Journal of Hydrodynamics最新文献

{"title":"Slotted endwall strategies for hump suppression and hydraulic performance improvement in semi-open centrifugal pumps","authors":"Jin-ling Lu,&nbsp;Rui-xue Han,&nbsp;Qing Liu,&nbsp;Jian Dong,&nbsp;Jian-jun Feng,&nbsp;Wei Wang","doi":"10.1007/s42241-026-0063-4","DOIUrl":"10.1007/s42241-026-0063-4","url":null,"abstract":"<div><p>Semi-open centrifugal pumps often experience hydraulic instabilities under low-flow conditions, manifested as the hump phenomenon in the head-flow curve. This instability arises from tip leakage vortices (TLV) and inlet recirculation (IR), which disturb the impeller inlet and cause energy losses. Although casing treatment has been widely applied in centrifugal compressors to suppress similar instabilities, its application in centrifugal pumps remains limited. To address this gap, the present study investigates slotted endwalls as a passive flow-control strategy to stabilize internal flow and suppress low-flow instabilities in semi-open impeller pumps. Three-dimensional simulations based on the Reynolds-averaged Navier-Stokes (RANS) equations and the shear stress transport (SST) <i>k</i>-<i>ω</i> (<i>k</i> denotes turbulent kinetic energy, <i>ω</i> denotes specific dissipation rate) turbulence model were performed and validated against experimental data with good agreement. Three slot configurations, namely arc, inclined polyline, and inclined slot, were designed to assess the geometric effects on TLV and IR. Results show that all designs effectively mitigate the hump phenomenon and extend the stable operating range, with the inclined slot achieving the best performance. It effectively eliminates the hump region and enhances the efficiency at both design and high-flow rates. Further analyses reveal that slotted endwalls promote smoother reentry of leakage flow and reduce energy dissipation. Orthogonal optimization identifies slot position as the dominant factor influencing performance. These findings confirm that slotted endwall modification is an effective and practical passive design approach for improving flow stability and hydraulic efficiency in semi-open centrifugal pumps.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"38 4","pages":"781 - 797"},"PeriodicalIF":4.0,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149099226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An adaptive time-scale-driven hybrid URANS/LES turbulence model for compressible flows: Development and application","authors":"Xu Han,&nbsp;Fu-jun Wang,&nbsp;Tian-yu Pan,&nbsp;Teng Li,&nbsp;Chao-yue Wang","doi":"10.1007/s42241-026-0064-3","DOIUrl":"10.1007/s42241-026-0064-3","url":null,"abstract":"<div><p>Hybrid unsteady Reynolds-averaged Navier-Stokes/large eddy simulation (URANS/LES) models are progressively being applied to compressible flow study due to the capability to balance computational cost with simulation accuracy, and have demonstrated significant prospect for future applications. As a recently developed hybrid URANS/LES model, the adaptive time-scale driven (ATSD) model is particularly suited for resolving rotating turbulence of turbomachinery owing to its adaptive time-scale-driven modelling strategy. However, when applied to compressible flows, such as in compressor rotors, the ATSD turbulence model may exhibit numerical instability and insufficient predictive accuracy stemming from the strong compressible effects. To address these limitations, this study proposes a novel ATSD-<i>ρ</i> (<i>ρ</i> denotes density) turbulence model, which incorporates the following enhancements specifically designed for compressible flows: (1) An implicit eddy viscosity adjustment strategy is used to enhance numerical stability. (2) Turbulence diffusion effect of density is considered to improve prediction accuracy. (3) An optimized characterization of the resolved time scale is utilized to reflect compressible flow adaptability. This new model is validated in two canonical transonic axial compressor rotor test cases, National Aeronautics and Space Administration (NASA) Rotor 67 and NASA Rotor 37, and the results demonstrate that the ATSD-<i>ρ</i> model improves the prediction accuracy of rotor aerodynamic performance while enhancing the resolution of finer-scale turbulent vortical structures, thereby providing an efficient solution for engineering computation of compressible turbulence.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"38 4","pages":"599 - 615"},"PeriodicalIF":4.0,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149099227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on the post-processing procedure of large-thickness tomographic particle image velocimetry measurement data in open-channel flows","authors":"Yong-qiang Wang,&nbsp;Peng Zhang,&nbsp;Sheng-fa Yang,&nbsp;Lin-xi Zeng","doi":"10.1007/s42241-026-0062-5","DOIUrl":"10.1007/s42241-026-0062-5","url":null,"abstract":"<div><p>To improve the reliability and accuracy of large-thickness tomographic particle imaging velocimetry (TPIV) measurement data in open-channel flows, a post-processing approach has been developed. This approach integrates statistical error correction with constraints derived from physical equations. This approach begins with the application of standard deviation techniques and the normalized median filter for the statistical refinement of the raw data. It is followed by a divergence correction based on the incompressible continuity equation, ensuring the conservation of mass in the flow field. The processing procedure and parameter selection for large-thickness TPIV measurement data in open-channel flows are comprehensively discussed. The results are then compared with theoretical data and traditional methods to validate the efficacy of this post-processing approach. The results reveal a strong correlation between the post-processed 3-D velocity field data and the theoretical benchmarks, as evidenced by the agreement in basic statistical quantities, uncertainty analysis, and power spectral distribution. Furthermore, the characterization of the flow field’s coherent structures is significantly enhanced following the post-processing procedure. This investigative framework presents a robust strategy for optimizing large-thickness TPIV measurement data in open-channel flows, thereby improving both the accuracy and efficiency of 3-D flow field analysis in the context of fluid dynamics research.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"38 4","pages":"730 - 748"},"PeriodicalIF":4.0,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149099034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CFD assessment of real-rotating and body-force propeller models for pure loss of stability in regular stern-quartering waves","authors":"Ke Zeng,&nbsp;Chen Yang,&nbsp;Tian-hua Wang,&nbsp;Shu-xia Bu,&nbsp;Wen-tao Wang","doi":"10.1007/s42241-026-0065-2","DOIUrl":"10.1007/s42241-026-0065-2","url":null,"abstract":"<div><p>Pure loss of stability (PLS) is a highly nonlinear stability failure mode, which usually happens in following and stern-quartering waves. It may interact strongly with the restoring moment variation, forward speed, propulsion, steering action, and roll-yaw coupling. Reliable prediction of PLS is important for direct stability assessment in the International Maritime Organization (IMO) second-generation intact stability criteria. To examine how propeller modeling affects viscous-flow prediction of this phenomenon, free-running CFD simulations in regular stern-quartering waves were carried out for a fully appended Office of Naval Research (ONR) tumblehome model. Two propulsion treatments were compared: A resolved rotating propeller model and a body-force propeller model. Self-propulsion calculations in calm water were first performed to determine the propeller revolutions for each target speed, and subsequent wave simulations were carried out with automatic rudder control. The two models gave comparable self-propulsion results and reproduced the main trend of increasing asymmetric roll response at different Froude numbers (<i>Fr</i>). A detailed comparison at critical <i>Fr</i> = 0.275 showed that the main difference between the two propeller models was not in the overall maximum roll amplitude, but in the transient development of the instability. The discretized propeller model predicted stronger port-starboard asymmetric characteristics in propeller thrust, rudder wetted area, and rudder moments when a large starboard roll led to appendage emergence, resulting in an earlier development toward capsize. In contrast, the body-force model delayed this process and showed higher computational efficiency. The present results clarify the influence of propeller modeling on the CFD prediction of pure loss of stability and provide guidance for selecting propeller models in direct viscous-flow simulations of extreme ship motions.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"38 4","pages":"666 - 677"},"PeriodicalIF":4.0,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149099036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of a spherical particle on cavitation bubble near a rigid wall under non-coaxial conditions","authors":"Si-yu Chen,&nbsp;Duan Chen,&nbsp;Han Hu","doi":"10.1007/s42241-026-0061-6","DOIUrl":"10.1007/s42241-026-0061-6","url":null,"abstract":"<div><p>The interaction between sand particles and cavitation bubbles near material surfaces under non-coaxial conditions is a common phenomenon when cavitation erosion occurs in sediment-laden water. Investigation into this phenomenon is of great significance for revealing the mechanism of cavitation erosion in sediment-laden flows. In this study, a low-voltage electric discharge device and a high-speed camera were adopted to investigate the influence of a spherical particle on the collapse characteristics of a cavitation bubble near a wall under non-coaxial conditions, including collapse morphology, collapse time, and migration behavior. The experimental results indicate that: (1) The side of the cavitation bubble surface close to the spherical particle surface exhibits delayed contraction, with the bubble surface elongated by the particle and partial surface splitting observed. (2) The collapse time of the cavitation bubble is prolonged under the influence of the spherical particle, showing a linear increase with the dimensionless parameter <i>αε</i> / (<i>γ</i>_p<i>γ</i>) (<i>α</i> is the angle, <i>ε</i> is the size ratio, and <i>γ</i>_p and <i>γ</i> are dimensionless distances to the particle and wall, respectively). (3) Non-coaxial particles alter the migration behavior of the cavitation bubble, including changes in the collapse direction and migration displacement. A critical condition formula for the cavitation bubble not collapsing toward the wall is proposed based on the relationship between <i>γ</i>_p<i>γ</i> and <i>α</i>. Furthermore, the variation of the cavitation bubble migration distance Z<span>\u0000 ^*_b\u0000 \u0000 </span> with the parameter <i>αε</i> / (<i>γ</i>_p<i>γ</i>) is summarized under different angles <i>α</i> and dimensionless distances <i>γ</i>_p, indicating that the migration of the cavitation bubble decreases as <i>αε</i> / (<i>γ</i>_p<i>γ</i>) increases. The findings of this study provide important insights into the interaction mechanisms between sand particles and cavitation bubbles in sediment-laden flows.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"38 4","pages":"771 - 780"},"PeriodicalIF":4.0,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149099033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of flow characteristics on mixing performance in continuous-operation eccentrically-stirred tank","authors":"San-xia Zhang,&nbsp;Chun Xiang,&nbsp;Jin Li,&nbsp;Yi Sun,&nbsp;Jun-hao Zhang,&nbsp;Jun-hao Zhou,&nbsp;Zhen-hua Duan,&nbsp;Jing Ma","doi":"10.1007/s42241-026-0056-3","DOIUrl":"10.1007/s42241-026-0056-3","url":null,"abstract":"<div><p>Within continuously and eccentrically stirred tanks, the correct prediction of fluid mixing behavior is strongly dependent on the resolution of highly complex, multi-scale hydrodynamic features. To address this challenge, this study adopts a high-fidelity computational fluid dynamics (CFD) framework, integrating the volume of fluid (VOF) method, a delayed detached-eddy simulation (DDES) turbulence model, the <i>Q</i>-criterion for vortex identification, and thermodynamic entropy production theory to analyze the multiphase flow of a urea-water mixture. A comparative performance evaluation between flat-blade and propeller impellers reveals that the flat-blade configuration yields superior mixing efficiency, as evidenced by shorter mixing times and distinct torque profiles. Mechanistically, the flat-blade impeller generates more intense and persistent trailing vortices that enhance localized fluid entrainment and promote global macro-circulation. Furthermore, multi-scale modal analysis via proper orthogonal decomposition (POD) demonstrates that macromixing performance is predominantly governed by dominant, large-scale coherent flow structures. Ultimately, these insights clarify the interdependence between transient flow topology and mixing kinetics, offering actionable design criteria for high-performance, continuous eccentric agitation system optimization.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"38 3","pages":"579 - 598"},"PeriodicalIF":4.0,"publicationDate":"2026-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148807248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prediction of discharge capacity in meandering compound channels covered with vegetation","authors":"Yi-sen Wang,&nbsp;Zhong-hua Yang,&nbsp;Wen-xin Huai,&nbsp;Meng-yang Liu","doi":"10.1007/s42241-026-0054-5","DOIUrl":"10.1007/s42241-026-0054-5","url":null,"abstract":"<div><p>Based on the existing flume-experimental records of meandering compound channels and explicitly accounting for the hydraulic influence of the floodplain vegetation, a machine-learning approach, namely genetic programming, was employed to derive a compact yet highly accurate discharge prediction equation. The resulting equation was compared against existing predictors and was subsequently interrogated, together with straight-compound-channel data, to quantify the individual influences of geometric and resistance parameters. Across the entire dataset for vegetated meandering compound channels, the new formula delivers a pronounced improvement in predictive accuracy, giving the smallest mean squared error and the substantially enhanced correlation coefficient. The sensitivity analysis identifies the main-channel sinuosity (<i>s</i>) and bed slope (<i>S</i>₀) as the dominant controls. The discharge decreases monotonically with increasing <i>s</i>, the width ratio of the main channel to the entire channel (<i>β</i>) and vegetation density (<i>φ</i>), whereas it increases with <i>S</i>₀. When <i>s</i> is low, the percentage reduction in discharge attributable to the increase in <i>s</i> intensifies with relative flow depth (<i>D</i>_r). Once <i>s</i> exceeds 1.5, the nondimensional reduction becomes essentially depth-independent.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"38 3","pages":"427 - 440"},"PeriodicalIF":4.0,"publicationDate":"2026-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148807667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The reason analysis for a non-typical storm surge disaster in the Bohai Sea using modeling, field observations, and satellite altimetry data","authors":"Yu-ling Liu,&nbsp;Zi-xuan Lang,&nbsp;Rui Zhang,&nbsp;Zhi-peng Li,&nbsp;Jie Zhao,&nbsp;Qiao-qiao Zhang,&nbsp;Ming-liang Zhang","doi":"10.1007/s42241-026-0055-4","DOIUrl":"10.1007/s42241-026-0055-4","url":null,"abstract":"<div><p>Storm surges are natural disasters affecting the social and economic development in coastal areas of the Bohai Sea. This study used the Delft model to construct a storm surge model for the Yellow and Bohai Seas. A storm surge occurring on October 18–22, 2024, caused by non-typical weather systems was comprehensively analyzed using simulations, observations, and satellite altimetry data. Wind data from the European Centre for Medium-Range Weather Forecasts (ECMWF) 5th Generation of European Reanalysis (ERA5) dataset were used as input into the numerical model. The results showed that the simulated astronomical tide levels and storm surges were similar to the observed data. The first and second stages of the storm surge in the Yellow and Bohai Seas were caused by a strong cold air mass, and the third stage was caused by cold air and the inertial oscillation of water. A decrease in the water level on the 19th and 20th caused the accumulation of a large amount of seawater in the southern Yellow Sea. The resulting potential energy gradient caused the excess seawater to reach the Dalian and Dandong coasts and the Bohai Sea. The southerly wind combined with the astronomical tide exacerbated this non-typical flood disaster. The inertial oscillation of water and wind contributed 66.7% and 33.3%, respectively, to the storm surges in the third stage, demonstrating the dominant effect of the inertial oscillation on the non-typical flood disaster.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"38 3","pages":"518 - 531"},"PeriodicalIF":4.0,"publicationDate":"2026-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148807245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shape optimization and CFD time-domain hydrodynamic performance of a pendulum wave energy buoy through free-form deformation and potential flow theory","authors":"Huan-zhe Liu,&nbsp;Shuo Huang,&nbsp;Yu Yao,&nbsp;Wei-qi Liu","doi":"10.1007/s42241-026-0060-7","DOIUrl":"10.1007/s42241-026-0060-7","url":null,"abstract":"<div><p>Pendulum wave energy converters harness wave energy via an articulated power take-off (PTO) system linking the wave-absorbing buoy to the fixed base. The geometric shape design of the buoy plays a critical role in determining the overall efficiency of wave energy capture. To further enhance the conversion efficiency of such devices under real-sea conditions, this paper introduces a rapid optimization method based on free-form deformation (FFD) and frequency-domain potential flow theory. First, the CAESES-GeniE-HydroD optimization framework is established by integrating a FFD technique with frequency-domain potential flow theory, enabling parametric modeling, geometric deformation, and hydrodynamic analysis of the buoy. Subsequently, the control points defining the buoy’s geometry are adjusted using the Non-dominated Sorting Genetic Algorithm II (NSGA-II), with the objective of maximizing the pitch response amplitude operator (RAO). Through iterative global optimization, the optimal buoy shape is identified under the given design conditions. Finally, computational fluid dynamics (CFD) simulations are performed to evaluate the time domain motion response of the optimized buoy, incorporating PTO damping under irregular wave conditions. The capture width ratio before and after the optimization is compared to assess the relative improvement. The results demonstrate that, compared with the initial wave-absorbing buoy, optimizing the wave-facing surface alone increases the capture width ratio by 58.28%, whereas simultaneous optimization of both the wave-facing and back-wave surfaces yields a 75.27% increase. These findings offer theoretical support for enhancing the power generation efficiency of wave energy conversion devices.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"38 3","pages":"488 - 502"},"PeriodicalIF":4.0,"publicationDate":"2026-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148807666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CFD analysis and maneuvering simulation of multi-connected pusher-barge system","authors":"Zihao Wang,&nbsp;Masaaki Sano,&nbsp;Hirokatsu Yamashita","doi":"10.1007/s42241-026-0059-0","DOIUrl":"10.1007/s42241-026-0059-0","url":null,"abstract":"<div><p>To reduce CO₂ emissions and alleviate labor shortage in the field of transportation, the modal shift should be further promoted by developing a new-type coastal ship. We have studied a multi-connected pusher-barge system (P/B) as one of the promising means of transportation. This P/B system was designed to connect at most three barges to a pusher in the longitudinal direction and to apply the operational flexibility of traditional inland P/B convoys to coastal shipping routes. The berthing time can be saved by enabling barges to join or leave the system at sea. Computational fluid dynamics (CFD) simulations were utilized to analyze maneuvering hydrodynamic forces and visualize flow fields (velocity and pressure) across different loading conditions. Based on these hydrodynamic analyses, turning and zigzag maneuvers were simulated using a mathematical model. The findings demonstrate that the system’s maneuverability is highly sensitive to the loading conditions of the barges.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"38 3","pages":"471 - 480"},"PeriodicalIF":4.0,"publicationDate":"2026-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148807664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}