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1. Siphon Break Phenomena Associated With Pipe Leakage Location

   https://doi.org/10.1115/1.4054654  

   Zanje, Sumit R.; Bian, Linlong; Verma, Vivek; Yin, Zeda; Leon, Arturo S. (November 2022, Journal of Fluids Engineering)

   Abstract This work investigates the siphon break phenomenon associated with pipe leakage location. The present study is divided into two parts: (1) an unsteady three-dimensional (3D) computational fluid dynamics (CFD) model is developed to simulate the pressure head (water level) and discharge in the simulated siphon using the volume-of-fluid (VOF) technique under no-leakage condition and (2) using the model developed in the first part we investigated the siphon break phenomenon associated with pipe leakage location. The calculated results of transient water level and discharge rate at the simulated siphon for the no-leakage condition were in good agreement with the experimental measurements. In addition, the velocity, pressure fields, and phase fractions in the siphon pipe were analyzed in depth. The methodology and findings presented show that leakage above the hydraulic grade line and close to the top inverted U section of the siphon pipe ultimately leads to the siphon breakage, which is not the case for a leakage below the hydraulic grade line. It is also concluded that if leakage is above the hydraulic grade line and the leakage position is far away from the upper horizontal section of the siphon pipe, it may not lead to the immediate siphon breakage as ingested air gets removed with siphoning water, allowing it further time to cause complete siphon breakage. 

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2. Open capillary siphons

   https://doi.org/10.1017/jfm.2021.1056  

   Wang, Kaizhe; Sanaei, Pejman; Zhang, Jun; Ristroph, Leif (February 2022, Journal of Fluid Mechanics)

   Flow in the inverted U-shaped tube of a conventional siphon can be established and maintained only if the tube is filled and closed, so that air does not enter. We report on siphons that operate entirely open to the atmosphere by exploiting surface tension effects. Such capillary siphoning is demonstrated by paper tissue that bridges two containers and conveys water from the upper to the lower. We introduce a more controlled system consisting of grooves in a wetting solid, formed here by pressing together hook-shaped metallic rods. The dependence of flux on siphon geometry is systematically measured, revealing behaviour different from the conventional siphon. The flux saturates when the height difference between the two container's free surfaces is large; it also has a strong dependence on the climbing height from the source container's free surface to the apex. A one-dimensional theoretical model is developed, taking into account the capillary pressure due to surface tension, pressure loss due to viscous friction, and driving by gravity. Numerical solutions are in good agreement with experiments, and the model suggests hydraulic interpretations for the observed flux dependence on geometrical parameters. The operating principle and characteristics of capillary siphoning revealed here can inform biological phenomena and engineering applications related to directional fluid transport. 

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3. Impact of Pipe Leakage Location on Siphon Flow Breakage

   https://doi.org/10.1061/9780784484258.112  

   Zanje, S. R.; Verma, V.; Yin, Z.; Leon, A. S. (January 2022, 2022 ASCE-EWRI World Environmental & Water Resource Congress)

   Siphons are often used for releasing water by gravity, especially from shallow ponds. This paper investigates the hydrodynamic characteristics of the flow in a siphon under leakage (e.g., pipe puncture) and no-leakage conditions using the OpenFOAM Computational Fluid Dynamics (CFD) package. The volume-of-fluid (VOF) method was used to solve the air-water two-phase flow, and the standard k-ε model was used to model the turbulence. The CFD model was assessed using experimental measurements for the no-leakage condition. The simulations for the leakage condition focused on investigating the siphon flow break phenomenon as a function of leakage location. The results show the impact of leak position on the siphon flow break and the suitability of OpenFOAM for simulating the complex two-phase flow dynamics that occurs in a siphon. 

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4. Accelerated Degradation Testing of Rigid Wet Cooling Media to Analyse the Impact of Calcium Scaling

   https://doi.org/10.1115/IMECE2018-88508  

   Dakshinamurthy, Hemanth N.; Siddarth, Ashwin; Guhe, Abhishek; Kasukurthy, Rajesh; Hoverson, James; Agonafer, Dereje (November 2018, Proceedings of the ASME 2018 International Mechanical Engineering Congress and Exposition)

   Rigid wet cooling media is a key component of direct and indirect evaporative cooling systems. Evaporation is the process of a substance in a liquid state changing to a gaseous state. When water evaporates only water molecules get evaporated and the other chemicals in the water are left behind on the surface as residue. Many studies have been conducted on how the change in air flow velocity, media depth, porosity and water distribution affect performance of the cooling system. The operational efficiency of the cooling media varies over its life cycle and depends primarily on temperature and speed of inlet air, water distribution system, type of pad and dimension of the pad.Although evaporative cooling when implemented with air-side economization enables efficiency gains, a trade-off between the system maintenance and its operational efficiency exists. In this study, the primary objective is to determine how calcium scale affects the overall performance of the cooling pad and the water system. Areas of the pad that are not wetted effectively allow air to pass through without being cooled and the edges between wetted and dry surface establish sites for scale formation. An Accelerated Degradation Testing (ADT) by rapid wetting and drying on the media pads at elevated levels of calcium is designed and conducted on the cellulose wet cooling media pad. This research focuses on monitoring the degradation that occurs over its usage and establish a key maintenance parameter for water used in media pad.As a novel study, preliminary tests were mandatory because there were no established standards for media pad degradation testing. Sump water conductivity is identified as the key maintenance parameter for monitoring sump replenishing and draining cycles which will result in reduced water usage. The average water conductivity in the sump during wetting cycles increases monotonically when ADT was performed on a new media pad. An empirical relationship between sump water conductivity and number of wetting cycles is proposed. This information will be very helpful for the manufacturers to guide their customers for maintenance of the media pad and sump water drain cycles. 

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5. Quantitative Vibration-Based Prognostics of Railcar Bearings Using Encoder-Decoder LSTM

   Cantu, E; Rodriguez, A; Hernandez, A; Martinez, S; Tarawneh, C; Ai, L; Yang, J (June 2026, 2026 ASME Quantitative Nondestructive Evaluation)

   Forecasting railcar bearing health with artificial intelligence can significantly enhance railway maintenance by enabling a shift from reactive interventions to proactive strategies. Although hundreds of controlled freight rail bearing experiments have been conducted using onboard accelerometers and extensive data have been collected, a persistent gap remains between laboratory data and the reliable prediction of bearing condition in field service settings. In this paper, a one-shot forecasting method is introduced based on an encoder-decoder long short-term memory (LSTM) architecture to predict bearing health from Root-Mean-Square (RMS) vibration trends and to anticipate the onset of defects before observable failure. The proposed model is designed to effectively learn long-term temporal dependencies and nonlinear degradation dynamics while leveraging information across multiple experimental datasets to improve generalization. The performance of the model is evaluated based on independent test experiments, where predicted RMS sequences are compared against the measured ground truth. The results demonstrate accurate and stable forecasts across varying operating conditions and degradation patterns without requiring additional sensing modalities. The proposed framework can provide a robust, practical, and nondestructive approach for data-driven prognostic maintenance in the railway domain, supporting earlier maintenance decisions, improved safety, reduced downtime, and enhanced operational reliability. 

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