Ljubomir Budinski

The Knićanin–Čenta subcatchment area, located in Central Banat, is a fertile agricultural region whose water regime is significantly influenced by the water levels of the surrounding rivers—the Danube, Tisa, Begej, as well as the Karaš canal. During May and June 2019, while the TurkStream gas pipeline was under construction, the area experienced heavy rainfall, resulting in flooding of approximately 35% of the total surface area of the Knićanin–Čenta system. The aim of this study was to determine whether, and to what extent, the construction of the gas pipeline—primarily the formation of barriers and the placement of pipes in the canals—affected the occurrence or extent of flood-related damage. For this purpose, a hydraulic model was developed using the EPA SWMM software package.

Comprehensive hydraulic modelling of a large urban water supply system, based on GIS data, with actual spatial distribution of water demand achieved through georeferenced water metre data. Establishing a model for simulating a large urban water distribution system poses challenges from multiple perspectives. This paper presents an approach to modelling a complex network, demonstrated on the case of the regional distribution system of the city of Novi Sad. In the analysed study, an accurate model was developed using a comprehensive dataset encompassing all system components. A realistic spatial redistribution of demand within the network was achieved by including the complete set of water meters. This approach yielded straightforward calibration and high agreement between simulated and observed pressure and discharge values. The selected software package, EPANET-GISpipe, proved suitable for addressing such issues. The research has shown that a detailed analysis based on water meter readings enables reliable simulation of large-scale water distribution systems with complex operational dynamics.

This article presents an encoding for the quantum Lattice Boltzmann method algorithm using Carleman linearization. In contrast to previous articles [C. Sanavio et al., AVS Quantum Sci. 6, 023802 (2024)10.1116/5.0195549; Phys. Fluids 37, 037123 (2025)1070-663110.1063/5.0254588], the encoding used allows for local collision rules while keeping a higher probability to obtain the correct result, which is of the order of 10^{-2}. The algorithm scales as O[log_{2}^{2}(N)+Q^{3}] at each time step with N the number of lattice sites of the two-dimensional lattice and Q the number of channels with a constant number of qubits when using dynamical circuits.

The primary goal of this paper is to develop a mathematical model that describes groundwater flow within a porous medium. By employing mathematical modelling techniques for fluid flow analysis, valuable insights can be gained into complex flow conditions that are often difficult to assess using conventional analytical methods. Given that the spatial and temporal variations of parameters relevant to the system can be expressed through specific mathematical formulations (typically in the form of complex partial differential equations) it is advisable to apply appropriate numerical methods, as they provide a strong strategy for effectively addressing the challenges associated with the system. One of the challenges encountered in groundwater research is the lowering of groundwater levels (GWL) during the construction of buildings. Before the construction begins, it is required to lower the GWL in the foundation pit to ensure dry working conditions. The most requested data for this purpose are groundwater flow and GWL. This paper focuses on lowering the GWL for a specific object while ensuring that the stability of surrounding buildings remains unaffected. To achieve this objective, it is crucial to design and implement a drainage system with adequate capacity, considering the characteristics of the aquifer. Additionally, it is important to assess filtration stability, particularly to prevent suffusion, by carefully selecting an appropriate protective filter course. The analysis of groundwater flow at the specified location was conducted using a 3D model to simulate the flow regime within a porous medium. Both conceptual and numerical groundwater modeling were performed using the GMS 10.7 software. Based on the adopted filtration coefficient from the geotechnical study, several solutions were developed. In each case, it was necessary to ensure that the GWL was lowered to the required elevation and to prevent suffusion by controlling the maximum velocities at the entrance of the filter structure.

Lattice-gas algorithms (LGA) are a class of algorithms including, in chronological order, binary lattice-gas cellular automata, integer lattice-gas algorithms (ILGA), and lattice Boltzmann method (LBM). They are largely used for simulating nonlinear systems. Starting from one-dimensional ILGA, we design an algorithm where we carry out a fraction of the possible collisions. These fractions are then adapted to reproduce LBM equilibrium distributions, resulting in an adaptive lattice-gas algorithm that achieves the same simulation results of LBM. Considering this, we develop a quantum algorithm that involves a linear collision operator capable of simulating the same phenomena, while still using a measurement and reinitialization procedure. Multi-time-step implementation is possible in some specific cases, briefly discussed.

Building upon the Integer Lattice Gas Automata framework of Blommel and Wagner [Phys. Rev. E 97, 023310 (2018)2470-004510.1103/PhysRevE.97.023310], we introduce a simplified, fluctuation-free variant. This approach relies on floating-point numbers and closely mirrors the Lattice Boltzmann Method (LBM), with the key distinction being a different collision operator. This operator, derived from the ensemble average of transition probabilities, generates nonlinear terms. We propose this float lattice gas automata collision as a computationally efficient alternative to traditional and quantum LBM implementations.

We explore the use of classical programming techniques in implementing the quantum lattice Boltzmann method in the Intel Quantum SDK—a software tool for quantum circuit creation and execution on Intel quantum hardware. As hardware access is limited, we use the state vector simulator provided by the SDK. The novelty of this work lies in leveraging classical techniques for the implementation of quantum algorithms. We emphasize the refinement of algorithm implementation and devise strategies to enhance quantum circuits for better control over problem variables. To this end, we adopt classical principles such as modularization, which allows for systematic and controlled execution of complex algorithms. Furthermore, we discuss how the same implementation could be expanded from state vector simulations to execution on quantum hardware with minor adjustments in these configurations.

This study investigated the interaction of groundwater flow and foundation piles located in the vicinity of the Danube River. The piles represent an obstacle to the groundwater flow, causing a backwater effect upstream whilst increasing the local flow velocity. On the other hand, a high flow velocity around the piles can cause suffusion of the surrounding soil in the long term, thus significantly reducing the shaft resistance of the piles. A 3D model of groundwater flow and its impact on the piles was developed in the software 10.3 package GMS based on MODFLOW 2005. The model was calibrated by comparing the calculated results with the measured values in the control well for different values of the filtration coefficients. In the calibration process, foundation piles were not applied in the model. After the calibration process, the piles were implemented into the model and the underground flow was simulated in the study area for the calibrated year 2006. The impact analysis was carried out by comparing the groundwater level change over time in the pile zone at three control points, in cases with and without the piles, along with the flow net analysis at the piles’ location. The results indicate no influence of the piles on the groundwater flow in the study area, both in terms of critical flow velocities and a possible backwater effect upstream.

The study investigates an interaction of groundwater flow and foundation piles located in the vicinity of the Danube River. The piles represent an obstacle to the groundwater flow, causing the backwater effect upstream, whilst increasing the local flow velocity. On the other hand, high flow velocity around the piles can cause the suffusion of the surrounding soil in the long term, thus significantly reducing the shaft resistance of the piles. A 3D model of groundwater flow and its impact on the piles was developed in the software package GMS.9.2 based on MODFLOW 2005. It was calibrated by comparing the water level values obtained as a result of the simulations with varying filtration coefficient inputs with the observed values in the monitoring well. After the calibration process, piles were implemented into the model and the underground flow was simulated at the study area location for the calibrated year 2006. The impact analysis was carried out by comparing the groundwater level change over time in the pile zone in three control points, in cases with and without the piles, along with the flow net analysis at the location of the piles themselves. The obtained results indicate an absence of the influence of piles on the groundwater flow at the study area location, both in terms of critical flow velocities and in terms of a possible backwater effect upstream.

A new algorithm for solving the Navier-Stokes equations (NSE) on a quantum device is presented. For the fluid flow equations the stream function-vorticity formulation is adopted, while the lattice Boltzmann method (LBM) is utilized for solving the corresponding system of equations numerically for one time step. Following the nature of the lattice Boltzmann method, the proposed quantum algorithm consists of five major sections: initialization, collision, propagation, boundary condition implementation, and calculation of macroscopic quantities. The collision and boundary condition step is quantumly implemented by applying the standard-form encoding approach, while the quantum walk procedure is applied for the propagation step. The algorithm is implemented by using IBM's quantum computing software development framework Qiskit, while for the verification purposes two-dimensional (2D) cavity flow is simulated and compared with classical code.