Analysis of the load characteristics of a local corner region inside a liquid tank impacting water surface obliquely

Right-angle dihedral structures produce strong, highly correlated returns that dominate radar cross-section (RCS) and image signatures. Conventional absorbers or random coding metasurfaces often lose effectiveness across wide frequency bands and angles, and cannot adequately suppress the corner-induced hot spots. We propose a wideband super-dispersion encoded surface (SDES) conformally applied to dihedral facets. The approach co-designs input-admittance for absorption with a deterministic super-dispersion phase sequence to redistribute energy spectrally and angularly, thereby decorrelating the returns. We implement SDES on a thin composite panel and evaluate it on canonical dihedral and dihedral–cylindrical hybrid configurations. Unlike diffuse or random coding schemes, SDES enforces broadband, angle-stable dispersion with a deterministic sequence that specifically addresses corner singularity scattering. We also introduce perceptual-hashing as an imaging-domain metric to link RCS control with observable radar-image changes. From 12–18 GHz, SDES reduces the average monostatic RCS by 9.6 dB on a right-angle dihedral. In dihedral–cylindrical hybrids, SDES removes the corner hot spots and drives the radar-image similarity index down to 0.31, confirming substantial alteration of scattering signatures.

The cross-flow effect in the compressor corner region alters the separation-induced transition flow of the suction surface boundary layer. As the Reynolds number (Re) decreases, the mechanism of three-dimensional boundary layer separation-induced transition flow coupled with crossflow becomes more complex, making the analysis of loss formation mechanisms more difficult, thereby heightening the challenge of efficient flow control. This study investigates a high-subsonic compressor cascade to elucidate the fundamental mechanisms by which Re effects induce variations in separation-induced transition characteristics across different blade heights, with particular emphasis on the coupling mechanism between crossflow and streamwise instability. The results demonstrate that crossflow induces spanwise non-uniformity in the separation, transition and reattachment positions of the three-dimensional suction surface boundary layer. Elevated viscosity, identified as the primary factor delaying shear layer transition at low Re, retards the growth of maximum streamwise velocity differential near the separated shear layer. This attenuation reduces the growth rate of Kelvin–Helmholtz (K–H) instability, ultimately postponing transition. Concurrently, low-Re effect enhances the sensitivity of three-dimensional boundary layer separation-induced transition characteristics to crossflow disturbances. The axial transition position under crossflow interaction exhibits a progressive advancement from end wall to midspan followed by subsequent retardation. Within regions devoid of secondary separation, a linear correlation exists between transition location and the position of maximum spanwise velocity in separation bubbles. In contrast, transition positions show strong dependence on reverse crossflow extent in secondary separation regions. Finally, the maximum separation bubble thickness within the separation-induced transition regime determines the turbulent viscous dissipation occurring in the separated shear layer, and suppressing the crossflow should be considered to reduce the profile loss, which provides a new perspective for the efficient loss control for compressors at low Re.

Surface water quantity and quality is important for arid and semi-arid regions where many people, including underserved and Indigenous communities, rely on a scarce resource for drinking water, irrigation, livestock, and ceremonial uses. The southwestern United States, and specifically the Four Corners Region (Colorado, Arizona, New Mexico, Utah), is an example of this situation. Elevated concentrations of metals including aluminum, arsenic, and lead were identified in previous studies and this study in the San Juan River from below the Navajo Dam, through the Navajo Nation to Mexican Hat, Utah. An interdisciplinary team applied approaches and principles of geology, geochemistry, geomorphology, hydrology, and statistics to gain a better understanding of the tributaries supplying the source(s) of metals to the San Juan River. This paper provides an overview of the thematic issue titled Metal geochemical fingerprinting to identify sub-watershed source contributions to surface water at a regional arid watershed scale, Four Corners Region, USA. An overview of sampling sites, techniques, and potential sources of metals is provided. Approaches used in this study could be applied to investigations in similar systems globally.

Additive manufacturing has become an important production method nowadays and thanks to the developments in this field, it makes it possible to manufacture complex parts with new practical properties. Although additive manufacturing methods make it possible to produce parts with complex geometries, parts produced with additive manufacturing usually have surfaces with a high degree of roughness. Because of the negative effects on the part's fatigue life and stress concentration caused by this rough surface, it limits its usage in industrial applications. To enhance their surface quality, these parts require post-processing. However, this post-processing enhancement cannot be performed with conventional methods due to the complex geometry of the parts produced with additive manufacturing methods. That is why, the abrasive flow machining (AFM) process which, is an option with better results in the surface finishing of AM parts, is used to improve the surface characteristics. On the other hand, in the abrasive flow machining (AFM) process, the effectiveness of material removal tends to decrease in corner regions, particularly when the flow channel geometry involves sharp-edged profiles such as square or hexagonal shapes. In the study, Poly Lactic Acid (PLA) parts produced with Fused Deposition Modeling (FDM) technique in square, hexagonal and cylindrical sections created in the same volume were produced and subjected to AFM process and surface improvements on the corners and edges were observed. This study aims to demonstrate, through both analytical and experimental approaches, that the efficiency of the AFM process is reduced at the corners of such geometries while overall surface quality is improved. Furthermore, solution-oriented recommendations are proposed based on the analytical evaluations to enhance process performance in these critical regions.

Abstract The loss generation in the corner region of compressors is highly dependent on vortex dynamics. When the Reynolds number (Re) decreases to a critical value, the flow unsteadiness induced by multiscale vortex structures changes significantly, resulting in difficulties in loss quantification and control. In this study, a high-subsonic compressor cascade was taken as the research object, and the low-Re-effects on the flow unsteadiness and loss generation in the corner region were clarified. A new source of flow unsteadiness in the corner region, namely,, low-frequency oscillation (LFO), which is induced by the resonance among multiple vortex structures with different frequencies, is first identified. When Re decreases from 5.6 × 105 to 2.5 × 105, more energy is transferred to LFO through the resonance process. As such, the region of LFO is distinctly extended, which becomes the most important source of flow unsteadiness in the corner region at a low Re. Furthermore, the contributions of various flow unsteadiness on the generation of TKE are quantified via multiscale proper orthogonal decomposition (mPOD) analysis, with the results showing that LFO contributes the largest proportion to TKE at a low Re. Thus, the loss increases or performance deterioration caused by the low-Re-effect is attributed mainly to the enhancement of LFO. That is to, say, the top priority of loss reduction in the corner region at a low Re is to suppress LFO growth by weakening the multiscale vortex-induced resonance process.

Abstract A real-case supercell tornado simulation is analyzed to understand the rapid vertical acceleration of near-surface air parcels leading to intense vertical vorticity stretching and vortex intensification. The vertical acceleration is primarily due to effective buoyancy force and dynamic vertical perturbation pressure gradient force (VPPGF), and the latter is further decomposed into the splat and spin components by solving diagnostic pressure equations. Positive dynamic VPPGF is the dominant forcing responsible for near-ground vertical acceleration, while effective buoyancy is much smaller near ground. In the initial stage of tornado intensification, upward dynamic VPPGF is dominated by the spin term associated with the vorticity of the lowering tornado cyclone embedded within a mesocyclone, because maximum vertical vorticity and associated perturbation pressure minimum are located off the ground. As the tornado further intensifies, the maximum vertical vorticity and corresponding perturbation pressure minimum shift to the ground level, the spin-induced VPPGF becomes negative or downward. At this stage, the upward splat-induced VPPGF is found to be responsible for promoting and supporting continued upward vertical acceleration and vorticity stretching near the ground. The splat component is largest near the ground and close to the corner region of the tornado because of the strong flow deformation there. Trajectory analyses of parcels entering the tornado further substantiate that the dominant term in the upward dynamic VPPGF transitions from the spin term before the maximum vertical vorticity lowers to the ground, to the splat term after the lowering. As the air parcels rise, buoyancy becomes the primary force for continued updraft acceleration, aided by latent heating after reaching saturation.

Natural and anthropogenic sources of lead (Pb) can adverselyimpactwater and sediment quality within large watersheds and the ecosystemsthey support. This study examined the sources and distribution ofPb within the San Juan watershed located in southwestern Coloradoand the Four Corners region of Colorado, New Mexico, Arizona, andUtah (western United States). Samples for this project were collectedfrom 2018 to 2021 and included seeps and springs located within themineralized headwaters region, surface water, and sediments alongan approximately 570 km stretch of riverbed. Concentrations and isotopiccompositions of Pb showed that (1) source attribution using all stablePb isotope ratios, 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb, allowedfor an analysis of metal dilution and changing sources of Pb; (2)in upstream reaches, Pb from landscape disturbance related to miningoperations and weathering of mineralized geologic units representedthe most significant Pb source, accounting for as much as 90% of thePb within the upper Animas River sediments; and (3) Pb attributedto the mining-impacted headwaters decreased downstream through theAnimas River and San Juan River and represented up to about 50% ofthe Pb in downstream sediments. The proportion and mass of Pb derivedfrom the mining district were reduced in downstream areas due to increasedsediment delivery to the central river channels from tributaries andweathering of Paleozoic- to Tertiary-aged sedimentary deposits. Ouranalysis demonstrates that Pb isotope ratios can be used to effectivelytrace Pb transport through watershed systems where multiple Pb sourcesexist and where Pb concentrations may be similar to geogenic values.The study results indicate that the spatial and temporal variationof Pb isotopic signatures is associated with multiple contributionsfrom natural sources, which are influenced by seasonality and hydrologicalfactors.

Compressed Air Energy Storage (CAES) in abandoned coal mines offers a cost-effective and sustainable solution for large-scale energy storage. This study presents a comprehensive analytical framework to evaluate the thermo-mechanical behavior and long-term structural stability of three-layer underground chambers with circular and horseshoe-shaped cross-sections. Based on the theory of complex elasticity and conformal mapping, analytical solutions for stress and displacement are derived under steady-state thermal conditions. The framework incorporates both mechanical loads-such as in-situ stress and internal gas pressure-and temperature-induced thermal stresses, which are often overlooked in traditional models. Using the Cao Zhuang Coal Mine in Shandong Province as a case study, the analytical results are validated against finite element simulations performed in COMSOL 6.2. The validation demonstrates strong agreement in both temperature and stress distributions across different burial depths. Comparative results reveal that while circular chambers maintain relatively uniform stress profiles, horseshoe-shaped chambers are prone to localized stress concentrations, especially near the lower arch and corner regions. This makes them more vulnerable to structural failure under thermal cycling conditions. The findings underscore the importance of incorporating thermal effects in underground energy storage system design. The developed methodology offers a computationally efficient alternative to fully numerical simulations, enabling rapid scenario assessment and structural optimization. This work provides theoretical and practical insights into the safe reuse of abandoned mine tunnels for energy storage, contributing to the long-term feasibility of compressed air energy storage systems and the advancement of clean energy infrastructure.

Diffusers are essential for flow deceleration and pressure recovery, but the adverse pressure gradient often induces boundary layer separation that degrades performance. This study employs large eddy simulation (LES) to investigate how inflow velocity influences the internal flow structures of a square-section diffuser with emphasis on separation phenomena. Three inflow velocities—5, 10.5, and 30 m/s—are considered, and the flow characteristics are analyzed in terms of time-averaged, instantaneous, and fluctuating behavior. Results show that increasing inflow velocity significantly enhances static pressure recovery and exponentially reduces total pressure loss, improving diffuser efficiency. Two types of separation are identified: (1) a centerline bubble near the diverging section entrance and (2) large-scale three-dimensional corner separations. The centerline bubble triggers shear layer instability and separation-induced transition, leading to the formation of hairpin vortices. In contrast, corner regions experience earlier instability accompanied by vortex leg crossover due to vortex interactions from adjacent walls. With higher inflow velocity, vortices become smaller and more coherent, and corner separation zones shrink, reducing interference with centerline vortices. Corner separation also weakens in the mid-to-downstream regions. Turbulent kinetic energy and Reynolds stresses increase, but relative kinetic energy decreases, suggesting enhanced main flow stability despite increased asymmetry and localized instabilities. This study provides high-fidelity insights into the mechanisms of flow separation and vortex formation in square-section diffusers. These findings contribute to the development of turbulence models and the optimization of diffuser performance.

Physical and chemical characteristics of sediment influence the transport of metals in rivers. The San Juan River and its tributaries are located in the Four Corners Region in the southwestern United States and the watershed contains a wide variety of potential metal sources. Comparisons of past and present sediment data provide insight on the effects of seasonality and storm events to sediment transport within a watershed. Comparisons suggest finer (<0.63 µm) sediment particles increase at a greater rate during intense storm events than coarser sediment particles. These fine, clay-sized sediments have a greater potential for metal sorption. Statistical analyses compared upper and lower portions of the San Juan River. Results show total elemental concentration decreases in sediments (1,785.15 μ g/L) and that concentrations increase in the aqueous phase (2,063.08 μ g/L) downstream in the San Juan River. Geochemical and scanning electron microscopy with energy dispersive spectroscopy analyses suggest that sediment clay particles are the most likely constituent transporting metals in the San Juan River. Metal transport is further aided by metal oxide coatings developing on the surfaces of larger particles. Increases in aggregation of fine-grained particles in the downstream portions of the San Juan River is also likely to bind elements within sediments which can act as both a source and sink for metals in the lower watershed.

The aim of this study was to examine the alterations in the dynamic properties of damaged aluminum plates following repair with carbon fiber composite patches. Initially, cracks of varying lengths (10, 20, 30, 40, and 50 mm) were introduced at different locations (mid-straight, mid-diagonal, corner-straight, and corner-diagonal) on 1.8 × 200 × 200 mm aluminum plates. Subsequently, these induced defects were repaired using single-sided and double-sided patches produced via the vacuum infusion method. The research then focused on analyzing how the resonance frequencies, vibration mode shapes, and damping ratios of the plates changed after these repairs. The dynamic properties of the plates were determined using the Experimental Modal Analysis (EMA) method. The results indicate significant changes in the dynamic properties of the plates due to crack formation and patch repairs. The first five modes of the plates were analyzed, and variations in resonance frequencies, influenced by crack length, location (middle or corner regions), and application type (single-sided or double-sided), reached up to 6.07%. While no substantial change was observed in the vibration mode shapes, particularly at lower frequencies, the fifth vibration mode showed the highest variation at 8.8%. Additionally, remarkably high changes in vibration damping ratios, up to 37.39%, were observed. The findings were presented in a comparative and elucidative manner, aiming to contribute to the literature.

In arid to semi-arid landscapes, sporadic monsoonal events, varying widely in scale and distribution, can generate overland flow resulting in streamflow in ephemeral channels. These channels may contain metal-laden sediments that are a by-product of the weathering and erosion of local geologic units. To evaluate the potential for local geology to contribute aluminum, arsenic, and lead to the San Juan River, northwestern New Mexico, U.S., the distributions of geologic units were delineated for 12 hydrologic basins within the greater San Juan River watershed. Concentrations of aluminum, arsenic, and lead in the predominant geologic units were compiled from data in the National Geochemical Database. Chemical weathering indices (CIW) were calculated for geologic units with greater than 5% coverage in the entire San Juan River watershed. Based on CIWs of the major geologic units, the Mesaverde Group (CIW= 95.2), Chinle and Dolores Formations ( combined ) (CIW=93.3), and Mancos Shale ( combined ) (CIW=82.6) are the most likely units to weather, erode, and contribute sediments with elevated concentrations of aluminum, arsenic, and lead to the San Juan River. The results of this study show the importance of understanding geologic sources of sediments because they could be substantial contributors of constituents of concern to water, especially in arid environments where surface water may be the only source of water in the region.

Weathered uranium (U) rich sediment and mining and production activity could contribute to elevated concentrations of U in surface waters. In the San Juan River watershed in the Four Corners region of the United States, U-rich deposits are common in many geologic formations and, historically, U mining in the region was prevalent. The goal of this work was to identify potential sources of U to the San Juan River from ephemeral and perennial tributaries during monsoonal storms. Data show that most of the tributaries in the watershed have elevated U concentrations in surface-water samples, greater than the U.S. Environmental Protection Agency maximum contaminant level of 30 micrograms per liter (µg/L) for U. Although parts of the watershed have been mined for U, not all elevated concentrations were found in regions that drained from mined areas. The two highest total U concentrations in surface water in the region were from the Chinle Creek near Bluff watershed (362 µg/L) and Gallegos Canyon watershed (206 µg/L), the former having many U mines and the latter with none. The lack of an obvious effect from mining activity and U in the local geologic formations to the concentrations of U in the surface water suggests that another source could be the primary contributor of U to the San Juan River watershed.

Inverse lithography technology (ILT) based on the gradient descent (GD) algorithm, which is a classical local optimal method, can effectively improve the lithographic imaging fidelity. However, due to the low-pass filtering effect of the lithography imaging system, GD, although able to converge quickly, is prone to fall into the local optimum for the information in the corner region of complex patterns. Considering the high-frequency information of the corner region during the optimization process, this paper proposes a resolution layering method to improve the efficiency of GD-based ILT algorithms. A corner-rounding-inspired target retargeting strategy is used to compensate for the over-optimization defect of GD for inversely optimizing the complex pattern layout. Furthermore, for ensuring the manufacturability of masks, differentiable top-hat and bottom-hat operations are employed to improve the optimization efficiency of the proposed method. To confirm the superiority of the proposed method, multiple optimization methods of ILT were compared. Numerical experiments show that the proposed method has higher optimization efficiency and effectively avoids the over-optimization.

Basin morphometry, climate, and geology control how a hydrologic network evolves over time, controlling the efficiency of weathering of elements from geologic materials, and ultimately the input of sediment and dissolved constituents to river systems. Exceedances to the Navajo Nation surface water-quality standards for trace metals have been reported in the San Juan River watershed. Because metals are transported adsorbed to fine-grain sediment, the identification of areas with elevated sources of trace metals and/or areas with increased erosion and sediment transport potential is an important first step in protecting water quality. Physical factors such as elevation, slope, relief, and stream order were used to quantify morphometric parameters that effect the contribution of trace metals into the stream network. By correlating these parameters with water quality data that were collected from tributaries along the San Juan River, we identified statistically significant regressions between morphometric parameters and total Al, Pb, U, Fe, and Mn in surface water. Positive correlations with trace metals include tributary drainage basin perimeter, pour point elevation, and total number of streams, while negative correlations include stream length ratio, ruggedness number, and longest basin axis. Stream reach measurements within geologic units that contain known trace metal constituents reveal that Gallegos Canyon and Desert Creek are the most susceptible to sediment mobilization and transport, while other tributary drainage basins such as Desert, Recapture, and Salt Creeks are associated with naturally elevated concentrations of Al, As, Pb, and U.

Gravity-assisted effects are a critical controlling factor in enhancing oil displacement efficiency during gas flooding enhanced oil recovery (EOR). This study establishes a pore-scale mathematical model for hydrocarbon mixture gas displacement in oil-bearing porous media based on the Navier–Stokes equations, mass conservation principles, and porous media seepage theory. The model quantitatively characterizes the synergistic mechanisms of gravity assistance, dynamic velocity field evolution, molecular diffusion, and injection angle on EOR efficiency and CO2 sequestration. The results demonstrate that in heterogeneous porous media, the coupling of gravity and diffusion significantly mitigates non-uniform fluid flow by reducing the velocity disparity between main flow channels and corner regions, thereby expanding gas flooding sweep efficiency and enhancing CO2 storage performance. Under gravity-driven segregation, increasing the gas injection angle amplifies the vertical potential gradient between injectors and producers, favoring horizontal-dominated seepage of mixed gas. This increases oil recovery by 26.6% and the CO2 trapping amount by 2.15 × 10−3 mol. A larger oil–gas density difference strengthens gravity-assisted horizontal displacement, boosting recovery by 18.2% and the CO2 trapping amount by 4.71 × 10−3 mol. Additionally, a lower gas injection rate (2.0 × 10−5 m/s) improves oil recovery by 23.9% and increases the amount by 2.96 × 10−3 mol compared to a higher rate (8.0 × 10−5 m/s), as it promotes oil migration from secondary pores to main flow pathways. This research provides theoretical foundations and optimization strategies for synergistically improving oil recovery and geological CO2 sequestration via hydrocarbon mixture gas flooding.

Abstract Oceanic transform faults and their fracture zones are among the most striking features of ocean basins. Plate tectonics describes them as strike‐slip zones connecting mid‐ocean ridge segments. Still, no generally accepted theory exists for the lateral strain partitioning resulting in the deep and wide transform valleys and extensively tectonized inside corners. Here, we present results from multibeam bathymetry and a micro‐seismicity survey from the slow‐slipping Oceanographer transform on the Mid‐Atlantic Ridge near 35°N. Swath‐mapping echosounder data reveal a segmented transform fault. Away from the ridge‐transform intersections (RTI) and in the eastern half of the transform valley, micro‐earthquakes recorded on ocean‐bottom‐seismometers focus along the observed fault strands. Approaching the RTI, however, many micro‐earthquakes cut across the inside corner, while the active faults step toward the inside corner, paralleling the trend of the transform valley. Focal mechanisms point to extension in the inside corner region, while strike‐slip deformation is only recorded at distances larger than 15 km and away from the RTIs. These observations support a scenario in which deformation beneath a right‐angular ridge‐transform boundary at the seafloor develops into an oblique shear zone at depth, causing crustal thinning and consequently forming transform valleys. Away from RTIs, seismicity is focused on a narrow and segmented strike‐slip fault as predicted by plate tectonics. Oceanic transform faults are consequently not only strike‐slip but are also shaped by extensional processes, arguing for a revision of the concept of conservative plate boundaries to account for their morphology, segmentation, and significant lateral differences in seismic behavior.

Abstract. The West Antarctic Ice Sheet (WAIS) is the focus of current research due to its susceptibility to collapse, which could potentially contribute to rising sea levels. To accurately predict future glacier evolution, precise ice sheet models are essential. The ice discharge of outlet glaciers into the ocean is one key factor here, primarily caused by the basal sliding of ice. Since we cannot directly measure basal properties on a large scale, inverse models can be used to infer the basal drag coefficient by minimizing a cost function that depends on a velocity misfit and a regularization term. We conduct various basal drag inversions to obtain an improved basal drag distribution for the WAIS. Additionally, we perform L-curve analyses to determine the optimal trade-off between the cost function terms that result in smooth L-curves. The domain L-curve is divided into eight subdomains of the study area to assess how well the inverse method performs in different glaciological settings. Pine Island Glacier exhibits the smoothest L-curves, while slow-flowing regions such as Roosevelt Island reveal rather poorly shaped L-curve behavior for the basal drag inversion. This highlights the importance of performing a subdomain L-curve analysis for large-scale inversions to discover potential problematic regions and to establish suitable regularization for different physical conditions. Comprehensive basal drag inversion experiments allow us to test the dependence of both the L-curves and the basal drag results on the nonlinearity of sliding and the inclusion of subglacial effective pressure in the friction law. The analysis suggests that nonlinear friction laws are preferable to linear sliding because of reduced variance in the overall inferred friction coefficient and steeper L-curves leading to a more well-defined corner region. We show that a Budd-type friction law that incorporates effective pressure from a subglacial hydrology model rather than a simple geometry-based approximation achieves improved performance in our inverse model in terms of the total model variance ratio, along with faster convergence and smoother L-curves. Further comparison reveals that the basal drag coefficient field has a less variable spatial structure when an effective pressure from the hydrology model is used instead of a parameterized effective pressure, allowing us to interpret the inverted drag coefficient more precisely in terms of the basal properties rather than the basal hydrology.

Abstract Traditional corner detection methods are typically based on digital techniques. In this work, a metalens is cascaded with a liquid crystal device to rapidly switch between bright‐field imaging and corner detection modes in an optical device. Specifically, a conventional hyperbolic mode under left‐circularly polarized incidence is employed for bright‐field imaging and a focused second‐order vortex mode under right‐circularly polarized incidence for corner detection. At corner regions, overlapping double‐line edges form dual corner, and their center corresponds to the original corner in the image, serving as the basis for the detection mechanism. The tunable metalens offers a versatile and efficient platform for multifunctional optical imaging, with promising applications in defect detection, target recognition, and image matching.