126 publications from this institution
Some countries grapple with data scarcity for calibration purposes when establishing current hydrodynamic models, which often require many parameters. In this context, this research presents a practical simulation methodology for hydrodynamic modelling suitable for application in bay and estuarine systems based on mass and momentum equations and requiring only one parameter for calibration—bed friction. The proposed simulation methodology is applied to a linear open channel measuring 200,000 m long. A sensitivity analysis of the bed friction is conducted to assess the proposed methodology’s response to the maximum water levels achieved. The results are compared to linear theory, indicating that the proposed simulation methodology effectively represents the water phase. In all simulations, the maximum root mean square error is less than 2.1% when neglecting bed friction and 4.69% when a bed friction of 0.005 is considered. The proposed simulation methodology can be a practical tool for hydrodynamic modelling in shallow waters.
Entrapped air pockets in water pipelines play a significant role in influencing transient over-pressures during filling procedures. Several research is focused on highlighting the attenuation of pressure peaks in pipes with single air pockets. This research studies the air-water interaction during rapid water filling processes in an irregular pipeline and air pockets in different branches, and how the trapped air can attenuate the over-pressure peaks. A three-dimensional computational fluid dynamics (CFD) model was developed, and numerical results of the model were validated through experimental measurements. For a given initial air pocket condition upstream of the high point, the maximum air pocket over-pressure was 11% to 32% lower when the descending pipe segment initially contains air compared to when it contains water. In sum, it was found that entrapped air pockets at high points of water pipelines can help mitigate transient over-pressures considering specific initial hydraulic conditions prior to filling operations.
Air pockets can become trapped at high points in pipelines with irregular profiles, particularly during service interruptions. The resulting issues, primarily caused by peak pressures generated during pipeline filling, are a well-documented topic in the literature. However, it is surprising that this subject has not received comprehensive attention. Using a model developed by the authors, this paper identifies the key parameters that define the phenomenon, presenting equations in a dimensionless format. The main advantage of this study lies in the ability to easily compute pressure surges without the need to solve a complex system of differential and algebraic equations. Numerous cases of filling operations were analysed to obtain dimensionless charts that can be used by water utilities to compute pressure surges during filling operations. Additionally, it provides charts that facilitate the rapid and reasonably accurate estimation of peak pressures. Depending on their transient characteristics, pressure peaks are either slow or fast, with separate charts provided for each type. A practical application involving a water pipeline with an irregular profile demonstrates the model’s effectiveness, showing strong agreement between calculated and chart-predicted (proposed methodology) values. This research provides water utilities with the ability to select the appropriate pipe’s resistance class required for water distribution systems by calculating the pressure peak value that may occur during filling procedures.
