Fluid Dynamics最新文献_第5页

Shock Response Spectrum Characteristics of Transient Fluid-Structure Interaction for High-Speed Water Entry Vehicle 高速入水飞行器瞬态流固耦合冲击响应谱特性

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-07-19 DOI: 10.1134/S0015462826604572

Z. L. Chen, X. G. Wang, X. Liu, X. D. Shao, J. Q. Tu

{"title":"Shock Response Spectrum Characteristics of Transient Fluid-Structure Interaction for High-Speed Water Entry Vehicle","authors":"Z. L. Chen, X. G. Wang, X. Liu, X. D. Shao, J. Q. Tu","doi":"10.1134/S0015462826604572","DOIUrl":"10.1134/S0015462826604572","url":null,"abstract":"The high-speed water entry of trans-media vehicles involves complex fluid-structure interactions; the strong nonlinearity of impact loads and structural dynamic responses poses core challenges for accurately characterizing impact environments and revealing shock response spectrum characteristics in the flight vehicle safety design. This paper utilizes the arbitrary Lagrangian–Eulerian (ALE) method to develop a high-fidelity predictive numerical model for simulating high-speed water entry impacts. The impact pressure, the cavitation evolution, and variations in the axial/normal forces are systematically analyzed by simulating the impact process. The acceleration time histories at critical measurement point are also extracted, and its shock response spectrum (SRS) is developed to characterize the frequency-domain attributes of the shock environment. Then, the effects of various water-entry velocities and angles are studied. The results show that the vehicle undergoes extreme transient loads during initial water entry, with the wetting pressure playing a critical role in multi-directional loading. Further analysis of the shock response spectrum reveals that the axial impact load (peak: 1.46 × 105 N) demonstrates a peak amplification factor of 1.409 at approximately 400 Hz, while a local monitoring point’s axial acceleration (peak: 762 g) exhibits a significantly higher amplification factor of 5.47 at around 30 kHz. Additionally, the increased speed and angle markedly alter the time-domain response characteristics, yet negligibly affect the peak amplification factor in the shock response spectrum. Instead, the primary effect is a shift in the peak frequency toward higher frequencies. These findings provide important insights for the structural design and protection of water-entry vehicles, highlighting the need to consider not only extreme load-induced damage but also resonance failure caused by specific frequency components.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermo-Fluid Behaviour and Irreversibility Analysis of Forced MHD Liquid Metal Flow past a Sphere with Uniform Heat Flux Condition 均匀热流条件下强迫MHD液态金属流过球体的热流体行为和不可逆性分析

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-07-19 DOI: 10.1134/S0015462826604560

N. K. Nath, R. Saha, B. H. S. Raju

{"title":"Thermo-Fluid Behaviour and Irreversibility Analysis of Forced MHD Liquid Metal Flow past a Sphere with Uniform Heat Flux Condition","authors":"N. K. Nath, R. Saha, B. H. S. Raju","doi":"10.1134/S0015462826604560","DOIUrl":"10.1134/S0015462826604560","url":null,"abstract":"The inherent high conductivity of liquid metals ensures efficient heat transfer, motivates the study of forced magnetohydrodynamic (MHD) flow past a sphere essential for advanced thermal management applications. This article presents a numerical investigation of thermo-physical characteristics, and entropy generation in liquid-metal MHD flow past a heated sphere under uniform heat flux (UHF) condition. A fourth-order accurate finite difference method is employed to discretize the Navier–Stokes equation coupled with the energy equation, implementing the pseudo-time iterative method. Among the highlighted results, the separation length and angle become non-monotonic against the interaction parameter (M) for each Reynolds number (({text{Re}} > 22)). The mean Nusselt number (overline {{text{Nu}}} ) shows a non-monotonic dependence on (M) with the transitions at a critical interaction parameter Mcr. Alongside, a correlation for calculating (overline {{text{Nu}}} ) has also been developed. Notably, the drop in heat transfer from (M = 0) to (M = {M_{{text{cr}}}}) is more significant under UHF compared to constant wall temperature condition (CWT), highlighting around 173% of drop under liquid lithium at Re = 200. The total entropy production is non-monotonic on sphere surface for every Re and (M). The Bejan number ({text{Be}}) decreases with increase in Re and (M), falling below 0.5 at Re = 200 for liquid lithium within the critical magnetic field regime ((M = 6{-} 8)).","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148613324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Computational Fluid Dynamics of Aerosol Deposition during High-Flow Nasal Cannula–Assisted Mask Nebulization: a Case-Based Study 高流量鼻导管辅助面罩雾化过程中气溶胶沉积的计算流体动力学：一项基于案例的研究

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-06-28 DOI: 10.1134/S001546282560436X

H. Li, F. H. Zheng, Y. Bian, J. L. Zhang, H. B. Liu

{"title":"Computational Fluid Dynamics of Aerosol Deposition during High-Flow Nasal Cannula–Assisted Mask Nebulization: a Case-Based Study","authors":"H. Li, F. H. Zheng, Y. Bian, J. L. Zhang, H. B. Liu","doi":"10.1134/S001546282560436X","DOIUrl":"10.1134/S001546282560436X","url":null,"abstract":"High-flow nasal cannula (HFNC) therapy, often combined with mask nebulization, enables uninterrupted oxygen delivery in acute respiratory care. However, the effects of the flow rate and the respiratory frequency on aerosol deposition remain elusive. A patient-specific upper-airway model is reconstructed based on high-resolution computed tomography. Computational fluid dynamics (CFD) simulations are conducted for the HFNC flow rates ranging from 0 to 50 L min–1 and respiratory rates of 16, 22, and 28 breaths min–1. The airflow patterns, the pressure distribution, and the regional aerosol deposition are analyzed. The aerosol deposition followed a unimodal distribution, peaking at 20 L min–1. At this flow rate, a coherent inspiratory jet enhance bronchial penetration, whereas the flow rates ≥ 40 L min–1 produce nasal vortices that divert ~12% of particles outward and suppress distal delivery. Aerosol deposition is mainly concentrated in the proximal airways (oropharynx 61%, trachea 18%, and nasal cavity 15%), with bronchial deposition remaining ≤3%. The lower respiratory rates markedly increase distal delivery by prolonging particle residence time; deposition at 16 breaths min–1 more than doubled compared with 28 breaths min–1. Although the airway resistance declines at the higher flow rates, the deposition efficiency remarkably decreases. CFD simulations revealed that aerosol deposition during HFNC-assisted mask nebulization could be influenced by the interaction between external flow and inspiratory dynamics. An HFNC flow rate of ~20 L min–1 maximizes pulmonary deposition at all breathing frequencies, while the lower rates further enhance bronchial delivery. These results challenge the assumption that a higher flow rate universally improves therapeutic outcomes and highlight the need for individualized HFNC flow adjustment to optimize aerosol delivery in clinical practice.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148323917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental Study of the Dynamic Behavior of Droplet Impact on Horizontal Cylindrical Surfaces 液滴撞击水平圆柱表面动力学行为的实验研究

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-06-28 DOI: 10.1134/S0015462826600124

Y. J. Xu, Z. H. Wan, G. Q. Wu, J. C. Zeng, X. F. Yin, Z. B. Zhang, Z. Y. Zhou, L. J. Guo

{"title":"Experimental Study of the Dynamic Behavior of Droplet Impact on Horizontal Cylindrical Surfaces","authors":"Y. J. Xu, Z. H. Wan, G. Q. Wu, J. C. Zeng, X. F. Yin, Z. B. Zhang, Z. Y. Zhou, L. J. Guo","doi":"10.1134/S0015462826600124","DOIUrl":"10.1134/S0015462826600124","url":null,"abstract":"High-speed imaging is used to investigate droplet impact dynamics on cylindrical surfaces, focusing on the effects of the impact height H, the initial diameter D0, and the wall roughness Ra on circumferential spreading. The results show the following: as H increases from 19 to 79 mm, the maximum circumferential spreading length increases by 39.02% on the inner surface and by 57.88% on the outer surface, the outer surface consistently exhibiting larger spreading due to convex geometry promoting circumferential flow. An increase in D0 from 2.11 to 3.34 mm enhances the maximum spreading length by 82.94% on the inner surface, while the spreading factor increases by 21.05% only, revealing a nonlinear dependence of the spreading factor on the droplet diameter. In contrast, wall roughness has a negligible effect within the tested range, suggesting inertia-dominated spreading. At higher impact conditions, finger-like splashing occurs, with a lower critical Weber number on the outer surface, attributed to enhanced air entrainment over convex geometries. In addition, droplet coalescence leads to prolonged oscillation and delayed stabilization on the outer surface, highlighting the role of curvature in energy dissipation. Correlations between the maximum spreading factor and the Weber number are established for predictive purposes. These findings provide insight into the droplet behavior on curved surfaces relevant to spray cooling and anti-icing applications.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148323672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigation of Spreading and Freezing during Sequential Droplet Impacts on an Inclined Ice Surface 倾斜冰面上液滴连续撞击过程中扩散和冻结的研究

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-06-28 DOI: 10.1134/S0015462826600136

Y. Liu, D. Wang, J. Wang, Z. Liu, J. Wang, Y. Shang, D. Li

{"title":"Investigation of Spreading and Freezing during Sequential Droplet Impacts on an Inclined Ice Surface","authors":"Y. Liu, D. Wang, J. Wang, Z. Liu, J. Wang, Y. Shang, D. Li","doi":"10.1134/S0015462826600136","DOIUrl":"10.1134/S0015462826600136","url":null,"abstract":"The impact and subsequent freezing of droplets on cold surfaces are critical phenomena in the aerospace, energy, and power industries, often compromising equipment integrity and operational performance. While dingle-droplet impacts have been extensively studied, systematic investigations into the sequential impact of multiple droplets—a more representative scenario in engineering applications—remain limited. In this work, we integrate experimental characterization with theoretical modeling to examine the impact, spreading, and freezing dynamics of two successive droplets on an inclined ice-covered aluminum substrate. Experiments were conducted across a range of inclination angles (0°–30°), surface temperatures (–30 to –15°C), and impact heights (20–50 cm). Our results reveal that the second droplet undergoes asymmetric spreading over the pre-frozen layer, governed by the coupled influence of thermal and geometric parameters on freezing duration. By applying energy conservation principles, we developed a theoretical model to predicts the maximum spreading diameter. This model incorporates key mechanisms, including dynamic contact angle evolution, ice-layer melting, and energy dissipation during phase change, achieving a prediction error within 2%. Furthermore, the observation that droplet behavior stabilizes after the third impact provides valuable theoretical insights and a robust predictive framework for the design of advanced anti-icing systems.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148323626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evolution of Surface Progressive Waves Propagating over a Sloping Wavy Seabed 在倾斜波浪形海床上传播的表面渐进波的演化

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-06-28 DOI: 10.1134/S001546282560316X

H. C. Wu, Y. Y. Chen, C. Y. Cheng

{"title":"Evolution of Surface Progressive Waves Propagating over a Sloping Wavy Seabed","authors":"H. C. Wu, Y. Y. Chen, C. Y. Cheng","doi":"10.1134/S001546282560316X","DOIUrl":"10.1134/S001546282560316X","url":null,"abstract":"To investigate the evolution of surface progressive waves propagating over a sloping wavy seabed, this study employes a perturbation expansion approach with three governing parameters, namely, the equivalent wave amplitude ({{a}_{0}}), the seabed slope (alpha ), and the amplitude of wavy seabed structures (b). These parameters are used to derive analytical solutions, including those under conditions involving the generation of reflected free waves, while avoiding singularities arising from resonant conditions in the wave field. Moreover, the reflected wave induced at the resonant point by a sloping wavy seabed is investigated. This resonance is amplified by the shoaling effect, which potentially contributes to the formation of large surges or freak waves. This amplification effect is stronger for longer-period waves near the coast and for steeper seabed slopes. When (b = 0), the solution reduces to the classical sloping seabed case, capturing the effects of wave shoaling, wave set-down, and return flow generation (caused by variations in the water depth). Alternatively, when (alpha = 0), the solution corresponds to a wavy seabed in a scenario involving a constant average water depth. In both limiting cases, the analytical solutions satisfy the principle of wave energy conservation. The reflection coefficients, including those associated with resonance, are determined in each limiting case. Comparisons with experimental and analytical results from the literature confirm the accuracy and applicability of the developed formula, especially under resonant conditions. The findings of this study provide theoretical insights into wave amplification mechanisms relevant to the generation of extreme waves near coastal zones.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 3","pages":""},"PeriodicalIF":0.7,"publicationDate":"2026-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148323623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Xe–He Plasma as an Active Medium of an Optically Pumped Rare Gas Laser 氦等离子体作为光抽运稀有气体激光器的有效介质

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-06-28 DOI: 10.1134/S0015462826604717

A. V. Juriev, Yu. A. Adamenkov, B. A. Vyskubenko, M. A. Gorbunov, A. A. Kalacheva, V. A. Shaidulina

引用次数: 0

Propagation of Stress and Pore Pressure in Fluid Saturated Viscoelastic Porous Media 流体饱和粘弹性多孔介质中应力和孔隙压力的传播

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-06-28 DOI: 10.1134/S0015462826604535

D. X. Yang

引用次数: 0

Study of Morphed Trailing-Edge Flaps for Wind Turbines 风力机变形尾缘襟翼研究

IF 0.7 4区工程技术

Fluid Dynamics Pub Date : 2026-06-28 DOI: 10.1134/S0015462826604389

R. Yin, J. B. Xie, J. Yao

引用次数: 0

Water Wave Propagation in the Presence of a U-Shaped Barrier 水波在u型障碍物存在下的传播

IF 0.6 4区工程技术

Fluid Dynamics Pub Date : 2026-05-29 DOI: 10.1134/S0015462826604274

S. Singh, R. B. Kaligatla, B. N. Mandal

{"title":"Water Wave Propagation in the Presence of a U-Shaped Barrier","authors":"S. Singh, R. B. Kaligatla, B. N. Mandal","doi":"10.1134/S0015462826604274","DOIUrl":"10.1134/S0015462826604274","url":null,"abstract":"In this paper, wave scattering by a U-shaped barrier and an inverse U-shaped barrier, both fixed in position and fully submerged in deep water, is illustrated. The Fredholm-type integral equations of the first kind are derived using the Havelock expansion of wave potentials and employing a matching technique. The wave reflection and transmission coefficients are derived in closed-form expressions. The integral equations are solved approximately using the Galerkin method with simple polynomials multiplied by exponential decay functions and appropriate weight functions as the basis functions. The computational results are validated against known results for a simple barrier configuration. The ways of affecting the barrier width and the submerged depth from the free surface on wave reflection, wave transmission, wave forces, and overturning moments are analyzed. The findings reveal that both barriers are highly wave-reflective over a wide range of incident wavelengths. The findings show reductions in the wave forces and the overturning moments with increases in the width and submerged depth of the barriers. These results are expected to be useful to engineers in the design of breakwaters in deeper depths.","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"61 2","pages":""},"PeriodicalIF":0.6,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0