Journal of Hydrodynamics最新文献

{"title":"Analysis of flow structure and air entrainment around a shallowly submerged hydrofoil based on third-generation vortex identification","authors":"Yu-ming Shao,&nbsp;Bo-wei Song,&nbsp;Jian-hua Wang,&nbsp;De-cheng Wan","doi":"10.1007/s42241-025-0023-4","DOIUrl":"10.1007/s42241-025-0023-4","url":null,"abstract":"<div><p>A shallowly submerged hydrofoil often induces disturbances on the free water surface by generating numerous vortex structures, leading to phenomena such as wave breaking and droplet splashing. These phenomena involve various physical mechanisms. In this study, the third-generation vortex identification technique, Liutex, is employed to perform a detailed analysis of the vortex structures generated by the hydrofoil near the free surface. It is observed that these coherent vortex structures strongly entrain surrounding fluid, resulting in air entrainment and bubble sweep-down phenomena. We analyze the bubble dynamics in terms of bubble number density, volume distribution, and number distribution, revealing the dynamic characteristics of bubbles under the influence of vortex structures. Additionally, by tracking the vortex structures, two distinct forms of air entrainment are identified. The analysis of bubble motion using Liutex demonstrates the evolution and distribution patterns of bubble sizes in the turbulent flow field. The results indicate that the third-generation vortex identification technique, Liutex, effectively explains the mechanisms behind free surface breaking induced by the shallowly submerged hydrofoil.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"37 2","pages":"246 - 255"},"PeriodicalIF":3.5,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843228","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":"Control of cloud cavitating flow around hydrofoils using local active oscillatory surfaces","authors":"Wei Wang,&nbsp;Ye-gao Qu,&nbsp;Hao Liu,&nbsp;Zhi-ke Peng","doi":"10.1007/s42241-025-0027-0","DOIUrl":"10.1007/s42241-025-0027-0","url":null,"abstract":"<div><p>Partial cavity oscillation is characterized by large-scale cavity shedding and intense pressure pulsations, causing severe damage to hydraulic machines. An incompressible homogeneous two-phase mixture numerical model is employed to investigate the effect of local active oscillatory surfaces on cavitating flows. The surfaces are positioned close to the cavity closure and simulated using an oscillatory velocity boundary to encumber the re-entrant jets. The results show that at high oscillation frequencies, the cavity shedding frequency synchronizes with the excitation frequency, indicating the presence of a lock-in mechanism. Meanwhile, the mean value and the fluctuation amplitude of the vapor volume are significantly reduced, indicating that the cavitation intensity and unsteady behaviors have been effectively weakened by the local active oscillation. Additionally, the high-pressure pulsation region diminishes, and the maximum pulsation amplitude declines. A simplified model manifests that the total vaporization and condensation rates of the entire domain exhibit a periodic variation in response to pressure pulsations. The dynamic mode decomposition (DMD) analysis reveals that small vortices shed from the main flow and dissipate under the influence of local oscillation. This study demonstrates that local active oscillatory surfaces are effective in inhibiting cloud cavitation.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"37 2","pages":"302 - 319"},"PeriodicalIF":3.5,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843232","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":"Experimental study of the wave–flow characteristics of internal solitary waves with different modes and their hydrodynamic forces on a horizontal cylinder","authors":"Shao-dong Wang,&nbsp;Hui Du,&nbsp;Zhe-yu Lu,&nbsp;Pai Peng,&nbsp;Gang Wei","doi":"10.1007/s42241-025-0026-1","DOIUrl":"10.1007/s42241-025-0026-1","url":null,"abstract":"<div><p>Internal solitary waves (ISWs) in oceans exist independently with different modes. Differences in ISW wave–flow characteristics with different modes create different structural damage mechanisms. In this work, physical simulations of first- and second-mode ISWs and their interactions with horizontal cylinders in the same stratified environment are carried out in the same physical flume. The experimental results reveal that under the same stratified environment and characteristic wave amplitude, the characteristic wave velocity and wavelength of the first-mode ISW are approximately three times greater than those of the second-mode ISW. The horizontal positive velocity and change rate of the first-mode ISW are lower than those of the second-mode ISW, and the horizontal negative corresponding value is greater than that of the second-mode ISW. In comparison, the vertical velocity is lower than that of the second-mode ISW. The first- and second-mode ISW loads increase with increasing characteristic wave amplitude. The maximum horizontal force of the second-mode ISW on the cylinder near the centre of the pycnocline is more significant than that of the first-mode ISW, whereas the vertical force of the former is smaller than that of the latter. The second-mode ISW has the spatial distribution characteristics of the peak value of the first-mode force exerted by the first-mode ISW of the convex and concave types simultaneously. The vertical and density profiles of the horizontal velocity induced by the propagation of different ISW modes in the same fluid environment are different, which leads to changes in the spatial distribution characteristics of the horizontal and vertical forces on the cylinder for different ISW modes. These results improve the understanding of ISW mechanisms with different modes on marine structures.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"37 2","pages":"281 - 293"},"PeriodicalIF":3.5,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843231","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":"Liutex-shear interaction in Lamb-Oseen vortex and three-dimensional cylinder flow at Re = 3 900 simulated with SWLBM","authors":"Xue-sen Chu,&nbsp;Shang Jiang,&nbsp;Jian-song Zhu,&nbsp;Yi-qian Wang","doi":"10.1007/s42241-025-0022-5","DOIUrl":"10.1007/s42241-025-0022-5","url":null,"abstract":"<div><p>With the development of Liutex theory, new applications have emerged, making it an effective tool for identifying and quantifying vortex structures in various fluid flows. The Liutex method provides precise information on vortex strength, size, and location, and enables real-time analysis of vortex evolution and interactions, enhancing the understanding of complex flow patterns. Based on the incompressible Navier-Stokes equations, we derived the Liutex-shear interaction equation by incorporating the Liutex-shear decomposition into the vorticity transport equation to explore the fundamental relationship between Liutex and shear. We first applied it to the two-dimensional Lamb-Oseen vortex, which has an analytical solution, to validate the previously introduced idea of using high dissipation regions to identify vortex boundaries. Then we conducted numerical experiments on a three-dimensional cylindrical flow at <i>Re</i> = 3 900. We computed the key terms in the Liutex-shear interaction equation for comparative analysis, and demonstrate that the Liutex-shear interaction equation offers a clearer insight into the nature of vortices. Utilizing the Sunway TaihuLight supercomputer, we performed large eddy simulations with 2.5×10⁸ grids for the three-dimensional cylindrical flow case, allowing Liutex to reveal more refined vortex structures in turbulence. These findings confirm that the conclusions obtained in two-dimensional cases are consistent with those in three dimensions and show that shear stretching significantly influences the Liutex-shear interaction, enabling us to approximately predict the evolution of the source term.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"37 2","pages":"230 - 238"},"PeriodicalIF":3.5,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843225","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":"3-D numerical study on the influence of orifice arrangement on sediment transport upstream of a dam","authors":"Zhuo Cheng,&nbsp;Xin-hua Lu,&nbsp;Rui Wang","doi":"10.1007/s42241-025-0021-6","DOIUrl":"10.1007/s42241-025-0021-6","url":null,"abstract":"<div><p>Multiple orifices set on a dam are commonly used for flood discharge and sediment removal. Different arrangements of orifices may lead to different scalar or sediment transport process in the near dam reservoir region. 3-D numerical simulations are implemented to simulate flow and sediment transport near an idealized rectangular dam region with a focus on the influence of orifice arrangement on scalar and sediment transport under a same flow discharge and concentration condition. It is found that the concentration distribution in the near dam reservoir region and the transport flux at the dam-site may change dramatically due to different arrangements of orifices. The effect of orifice arrangement on scalar and sediment concentration distribution in the near dam reservoir region is found to be limited roughly within a range of <span>((15-20)sqrt{sum{A}})</span> away from the dam where Σ<i>A</i> is the total area of all opened orifices on a dam. Under the same inlet water flow and concentration condition and at a steady state, for scalar transport, the transport flux at the dam-site may be independent of orifice arrangement; while for sediment transport with considering the settling effect, the transport flux is generally larger in cases with one orifice except when the orifice centroid elevation is sufficiently high. This work may provide guidance for reservoir regulation, e.g., to discharge more sediment downstream a reservoir or adjust local sedimentation distribution near the dam.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"37 2","pages":"347 - 358"},"PeriodicalIF":3.5,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843311","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":"Vortex-induced vibration response of dual-step cylinders with varied coverage","authors":"Jia-hang Lyu,&nbsp;Zhi-meng Zhang,&nbsp;Chun-ning Ji,&nbsp;Ya-wei Zhao,&nbsp;Hang-hao Zhao,&nbsp;Mu-yuan Du","doi":"10.1007/s42241-025-0020-7","DOIUrl":"10.1007/s42241-025-0020-7","url":null,"abstract":"<div><p>Vortex-induced vibration (VIV) of a dual-step cylinder with a diameter ratio of (<i>D</i> / <i>d</i> = 2) at different coverage ratios (<i>R</i> = 0%–100%) are experimentally investigated at Reynolds number (<i>Re</i> = 490–3 750). The general vibration responses of the dual-step cylinder at different coverage ratios can be classified into three categories based on the dominance of the small or large cylinder section: (1) Dominated by small cylinder (<i>R</i> = 4%), where the response and forces show a similar trend to that of a uniform small cylinder. The vortex shedding frequency and the drag frequency lock-in at the lower branch. (2) Transitional stage (<i>R</i> = 12.5%–25%), where competition between the large and small cylinder sections exists. The vibration responses show two “lock-in” regions in the transition branch and the lower branch. The lift and drag coefficients are double-peaked. (3) Dominated by the large cylinder (<i>R</i> = 50%–75%), where the initial branch of the response disappears, as replaced by the transition branch. The vibration frequency is still featured by two “lock-in” regions while the drag coefficient returns to the single-peak pattern, similar to that of the uniform large cylinder. The effective added mass significantly influences the vibration responses of the dual-step cylinder and it varies with the reduced velocity. A unified lock-in region is identified where the dimensionless vibration frequency consistently equals the unity, indicating a synchronization between the vibration frequency and the real natural frequency.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"37 2","pages":"331 - 346"},"PeriodicalIF":3.5,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843310","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 gap width on turbulent transition in Taylor-Couette flow","authors":"Chang-quan Zhou,&nbsp;Hua-Shu Dou,&nbsp;Lin Niu,&nbsp;Wen-qian Xu","doi":"10.1007/s42241-025-0019-0","DOIUrl":"10.1007/s42241-025-0019-0","url":null,"abstract":"<div><p>Simulations of the transitional flow in Taylor-Couette configuration are carried out to study the effect of the gap width on turbulent transition. The research results show that, under the same radius and the rotating speed of the inner cylinder, as the gap width increases, the flow becomes more stable. It is discovered that the average velocity distribution in the gap approaches the free vortex flow as the width increase and the stability of the flow is enhanced. It is found that, as the gap width increases, the maximum of the energy gradient function (from the energy gradient theory) in the gap decreases, which delays the turbulent transition. As such, the larger the gap width, the later the transition occurs. As the gap width increases, the Reynolds number based on the gap width alone is not able to characterize the flow behavior in Taylor-Couette flows, and the effect of the radius ratio should be taken into account.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"37 2","pages":"294 - 301"},"PeriodicalIF":3.5,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843238","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":"Improved design and model experimental verification of centrifugal blade profile based on flow analysis","authors":"Qi Gu,&nbsp;Hong-xun Chen,&nbsp;Zheng Ma","doi":"10.1007/s42241-025-0016-3","DOIUrl":"10.1007/s42241-025-0016-3","url":null,"abstract":"<div><p>In order to improve the efficiency of the centrifugal pump, this paper employs numerical simulation to study the internal flow of a centrifugal pump model with a specific speed ns=65.6. Based on the flow analysis results, flow control strategies are proposed, and a “bulged” impeller with a special blade pressure surface profile is designed. Research is conducted on the internal flow of the “bulged” impeller centrifugal pump, while the entropy production method is employed for a quantitative analysis of energy losses in various flow components. The results indicate that compared with the original impeller centrifugal pump, the total entropy production in the front chamber, back chamber, volute, and outlet pipe of the “bulged” impeller centrifugal pump is reduced. Additionally, the separation vortex on the pressure surface of the “bulged” impeller blade disappears, and the entropy production on the blade wall surface decreases. The study of the internal pressure fluctuation intensity in the centrifugal pump found that the pressure fluctuation intensity at various monitoring points within the impeller and volute of the “bulged” impeller centrifugal pump is reduced, leading to improved dynamic performance. Experimental results of the centrifugal pump show that the “bulged” impeller centrifugal pump exhibits a significant increase in efficiency from low flow to design flow conditions.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"37 2","pages":"388 - 393"},"PeriodicalIF":3.5,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843236","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":"Vortex visualization of tropical cyclones by Liutex","authors":"Oscar Alvarez,&nbsp;Chenxi Ma,&nbsp;Sim Aberson,&nbsp;Chaoqun Liu","doi":"10.1007/s42241-025-0018-1","DOIUrl":"10.1007/s42241-025-0018-1","url":null,"abstract":"<div><p>Analysis of the flow field of tropical cyclones in the mature stage by the Liutex methods, such as the Omega Liutex and the Liutex core line, is reported. This is the first known study analyzing tropical cyclones with the Liutex method. Liutex has the potential to enable greater understanding of tropical cyclone dynamics and to improve forecasts of their track, intensity, and structure.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"37 2","pages":"239 - 245"},"PeriodicalIF":3.5,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843237","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":"Vortex dynamics mechanism of the staggered impeller suppressing pressure fluctuations in a double-suction centrifugal pump","authors":"Jin-hao Liu,&nbsp;Dong-sen An,&nbsp;Jian-zhong Zhu,&nbsp;Yi Zhang,&nbsp;Qing-long Zhu,&nbsp;Fu-jun Wang,&nbsp;Chao-yue Wang","doi":"10.1007/s42241-025-0017-2","DOIUrl":"10.1007/s42241-025-0017-2","url":null,"abstract":"<div><p>The fact that the staggered impeller of a double-suction centrifugal pump can effectively suppress pressure fluctuations has been proved by engineering practice, but the flow mechanism behind it is still not fully understood. In this study, numerical simulations with a proof experiment were conducted, and the vortex dynamics analyses were performed using the newly developed rigid vorticity (Liutex) theory. The following valuable results are obtained: (1) In terms of the intuitive vortex structure, each blade of the impeller induces a trailing vortex rope with a strong rigid vorticity, which gradually evolves inside the volute casing with the rotation of the impeller. The trailing vortex ropes of the symmetric impeller are symmetrically distributed, while those of the staggered impeller present a staggered distribution, and the latter corresponds to a relatively lower rigid vorticity. (2) In terms of the correlation between the vortex and the pressure, the high rigid vorticity zone corresponds to the low-pressure zone. For a fixed point in the volute casing, there is a major “falling-rising” fluctuation in pressure as the symmetric vortex ropes transit it simultaneously, and a minor “falling-rising” fluctuation in pressure as the staggered vortex ropes transit it successively, corresponding to a lower peak-to-peak value of the pressure fluctuations. (3) In terms of the relation between the vortex and the velocity, the vortex ropes induced by the left and right impellers are counter-rotating and develop along the radial direction. This pattern results in high-speed zones at the middle part of the cross-section of the volute casing, both in the streamwise and radial directions, and contributes to velocity fluctuations due to the evolving vortex rope. However, the staggered distribution of vortex ropes can weaken the coupling of vortex pairs, thereby causing lower velocity and pressure pulsations, but can make the main frequency twice that of the symmetric impeller. This study enriches our physical knowledge by revealing the vortex dynamics mechanism of the staggered impeller of a double-suction centrifugal pump to suppress pressure fluctuations.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"37 2","pages":"209 - 229"},"PeriodicalIF":3.5,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843239","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}