Global precipitation is becoming increasingly intense due to the extreme climate. Therefore, creating new technology to manage water resources is crucial. To create a sustainable urban and ecological environment, a water level and water quality control system implementing artificial intelligence is presented in this research. The proposed smart monitoring system consists of four sensors (two different liquid level sensors, a turbidity and pH sensor, and a water oxygen sensor), a control module (an MCU, a motor, a pump, and a drain), and a power and communication system (a solar panel, a battery, and a wireless communication module). The system focuses on low-cost Internet of Things (IoT) devices along with low power consumption and high precision. This proposal collects rainfall from the preceding 10 years in the application region as well as the region’s meteorological bureau’s weekly weather report and uses artificial intelligence to compute the appropriate water level. More importantly, the adoption of dynamic adjustment systems can reserve and modify water resources in the application region more efficiently. Compared to existing technologies, the measurement approach utilized in this study not only achieves cost savings exceeding 60% but also enhances water level measurement accuracy by over 15% through the successful implementation of water level calibration decisions utilizing multiple distinct sensors. Of greater significance, the dynamic adjustment systems proposed in this research offer the potential for conserving water resources by more than 15% in an effective manner. As a result, the adoption of this technology may efficiently reserve and distribute water resources for smart cities as well as reduce substantial losses caused by anomalous water resources, such as floods, droughts, and ecological concerns.

Scouring is one of the most common potential causes of bridge pile foundation failure with loss of life, economic and environmental impacts. Comprehensive studies on the numerical simulation of local scour around pile groups are still limited. This paper presents a numerical simulation using Flow-3D software to calculate the maximum sediment scour depth and investigate the mechanism around the groups of three cylinders in a tandem arrangement. A validation using the experimental study was carried out to confirm the reliability of the present numerical model. By using the Van Rijn transport rate equation and RNG k-ε turbulence model, the results of time evolution of scour depth and bed elevation contour show good agreement with the experimental study. The numerical simulation of three cylinders in a tandem arrangement were conducted with pile spacing ratios, G/D of 2 and 3. The local scour is affected by the horseshoe vortex from the downflow driven by the downward pressure gradient and rotates in front of the pile and the high bed shear stress, triggered by flow acceleration. The deepest maximum local scour depth is always obtained by the front pile as a shield pile, followed by the piles behind. The trend of the maximum local scour depth in a tandem arrangement is in accordance with the experimental studies and has a better agreement than previous numerical studies with the same model setup. This means that the numerical model used to simulate pile groups is accurate and capable of calculating the depth of sediment scour.

Scouring around the pile foundation is one of the potential failures of offshore bridges that must be assessed due to the possibility of damaging the bridge structure. However, there is still few in-depth research regarding local scour simulations around groups of six cylinders consisting of more than one row, which is most widely used for group arrangement performed numerically. The maximum scour depth and its mechanism surrounding the six-cylinder group were determined by numerical simulation of scour consisting of multiple rows arranged side-by-side and in tandem with different pile spacing ratios using Flow-3D software. A validation study using experimental investigation was completed to verify the accuracy of the computational model. Numerical simulations employing the Van Rijn transport rate Equation and the RNG k – ɛ turbulence model produced results for scour depth evolution and bed elevation contour, which were in accordance with the experimental study. The numerical results show that the best arrangement for the minimum scour depth of the six-cylinder group is the tandem arrangement of two rows and three columns with pile spacing ratio of 3.5. As a result of this study, engineers can optimize the design of bridge pile foundations to enhance safety and economic efficiency.

The article describes the effect of a magnetic field applied to a ferrofluid–lubricated hydrodynamic journal bearing–rotor system. A rotor with a single journal bearing in one end was built to be the test rig. The experimental results showed that 3 to 8 permanent magnets, arranged by different methods, can all increase the instability threshold of the oil bearing. Especially, the magnetic field formed by eight magnets has the optimal effect. The whirl speed and the whip speed can be increased from 3024 rpm to 4480 rpm, and from 3184 rpm to 5268 rpm.

This paper presents the simulation of 3D free surface flows by the two-phase least-squares finite element method (LSFEM). It is believed that this is the first time the LSFEM be extended from a 2D model to a 3D one and applied to investigate the 3D free surface flow phenomena. The dynamic and kinematic boundary conditions of free surface are described in an Eulerian coordinate system. The governing 3D Navier-Stokes equations in association with the color function are solved by the element-by-element scheme. In this simulation, the volume of fluid (VOF) method and continuous stress force (CSF) models are applied for the determination of the interface between the two phases of liquid and gas. The free surface position at each time step is determined by the distribution of the color function. The formation of the 3D model is carefully examined; and the quantitative comparisons of the 3D numerical simulations with experimental measurements and previous 2D numerical results are verified in good agreement. For the partial dam-break flows, it is shown that the two-phase LSFEM can effectively simulate the 3D flows. The unsteady water surface profiles of dam-break flow moving over an obstacle and the liquid drop are also simulated in this study. A 3D two-phase LSFEM has been established and carefully justified by some benchmark free surface flows. The method will be useful for the actual application to the two-phase flows with two immiscible fluids, such as liquid-gas flow, and metallurgic flow.

The infinite series solution to the boundary-value problems of Laplace’s equation with discontinuous Dirichlet boundary conditions was found by using the basic method of separation of variables. The merit of this paper is that the closed-form solution, or the singular similarity solution in the semi-infinite strip domain and the first-quadrant domain, can be generated from the basic infinite series solution in the rectangular domain. Moreover, based on the superposition principle, the infinite series solution in the rectangular domain can be related to the singular similarity solution in the semi-infinite strip domain. It is proven that the analytical source-type singular behavior in the infinite series solution near certain singular points in the rectangular domain can be revealed from the singular similarity solution in the semi-infinite strip domain. By extending the boundary of the rectangular domain, the infinite series solution to Laplace’s equation in the first-quadrant domain can be derived to obtain the analytical singular similarity solution in a direct and much easier way than by using the methods of Fourier transform, images, and conformal mapping.