Journal of Hydrodynamics最新文献

{"title":"Theoretical investigation of the simultaneous resonance of a cylindrical bubble under triple-frequency acoustic excitation","authors":"Jia-xin Yu,&nbsp;Zhi-hao Liu,&nbsp;Jin-xin Luo,&nbsp;Xiang-qing Zhang,&nbsp;Zheng-gui Li,&nbsp;Yu-ning Zhang","doi":"10.1007/s42241-025-0107-1","DOIUrl":"10.1007/s42241-025-0107-1","url":null,"abstract":"<div><p>In the present paper, the simultaneous resonance of a cylindrical bubble under triple-frequency acoustic excitation is investigated theoretically. Specifically, based on the multi-scale method, the dimensionless oscillation equations and the second-order analytical solutions of the primary-subharmonic-subharmonic (PRI-SUB-SUB), primary-superharmonic-superharmonic (PRI-SUPER-SUPER) simultaneous resonances are obtained. Based on the analysis of the frequency response, the nonlinear dynamic behavior of the cylindrical bubble and its influencing factors are analyzed. The primary conclusions include: (1) Under triple-frequency acoustic excitation, the frequency response of PRI-SUB-SUB presents a single peak, and that of PRI-SUPER-SUPER presents two peaks. (2) The polytropic exponent affects both the peak value and position of the resonance peak in the frequency response. (3) The unstable region in frequency response curve of the simultaneous resonance is significantly affected by the total amplitude and equilibrium radius, presenting a positive correlation.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"36 6","pages":"1095 - 1103"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513369","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":"Investigation on method of characteristics and semi-implicit method for pressure linked equations algorithms for water hammer based on unsteady friction","authors":"Zong-ku Liu,&nbsp;Guo-hong Wu,&nbsp;Hao Wang,&nbsp;Jia-xiang Zhang,&nbsp;Xue-lin Tang,&nbsp;Xiao-qin Li","doi":"10.1007/s42241-025-0105-3","DOIUrl":"10.1007/s42241-025-0105-3","url":null,"abstract":"<div><p>The misoperation of hydraulic components such as pumps and valves in pressurized pipelines triggers water hammer phenomena and seriously threats the safe operation of hydraulic systems. At present, the main water hammer simulation methods are method of characteristics (MOC), and further investigation of new algorithms is needed. Therefore, a new method for simulating the water hammer using the finite volume method (FVM), semi-implicit method for pressure linked equations (SIMPLE) algorithm is proposed in the present work. Compared with the experimental data, the accuracy and reliability of the proposed algorithm are verified. Results show that the IAB, MIAB friction models not only predict the first pressure peak but also accurately predict the pressure attenuation. From the comparison of the MOC, SIMPLE algorithms, the results of the two algorithms are almost the same in front of the valve, while near the upstream tank, when using the same friction model, the pressure attenuation predicted by the SIMPLE algorithm is slightly greater than that of the MOC method and closer to the experimental data. Therefore, the newly proposed algorithm can serve as an alternative to the MOC method in simulating water hammer. The investigation enriches the numerical methods of hydraulic transients and lays the foundation for subsequent program development.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"36 6","pages":"1155 - 1166"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513364","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 investigation on cavitation bubble precipitation characteristics in sand-laden water","authors":"Hao Wang,&nbsp;Ming Yang,&nbsp;Fu-jun Wang,&nbsp;Chao-yue Wang,&nbsp;Jian-zhong Zhu,&nbsp;Yi Zhang","doi":"10.1007/s42241-025-0110-6","DOIUrl":"10.1007/s42241-025-0110-6","url":null,"abstract":"<div><p>The cavitation bubble precipitation refers to the formation process of the spherical cavities, known as cavitation bubbles, as the ambient pressure of water decreases. In the fields of hydraulic machinery, the saturated vapor pressure of clean water is often used as the pressure threshold for cavitation occurrence. However, the engineering practice has demonstrated that, the incipient cavitation pressure may be significantly higher than the saturated vapor pressure, especially in sand-laden water conditions. Therefore, to determine a reasonable cavitation pressure threshold and ensure the accurate cavitation flow simulations and effective assessment of cavitation risks for hydraulic machinery operating in sand-laden water conditions, an experimental investigation is conducted. First, a high-precision experimental setup based on the vacuum pump, high-frequency pressure sensor and high-speed camera is constructed. This setup allows for the continuous pressure reduction in water, acquisition of high-precision pressure data and tracking of the entire cavitation bubble precipitation process. Second, based on the experiments in clean water conditions, the relationship between the cavitation bubble precipitation degree and pressure is established, and two key states of incipient cavitation and boiling cavitation are defined. Third, based on the experiments in sand-laden water conditions, it is observed that the numerous cavitation nuclei on sand surfaces make both the incipient and boiling cavitation pressure in sand-laden water higher than those in clean water. The quantitative relationship between the sand concentration and diameter, and the cavitation pressure is established, providing a more reasonable cavitation pressure threshold. This investigation enhances the understanding of cavitation bubble precipitation in sand-laden water and supports the development of more accurate cavitation models for hydraulic machinery operating in sand-laden water conditions.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"36 6","pages":"1033 - 1045"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513368","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 research on cavitating hydrodynamic characteristics of NACA0015 hydrofoil and its biomimetic counterpart","authors":"Xiao-jun Li,&nbsp;Shi-rui Tang,&nbsp;Zheng-dong Wang,&nbsp;Kui Chen,&nbsp;Yu-hua Zhou,&nbsp;Hai Chen","doi":"10.1007/s42241-025-0109-z","DOIUrl":"10.1007/s42241-025-0109-z","url":null,"abstract":"<div><p>The biomimetic hydrofoils are frequently employed to enhance cavitation performance, although the underlying mechanisms remain to be fully elucidated. This study utilizes a cavitation visualization experimental system and mechanical characterization to experimentally investigate the transient cavitation features of a NACA0015 hydrofoil and its biomimetic counterparts with modified lending-edge. The findings demonstrate that, in comparison with the flat hydrofoil, the biomimetic hydrofoil experiences a cavitation morphology transition at a lower cavitation number, with a reduction of up to 0.38. Moreover, the maximum cavity length and the maximum cavitation area are reduced by 17.11%, 17.32%, signifying a reduction in cavitation intensity. Proper orthogonal decomposition (POD) analysis revealed that the primary mechanism for the enhanced cavitation performance of the leading-edge wave structured biomimetic hydrofoil is the suppression of cloud cavitation shedding. At an attack angle of 6°, the biomimetic hydrofoil exhibited the highest lift coefficient increase of 18.56%, corresponding to a lift-to-drag ratio improvement of 9.56%. By analyzing the cavitation patterns of the two hydrofoils, it is evident that the rate of change in the maximum cavity length isolines for the biomimetic hydrofoil is lower than that of the flat hydrofoil. For an equivalent level of cavitation intensity, the biomimetic hydrofoil exhibits a lower cavitation number compared with the flat hydrofoil. These demonstrate that the wavy leading-edge design of the biomimetic hydrofoil effectively reduces the severity of cavitation, thereby confirming the efficacy of the biomimetic hydrofoil in enhancing cavitation performance.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"36 6","pages":"1046 - 1056"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513383","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":"A comprehensive comparison study between Deep Operator networks neural network and long short-term memory for very short-term prediction of ship motion","authors":"Yong Zhao,&nbsp;Jin-xiu Zhao,&nbsp;Zi-zhong Wang,&nbsp;Si-nan Lu,&nbsp;Li Zou","doi":"10.1007/s42241-025-0106-2","DOIUrl":"10.1007/s42241-025-0106-2","url":null,"abstract":"<div><p>Very short-term prediction of ship motion is critically important in many scenarios such as carrier aircraft landings and marine engineering operations. This paper introduces the newly developed functional deep learning model, named as Deep Operator networks neural network (DeepOnet) to predict very short-term ship motion in waves. It takes wave height as input and predicts ship motion as output, employing a cause-to-effect prediction approach. The modeling data for this study is derived from publicly available experimental data at the Iowa Institute of Hydraulic Research. Initially, the tuning of the hyperparameters within the neural network system was conducted to identify the optimal parameter combination. Subsequently, the DeepOnet model for wave height and multi-degree-of-freedom motion was established, and the impact of increasing time steps on prediction accuracy was analyzed. Lastly, a comparative analysis was performed between the DeepOnet model and the classical time series model, long short-term memory (LSTM). It was observed that the DeepOnet model exhibited a tenfold improvement in accuracy for roll and heave motions. Furthermore, as the forecast duration increased, the advantage of the DeepOnet model showed a trend of strengthening. As a functional prediction model, DeepOnet offers a novel and promising tool for very short-term ship motion prediction.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"36 6","pages":"1167 - 1180"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513190","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 bubble collapse behaviors near dual cylinders within confined spaces","authors":"Shao-wu Ma,&nbsp;Jun-wei Shen,&nbsp;Jia-ze Ying,&nbsp;Shu-rui Zhang,&nbsp;Yu-ning Zhang,&nbsp;Yu-ning Zhang","doi":"10.1007/s42241-025-0111-5","DOIUrl":"10.1007/s42241-025-0111-5","url":null,"abstract":"<div><p>This paper investigates the bubble collapse characteristics near dual cylinders within confined spaces. Firstly, the impacts on the bubble morphology, with respect to the bubble positions and the cylinder spacings, are explored using high-speed photography experiments. Subsequently, based on the circle theorem, the liquid velocity field is qualitatively analyzed and compared with the experimental bubble interface motion. Finally, employing the Kelvin impulse theory, an analysis of the variation in Kelvin impulse at various cylinder spacings is conducted, which shows good consistency with the bubble centroid movement. The main conclusions are summarized as follows: (1) High-velocity regions are observed on both sides of the bubble. Low-velocity regions are observed between the bubble and cylinders. As the cylinder spacing and the bubble abscissa increase, the liquid velocity in the high-velocity regions decreases, and the low-velocity regions expands. (2) The characteristics of the bubble cross-sectional roundness, interface displacement, and cross-sectional area are significantly affected by the cylinder spacing and the bubble abscissa. (3) As the bubble abscissa increases, the Kelvin impulse intensity initially rises rapidly and subsequently declines gradually to a fixed value. As the cylinder spacings increases, the Kelvin impulse intensity decreases.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"36 6","pages":"1021 - 1032"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513366","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":"Investigation on the cylindrical bubble dynamics near a wall with an arched bulge","authors":"Yu-fei Wang,&nbsp;Shu-zheng Hu,&nbsp;Zheng-yang Feng,&nbsp;Ya-bin Liu,&nbsp;Xiao-yu Wang,&nbsp;Yu-ning Zhang","doi":"10.1007/s42241-025-0108-0","DOIUrl":"10.1007/s42241-025-0108-0","url":null,"abstract":"<div><p>In this paper, the collapse dynamic properties of the cylindrical bubble near an arched cylinder bulge are researched relying on the conformal transformation and Kelvin impulse model. The properties of the liquid velocity distribution, Kelvin impulse distribution and the attraction zone of the jet are analyzed when the bubble and the bulge are arranged symmetrically and asymmetrically. The results show that, firstly, on the side of the bubble close to the bulge, there is a minimum collapse velocity of the bubble surface, which decreases as the bulge angle increases. In addition, the bulge’s effects on the Kelvin impulse strength and direction become larger as the bulge angle increases. When the bubble is incepted at the joint of the flat wall and the bulge, the impulse strength reaches its maximum. Finally, as the bulge angle increases from 45°–120°, the area of the jet attraction zone is gradually expanding, with its maximum width gradually increasing from 1.1–1.8 times the chord length of the bulge.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"36 6","pages":"1073 - 1082"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513381","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":"Efficient navigation of a robotic fish swimming across the vortical flow field","authors":"Hao-dong Feng,&nbsp;De-han Yuan,&nbsp;Jia-le Miao,&nbsp;Jie You,&nbsp;Yue Wang,&nbsp;Yi Zhu,&nbsp;Di-xia Fan","doi":"10.1007/s42241-025-0103-5","DOIUrl":"10.1007/s42241-025-0103-5","url":null,"abstract":"<div><p>Navigating efficiently across vortical flow fields presents a significant challenge in various robotic applications. The dynamic and unsteady nature of vortical flows often disturbs the control of underwater robots, complicating their operation in hydrodynamic environments. Conventional control methods, which depend on accurate modeling, fail in these settings due to the complexity of fluid-structure interactions (FSI) caused by unsteady hydrodynamics. This study proposes a deep reinforcement learning (DRL) algorithm, trained in a data-driven manner, to enable efficient navigation of a robotic fish swimming across vortical flows. Our proposed algorithm incorporates the LSTM architecture and uses several recent consecutive observations as the state to address the issue of partial observation, often due to sensor limitations. We present a numerical study of navigation within a Kármán vortex street created by placing a stationary cylinder in a uniform flow, utilizing the immersed boundary-lattice Boltzmann method (IB-LBM). The aim is to train the robotic fish to discover efficient navigation policies, enabling it to reach a designated target point across the Kármán vortex street from various initial positions. After training, the fish demonstrates the ability to rapidly reach the target from different initial positions, showcasing the effectiveness and robustness of our proposed algorithm. Analysis of the results reveals that the robotic fish can leverage velocity gains and pressure differences induced by the vortices to reach the target, underscoring the potential of our proposed algorithm in enhancing navigation in complex hydrodynamic environments.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"36 6","pages":"1118 - 1129"},"PeriodicalIF":2.5,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513374","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":"Numerical and analytical models for prediction of the local scour under pipelines","authors":"Andrey Epikhin,&nbsp;Igor Potapov,&nbsp;Aleksandr Petrov,&nbsp;Aleksandr Kukharskii","doi":"10.1007/s42241-025-0104-4","DOIUrl":"10.1007/s42241-025-0104-4","url":null,"abstract":"<div><p>This paper considers local scour around a pipeline under turbulent flow. The Navier-Stokes equations are solved with a shear stress turbulence model. The original bed deformation equation based on an analytical sediment transport model is used to describe the changes in the bottom surface. The proposed sediment transport equation is based on Coulomb’s friction law for granular flow, Prandtl’s friction law for turbulent flow, and agrees with a large number of phenomenological formulas by other authors. A numerical algorithm for solving the mathematical model of bed surface erosion is implemented in OpenFOAM. Numerical simulations of the problem show that under the influence of turbulent flow generated at the pipeline streamline, a characteristic bottom wave of low steepness appears, the parameters of which asymptotically agree with the experimental data. Based on the analysis of experimental and numerical studies of the considered case, an assumption about the self-similar behavior of the bed surface evolution is made. Based on this assumption, a new method of constructing the self-similar dependence of the bed surface on time and space coordinates is proposed. In the proposed approach, the average values of tangential bottom stresses are determined for a number of self-similar bottom surface shapes, and then the rates of change of bottom wave lengths and amplitudes are calculated using the proposed analytical model. A comparison with experimental data and numerical calculations shows that the solution error does not exceed a few percent and the computational time is reduced by up to 30 times.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"36 6","pages":"1130 - 1141"},"PeriodicalIF":2.5,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513371","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":"Laboratory investigation of flow behavior in an open channel with emerged porous rigid and flexible vegetation","authors":"Kashif Iqbal,&nbsp;Usman Ghani,&nbsp;Ghufran Ahmed Pasha,&nbsp;Nadir Murtaza,&nbsp;Muhammad Kaleem Ullah,&nbsp;Naveed Anjum","doi":"10.1007/s42241-025-0100-8","DOIUrl":"10.1007/s42241-025-0100-8","url":null,"abstract":"<div><p>This study aims to investigate the influence of various vegetation patches with varying porosities on the hydraulic properties of a vegetated open channel under subcritical flow conditions. This research work investigated three types of vegetation patches: Rigid, flexible, and a combination of the two. In total five vegetation patches with three different porosities for each patch were investigated. Effect of these vegetation patches on various hydraulic parameters such as backwater rise, energy reduction, water surface slope in the vegetation patch, hydraulic jump formation on the downstream side of the vegetation patch, reduction in fluid force index (RFI), moment index (RMI), overflow volume (Δ<i>Q</i>) were studied. The findings revealed that the backwater rise increased in the case of rigid patch as the initial Froude number increased, whereas it decreased in the case of flexible and combined vegetation patches. It was observed that as the porosity increased from low (<i>P</i>_<i>r</i> = 0.90) to high (<i>P</i>_<i>r</i> = 0.99), the backwater rise decreased for all vegetation patches. The relative energy reduction rate increased for the rigid patch and showed a reverse trend for the flexible and combined vegetation patches with increasing initial Froude number. In the combined vegetation arrangement, the energy reduction values were highest for the alternate rigid and flexible (ARF) vegetation patches and lowest for the longitudinal rigid and flexible (LRF) vegetation patches. This study identified the presence of a hydraulic jump downstream of the vegetation patch, as indicated by the Froude number in the range of 1.0–1.7. The study also found that RFI, RMI, Δ<i>Q</i> had the highest values of 19.05%, 19.05%, 80.20%. The results of this study provide insight into the impact of vegetation patches with varying porosities on open-channel flow characteristics and can help develop sustainable vegetation management strategies.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"36 6","pages":"1181 - 1199"},"PeriodicalIF":2.5,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513362","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}