamic process of the floating dock's operations, which includes a six degrees-of-freedom (6DOF) model, a hydrostatic force model, a hydrodynamic force model, and a hydraulic model. The hydrostatic force model is developed using the Archimedes law and a strip theory along the longitudinal direction. The hydrodynamic model is made based on the effects of added mass and dynamic damping. The hydraulic model is proposed to deal with the hydraulic calculation of the ballast water system. The present automatic ballast control is designed based on a modified proportional controller (P-controller) to control the valve opening angles when the pitch or roll angles are larger than the corresponding threshold values. Without using controllers, the roll angles of the dock can reach 8.9 deg and 13 deg during the ballasting and de-ballasting operations, respectively. The present modified P-controller with optimized control parameters can stabilize the dock during the de-ballasting operation and keep the maximum pitch and roll angles no larger than 0.016 deg and 0.0783 deg, respectively. During the ballasting operation with the same control parameters, the roll and pitch are below 0.0604 deg and 0.0145 deg, respectively. The present automatic control will be further implemented in the vessel docking cases and can significantly improve the stability of the dock.

Requirements for hydraulic modeling of wartime water supply networks and for CBRN pollution risk management

Military actions on the territory of Ukraine demonstrated that the termination of centralized water supply can occur both as a result of the direct destruction of water supply facilities, and as a result of power outages, deterioration of water quality at the source, inaccessibility of the water source itself, etc. Therefore, the situation requires the application of completely new approaches to hydraulic modeling, the establishment of new requirements for modeling modes and analysis of the obtained models. Today, the geo-information systems implemented at many Ukrainian water utilities should be used to model adverse scenarios, conduct hydraulic calculations for them, and then determine the optimal ways to improve the situation. There was also a need to conduct hydraulic calculations when developing a response program to chemical, biological, radiation, nuclear (CBRN) water pollution. The analysis of the situation presented in the article allows us to draw a conclusion about the expediency of using Epanet software for this purpose, since specialized software complexes usually do not have the necessary functions. Moreover, for systems that do not have an appropriate hydraulic model, the first stage should be its development, which will include the digitization of the original cartographic information, on-site refinement of distribution networks, determination of network loads, calibration of the model at control points.

Numerical study on the de-ballasting operation of a floating dock with a malfunctioning pump

In normal de-ballasting operations of floating docks, each ballast pump manages a specific group of ballast tanks, independently of the others. However, if one pump is malfunctioning, a connection valve between the group and its adjacent group is opened, allowing its adjacent pump to control two groups of tanks simultaneously. This study aims to investigate the de-ballasting dynamic process in the event of a ballast pump malfunction by utilizing a numerical model of a full-scale digital floating dock. In the present numerical model, the dock is represented as a rigid body with six degrees of freedom and is subjected to hydrostatic, hydrodynamic, and mooring forces. To maintain pitch and roll angles within predefined limits, a modified P-controller is employed to regulate the valve opening angles at all the ballast tanks. Hydraulic calculations for the ballast water system with a malfunctioning pump are conducted, and the numerical results demonstrate the effectiveness of the present modified P-controller when dealing with a malfunctioning Pump No. 1.