Lake thermal dynamics have been considerably impacted by climate change, with potential adverse effects on aquatic ecosystems. To better understand the potential impacts of future climate change on lake thermal dynamics and related processes, the use of mathematical models is essential. In this study, we provide a comprehensive review of lake water temperature modeling. We begin by discussing the physical concepts that regulate thermal dynamics in lakes, which serve as a primer for the description of process‐based models. We then provide an overview of different sources of observational water temperature data, including in situ monitoring and satellite Earth observations, used in the field of lake water temperature modeling. We classify and review the various lake water temperature models available, and then discuss model performance, including commonly used performance metrics and optimization methods. Finally, we analyze emerging modeling approaches, including forecasting, digital twins, combining process‐based modeling with deep learning, evaluating structural model differences through ensemble modeling, adapted water management, and coupling of climate and lake models. This review is aimed at a diverse group of professionals working in the fields of limnology and hydrology, including ecologists, biologists, physicists, engineers, and remote sensing researchers from the private and public sectors who are interested in understanding lake water temperature modeling and its potential applications.

This paper presents the results of an experimental study on the mean and turbulence structures of flow in a vertical slot fishway with slopes of 5.06 and 10.52%. Two flow patterns existed in the fishway and for each one, two flow regions were formed in the pools: a jet flow region and a recirculating flow region. The mean kinetic energy decays rapidly in the jet region and the dissipation rate in most of the areas in the pool is less than 200 W∕ m3 . For the jet flow, the nondimensional mean velocity profile across the jet agrees very well with that of a plane turbulent jet in the central part of the jet with some scatter near its boundaries. Its maximum velocity decays faster compared to a plane turbulent jet in a large stagnant ambient. The jet presents different turbulence structure for the two flow patterns and for each pattern, the turbulence characteristics appear different between the left and right halves of the jet. However, the turbulence characteristics show some similarity for each case. The n...

A physical model study was conducted to examine the development of submerged sand erosion through a slot on a defective sewer pipe. Various parameters that affect the erosion process were studied, including particle size, defect size, position on the pipe, and water depth. This experimental study used particle image velocimetry analysis to provide a deeper understanding of the mechanism of sand erosion due to defective sewer pipes. The sand velocities were determined, and the sand and water flow rates were measured. After the erosion process was initiated, the sand and water outflow rates quickly reached the steady state until the eroded zone reached the slot opening. During the steady erosion process, the region of sand motion was restricted to a narrow zone above the opening, with sand particles sliding into the newly formed cavity at the angle of repose. An increase in slot width significantly increased the sand and water flow rates. A decrease in sand particle size from medium to fine resulted in a decreased sand flow rate mainly due to decreased water flow. An increase in sand particle size from medium to coarse resulted in a decreased sand flow rate due to the arching resistance close to the slot for larger sand particles. In this study, the sand flow ceased when the ratio between the slot width and particle size was less than 3.1. The ratio between the sand and water flow rates was found to be a function of the ratio of slot width to particle size. The water level above the pipe and the slot position affected the sand and water flow rates. A simple analytical model was developed to estimate the sand and water flow rates in the erosion process.

Acoustic doppler velocimeter (ADV) data can be contaminated by spikes from various sources. Available despiking methods were found to encounter difficulties in despiking ADV data from a turbulent jet flow. An iteration-free despiking algorithm was developed for highly contaminated ADV data by applying a bivariate kernel density function and its gradient to separate the data cluster from the spike clusters. It is shown that the new method overcomes some of the deficiencies of the existing despiking methods.

A physical model study was conducted to investigate the mechanisms of air entrainment in a tall plunging dropshaft of 7.7 m in height. The water flow in the dropshaft was observed to break up into small drops of approximately a few millimeters diameter at a drop height of 5 m. The dominant water drops were found to be approximately 2 mm and they fell at an average speed of approximately 6 m/s. An analytical model was developed to predict the amount of air drag and air flow needed on the basis of the momentum transfer from the water drops. The drag force induced a vertical air pressure gradient, and the model prediction compared well with the measurements. The entrained air flow rate increased with the water flow rate, but the ratio of the air to water flow rate decreased from approximately 20 to 5 times when the water flow rate increased from 3.9 to 47.7 L/s. The air pressure was negative at the top of the dropshaft to allow the ambient air to be entrained, and it increased to the atmospheric pr...

Air injection systems have a wide range of environmental engineering applications. In this study, we conducted experiments on air injection in a relatively large water tank to investigate the effect of nozzle type, including single/multiple orifice nozzles and a porous airstone, on the characteristics of the bubbles and the induced flow structure. Measurements of bubble characteristics and flow field surrounding the bubble core were obtained using a double-tip optical probe and particle image velocimetry, respectively. The results revealed that bubble velocity did not change significantly with different nozzles, but bubble size decreased significantly while interfacial area, liquid entrainment rate, and kinetic energy of the mean and turbulent flow increased significantly by using the porous airstone instead of nozzles with large orifices. The results for a nozzle with multiple orifices of small diameter are comparable to those for the airstone, which suggests the suitability of its use for systems suscep...