International Journal of Multiphase Flow最新文献

{"title":"Regenerative Orr mechanism yielding large non-modal perturbation energy growth in a viscosity stratified plane shear flow","authors":"Sharath Jose","doi":"10.1016/j.ijmultiphaseflow.2024.105001","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105001","url":null,"abstract":"<div><p>Transiently growing non-modal perturbations can play a crucial role in the transition of plane shear flows in modally stable regimes. In terms of the extent of transient amplification, three-dimensional perturbations are typically more prominent due to the lift-up effect. In contrast, two-dimensional (2D) spanwise-independent perturbations are often considered less important as they typically undergo modest levels of transient growth and are short-lived. The Orr mechanism is key to the amplification of energy for 2D perturbations. In this work, we discuss 2D non-modal perturbations of three-layer viscosity stratified flows with the mean shear rates of the outer layers being equal. Strikingly, a novel regenerative Orr mechanism is found that allows for significant amount of energy amplification despite the 2D nature of the perturbations. Moreover, these perturbations survive for considerably long times. The perturbation structure shows symmetry about the middle layer and evolves such that the Orr mechanism can repeatedly occur in a regenerative manner resulting in the perturbation energy evolving in a markedly non-monotonic fashion. When these same perturbations are introduced in a uniform plane shear flow, the corresponding non-modal transient amplifications are shown to be much smaller.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 105001"},"PeriodicalIF":3.6,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142274088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular dynamics study of the mechanism of explosive boiling on hybrid wettability surfaces","authors":"Hongren Zhan,&nbsp;Dongling Liu,&nbsp;Baichen Ji,&nbsp;Debin Liu,&nbsp;Zhigang Zhang,&nbsp;Xianzhen Zhang","doi":"10.1016/j.ijmultiphaseflow.2024.105002","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105002","url":null,"abstract":"<div><p>In this work, molecular dynamics (MD) simulation is applied to study the effect of heating surfaces with different hydrophobicity occupancy ratios (the ratio of the surface area of hydrophobic spots to the total area of the heating surface) on the boiling process of the liquid film explosion. At the same time, the mechanism is revealed from the trajectory of argon atoms. The simulation results showed that the onset of explosive boiling was later for purely hydrophilic surfaces than for hybrid wettability surfaces with a hydrophobicity percentage of &lt;11%. The earliest onset of explosive boiling was observed for the heated surfaces with a hydrophobicity ratio of 6%. In addition, it was found that the superheat required for explosive boiling tended to decrease first and then increase with the gradual increase of the hydrophobicity ratio. Hydrophobic spots arranged on the surface provided bubble nucleation earlier for explosive boiling while enhancing convective heat transfer and thermal perturbation. The critical heat flux (CHF) of the heated surfaces with a hydrophobicity ratio of &lt;11% were all greater than that of the purely hydrophilic surfaces, and all reached the CHF before the purely hydrophilic surfaces.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 105002"},"PeriodicalIF":3.6,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142244093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 pressure drop characteristics of adiabatic two-phase flow in a Gyroid-structured channel","authors":"Tomoki Hirokawa,&nbsp;Hajime Miyata","doi":"10.1016/j.ijmultiphaseflow.2024.104982","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.104982","url":null,"abstract":"<div><div>Recent advancements in additive manufacturing techniques have enabled the fabrication of intricate structures. Among these structures, triply periodic minimal surfaces (TPMSs) such as the gyroid, are particularly promising for heat and mass transfer applications owing to their higher surface area to volume ratios compared to conventional structures such as heat exchangers. This study experimentally investigates the pressure drop characteristics of single- and two-phase flows in a gyroid-structured channel under adiabatic conditions. In particular, using an additively manufactured test section with a gyroid-structured channel, the pressure drop characteristics of both single- and two-phase flows are analyzed. The results ofsingle-phase flow experiments reveal that the friction factor depends on the hydraulic diameter, which is defined by the internal volume and surface area of the channel. This suggests that in addition to the hydraulic diameter, other parameters such as porosity and wall thickness must also be considered. Subsequently, the two-phase pressure drop predictions of homogeneous and separated models are compared with the pressure drop data obtained from two-phase flow experiments. The results reveal that gas–liquid separation must be considered to accurately predict the pressure drop in regions influenced by gravitational effects. Furthermore, correlations for predicting the pressure drops both single- and two-phase flows within the operating constraints are proposed.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 104982"},"PeriodicalIF":3.6,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling aerodynamic forces and torques of spheroid particles in compressible flows","authors":"Yibin Du ,&nbsp;Ming Yu ,&nbsp;Chongwen Jiang ,&nbsp;Xianxu Yuan","doi":"10.1016/j.ijmultiphaseflow.2024.104996","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.104996","url":null,"abstract":"<div><p>In the present study, we conduct numerical simulations of compressible flows around spheroid particles, for the purpose of refining empirical formulas for drag force, lift force, and pitching torque acting on them. Through an analysis of approximately a thousand numerical simulation cases spanning a wide range of Mach numbers, Reynolds numbers and particle aspect ratios, we first identify the crucial parameters that are strongly correlated with the forces and torques via Spearman correlation analysis, based on which the empirical formulas for the drag force, lift force and pitching torque coefficients are refined. The novel formulas developed for compressible flows exhibit consistency with their incompressible counterparts at low Mach number limits and, moreover, yield accurate predictions with average relative errors of less than 5%. This underscores their robustness and reliability in predicting aerodynamic loads on spheroidal particles under various flow conditions.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 104996"},"PeriodicalIF":3.6,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding solid particle transport in a gas cyclone separator","authors":"M. Sommerfeld,&nbsp;M.A. Taborda","doi":"10.1016/j.ijmultiphaseflow.2024.104992","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.104992","url":null,"abstract":"<div><div>A cyclone separator is a widespread device used in many industrial areas and daily life for removing fine particulate matter from a gas stream. This separator has been used for more than 100 years due to its simple and robust design, but was continuously further developed and adapted to specific applications. The mostly used configuration is the reverse flow type cyclone exhibiting however, a very complex vortex flow with high turbulence. In the past numerous experimental as well as numerical studies were conducted for optimising cyclone geometry with the goal of improving the separation efficiency. In most of the numerical studies done so far not all the relevant transport mechanisms affecting particle motion were considered. Therefore, a thorough numerical investigation is presented using an LES-point-particle-Euler/Lagrange approach with momentum 2-way coupling for analysing the effects of particle-scale transport processes on the performance of a 290 mm Stairmand type of cyclone. All simulations presented here were conducted for an inlet velocity of 10 m/s. The sub-grid-scale (SGS) turbulence was described by a dynamic Smagorinsky model. Particle transport was computed considering all relevant forces and modelling also SGS dispersion. For the first time, the influence of particle collisions with rough walls, modelled according to the stochastic approach presented by Sommerfeld and Huber (International Journal of Multiphase Flow, Vol. 25, 1457-1489, 1999), was analysed in detail with respect to the performance of a cyclone separator. Moreover, inter-particle collisions were described through the efficient stochastic model introduced by Sommerfeld (International Journal of Multiphase Flow, Vol. 27, 1828-1858, 2001). Specifically, the importance of the interplay between rough wall collisions and inter-particle collisions is highlighted in this contribution. Three different particle size spectra were considered with log-normal size distributions ranging up to 20 μm (mean diameter 5.21 μm), up to 60 μm (mean diameter 15.43 μm), and up to 100 μm (mean diameter 25.71 μm); each case with different mass loading. Naturally, due to their different inertia, the effects of wall collisions and inter-particle collisions are also different for these types of particles. After a thorough validation, the influences of two-way coupling, particle rough wall collisions (three surface roughness degrees) and inter-particle collisions are analysed and elucidated. It is shown that specifically surface roughness has a huge effect on the grade efficiency of a cyclone and cannot be neglected, as done in most numerical cyclone studies done so far. Inter-particle collisions may partly compensate the deterioration of separation by wall roughness.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 104992"},"PeriodicalIF":3.6,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trigger mechanism for a singing cavitating tip vortex","authors":"Zhaohui Qian ,&nbsp;Yongshun Zeng ,&nbsp;Xiaoxing Peng ,&nbsp;Xianwu Luo","doi":"10.1016/j.ijmultiphaseflow.2024.104995","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.104995","url":null,"abstract":"<div><p>The discrete tone radiated from tip vortex cavitation (TVC), known as ‘vortex singing’, was recognized in 1989, but its triggering remains unclear for over thirty years. In this study, the desinent cavitation number and viscous correction are applied to describe the dynamics of cavitation bubbles and the dispersion relation of cavity interfacial waves. The wavenumber-frequency spectrum of the cavity radius from the experiment in <em>CSSRC</em> indicates that singing waves predominantly consist of the stationary double helical modes (<em>k_θ</em> = 2^- and -2⁺) and the breathing mode (<em>k_θ</em> = 0^-), rather than standing waves as assumed in previous literatures. Moreover, two trigger mechanisms, expressed by two triggering lines, are proposed: the twisted TVC, initially at rest, is driven into motion through the corrected natural frequency (<em>f_n</em>) due to the step change of the far-field pressure. Subsequently, the frequency associated with the zero-group-velocity point (<em>ῶ_zgv</em>) at <em>k_θ</em> = 0^- is excited through <em>ῶ_i</em>, the frequency at the intersection of dispersion curves at <em>k_θ</em> = 0^- and -2⁺, or <em>ῶ_j</em>, the frequency at the intersection of dispersion curves at <em>k_θ</em> = 0^- and 2^-, corresponding to two types of the vortex singing triggering. These solutions, without empirical parameters, are validated using singing conditions provided by <em>CSSRC</em> and <em>G.T.H.</em>, respectively. Furthermore, the coherence and the cross-power spectral density spectrum indicates a large-scale breathing wave propagating along the singing cavity surface and travelling from downstream to hydrofoil tip, providing us a comprehensive understanding for the triggering of vortex singing.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 104995"},"PeriodicalIF":3.6,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142244092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 GFMxP and the basic extrapolation of the ghost values to solve the Poisson equation for discontinuous functions","authors":"Sandro Ianniello","doi":"10.1016/j.ijmultiphaseflow.2024.104997","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.104997","url":null,"abstract":"<div><p>In a recent paper, a novel coding of the Ghost Fluid Method for the variable coefficient Poisson equation with discontinuous functions (named GFMxP) was proposed. A lot of numerical tests, with all the required quantities available in a analytic form, were used to demonstrate the ability of the new procedure in modeling a sharp interface and to check the accuracy order of the solutions. In practical applications, however, the real difficulty stands in the estimation of the so-called “ghost values”, that is the values at points where the function is not only unknown, but even not defined. These values allow to compute the corrective terms enabling the use of standard finite difference formulas in presence of a singularity and/or a discontinuity, and can be only determined through some extrapolation procedure, whose truthfulness is essential to achieve a reliable result. The paper deals with such a basic issue, by testing different numerical strategies and demonstrating the strict relationship between the order of the adopted fit-model, the order of the solving scheme for the Poisson equation and the accuracy of the final solution.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 104997"},"PeriodicalIF":3.6,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142173505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Description of phase separation motion in gas‒liquid two-phase flow","authors":"Xitong Wu,&nbsp;Chenhao Li,&nbsp;Xingqi Luo,&nbsp;Jianjun Feng,&nbsp;Like Wang","doi":"10.1016/j.ijmultiphaseflow.2024.104998","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.104998","url":null,"abstract":"<div><p>Understanding the physics of phase separation between gas and liquid phases as a mixture mass has long been a challenge. In this paper, a phase separation description criterion based on heterogeneous flow model is proposed. A mathematical method similar to Lagrangian coherent structure (LCS) is used to identify the two-phase separation process, which is called relative motion Lagrangian coherent structure (rLCS). The rLCS is able to describe the dynamic evolution of the phase separation process and flow pattern transition in multiphase flows, which is very common in gas‒liquid mixture transportation and industrial processes. The most striking finding of rLCS is that phase separation and phase distribution are not in the same spatial position, that is, the process and the result of separation may not be exactly corresponding as we thought. This new flow structure reflects the underlying dynamic behavior of the multiphase flow field. In addition, the phase separation process has obvious periodicity. This paper reveals the typical phase separation process in the simulation of gas‒liquid two-phase pipe flow and gas‒liquid multiphase pump. These are very important to improve the understanding of multiphase flow processes, and can also lay a solid foundation for future flow control based on multiphase flow characteristics, highlighting the application potential of the new method.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 104998"},"PeriodicalIF":3.6,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142274087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 and modelling of hydrodynamics and heat transfer in flow boiling in normal and microgravity conditions","authors":"Paul Onubi Ayegba,&nbsp;Julien Sebilleau,&nbsp;Catherine Colin","doi":"10.1016/j.ijmultiphaseflow.2024.104991","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.104991","url":null,"abstract":"&lt;div&gt;&lt;p&gt;The development of long-term space thermal management systems has informed research into the influence of gravity on boiling. This work explored the influence of gravity on the hydrodynamics and heat transfer of boiling flow. Experiments were carried out using two test loops each consisting of a 6 mmID transparent cylindrical test section. Upward (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mi&gt;░&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;) and downward (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mi&gt;░&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;) flow boiling experiments were carried out in the laboratory while microgravity (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;) experiments were carried out during a parabolic flight campaign. The results of flow visualisation showed significant influence of gravity on the flow patterns and the influence of gravity was generally limited to mass flux, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;G&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;400&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msup&gt;&lt;mi&gt;s&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and/or vapor quality, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;0.35&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. In all three gravity conditions, the measured heat transfer coefficient was influenced by heat flux, mass flux and/or vapor quality. For liquid Reynolds number, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;msub&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mrow&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;2000&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mrow&gt;&lt;mi&gt;G&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;150&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msup&gt;&lt;mi&gt;s&lt;/mi&gt;&lt;/mrow&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and boiling number &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;0.002&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; the measured heat transfer coefficient was highest in &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; flow and lowest in &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; flow but becomes comparable at &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;mo&gt;&gt;&lt;/mo&gt;&lt;mn&gt;0.002&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. A correlation for predicting microgravity heat transfer coefficient was proposed in this work and the proposed correlation predicted 100 % of the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; data in the current work within &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;20&lt;/mn&gt;&lt;mo&gt;%&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, predicted nearly 100 % of the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; data of &lt;span&gt;&lt;span&gt;Ohta et al. (2013)&lt;/span&gt;&lt;/span&gt; within &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;30&lt;/mn&gt;&lt;mo&gt;%&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and around 85 % of the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; data of &lt;span&gt;&lt;span&gt;Narcy (2014)&lt;/span&gt;&lt;/span&gt; within -20 % to +50 %. A correlation for predicting the gravity dependent regime as it relates to heat transfer coefficient in &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 104991"},"PeriodicalIF":3.6,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0301932224002684/pdfft?md5=495272ac2b385d10ddf92c05eb0a8c29&pid=1-s2.0-S0301932224002684-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142168361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Universal law for identifying the singing vortex","authors":"Zhaohui Qian ,&nbsp;Huan Han ,&nbsp;Yongshun Zeng ,&nbsp;Xiaoxing Peng ,&nbsp;Xianwu Luo","doi":"10.1016/j.ijmultiphaseflow.2024.104993","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.104993","url":null,"abstract":"<div><p>The discrete tone radiated from a cavitating tip vortex, named as ‘vortex singing’, has remained a mystery for over thirty years. In this study, based on the dispersion relation of cavity interfacial waves, the vortex singing is proved to be generated by breathing mode waves propagating from downstream to the hydrofoil tip, solely determined by the mean cavity radius (<em>r_c</em>), the cavitation number (<em>σ</em>) and the desinent cavitation number (<em>σ_d</em>). Then we have identified three types of vortex singing, the universal law, such as the dimensionless singing frequency for each type (<em>ῶ</em> = 2<em>πfr_c</em>/<em>U</em>_∞ = 0.312, 0.037 and 0.926, <em>f</em> is frequency and <em>U</em>_∞ denotes the incoming velocity) and the wavenumber for one typical type (<em>κ</em> = 2<em>πr_c</em> /<em>λ</em> = 0.361, <em>λ</em> represents the wavelength) have been first derived and validated. Furthermore, the minimum cavitation number and desinent cavitation number required for detecting each type of vortex singing are given theoretically. Importantly, we have illustrated a long-standing perplexity: why such a whistler can appear only within a narrow range of frequency, wavelength as well as the cavitation number.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 104993"},"PeriodicalIF":3.6,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}