Journal of Turbulence最新文献_第8页

Investigation on turbulent characteristic of crossflow under suction in a T-junction using Holo-Hilbert spectral analysis 用Holo-Hilbert谱分析研究t型结中吸力作用下横流的湍流特性

IF 1.9 4区工程技术

Journal of Turbulence Pub Date : 2021-12-04 DOI: 10.1080/14685248.2021.2009842

Xuefang Xu, Huaishuang Shao, Ruixiong Li, Mei Lin, Peiming Shi

{"title":"Investigation on turbulent characteristic of crossflow under suction in a T-junction using Holo-Hilbert spectral analysis","authors":"Xuefang Xu, Huaishuang Shao, Ruixiong Li, Mei Lin, Peiming Shi","doi":"10.1080/14685248.2021.2009842","DOIUrl":"https://doi.org/10.1080/14685248.2021.2009842","url":null,"abstract":"To investigate the crossflow of ventilation in high-speed train, a T-junction experimental setup is built and velocity data of crossflow under different conditions and positions are measured. Specifically, the conditions include the different velocities of crossflow and different intensities of suction, and the positions include upstream, mid-centre, and downstream. To give full information of the crossflow characteristics, the Holo-Hilbert spectral analysis (HHSA) method is used to analyse these velocity data. The results show that the components of frequency modulation (FM) and amplitude modulation (AM) can be found in the crossflow suffered from the suction. Furthermore, there exists an obvious difference between the crossflow with and without vanes. The crossflow without vanes has more components of FM modulation and AM modulation with high frequency. The increase of the velocity and velocity ratio both can influence the turbulent characteristics of crossflow, which presents high energy with a higher frequency of AM and FM. The crossflow at the upstream and the downstream has similar components presented in the AM–FM spectrum, while the crossflow at the mid-centre has more high-frequency components. In addition, the turbulent intensity at the mid-centre is inversely proportional to the distance from the suction.","PeriodicalId":49967,"journal":{"name":"Journal of Turbulence","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2021-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41948231","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: 1

Hydrodynamics of flow through a degraded channel bed 流经退化河床的流体动力学

IF 1.9 4区工程技术

Journal of Turbulence Pub Date : 2021-12-02 DOI: 10.1080/14685248.2021.2007256

Mosedul Sarkar, S. Maurya, Partha P. Gopmandal, Sankar Sarkar

{"title":"Hydrodynamics of flow through a degraded channel bed","authors":"Mosedul Sarkar, S. Maurya, Partha P. Gopmandal, Sankar Sarkar","doi":"10.1080/14685248.2021.2007256","DOIUrl":"https://doi.org/10.1080/14685248.2021.2007256","url":null,"abstract":"This article presents experimental results of turbulent flow measured in a bimodal degraded channel bed consisting of sand-gravel mixture. Sand and gravel of uniform sizes 0.25 and 3.5 mm were mixed in the same proportions (by weight) to create a bimodal sedimentary bed. A three-dimensional Vectrino velocimeter was employed to collect three-dimensional velocities over bimodal degraded bed under equilibrium condition. The streamwise velocity, Reynolds stresses, turbulent kinetic energy (TKE), and TKE fluxes profiles were compared with the literature. However, the advancement of the existing knowledge was done by exploring the laws of turbulence. To this end, the velocity structure function method was applied. Second and third-order streamwise velocity structure functions followed by mixed third-order velocity structure functions revealed the existence of inertial subrange. The TKE dissipation rate was estimated using Kolmogorov’s and Monin–Yaglom’s scaling laws of turbulence. The anisotropy analysis indicated anisotropic turbulence in the near-bed, whereas above the initial bed-level, the anisotropy tends to follow three-dimensional isotropy. The present study notably enhances the understanding of turbulent flow through a degraded bed by demonstrating the legitimacy of laws of turbulence at different locations over the bed and providing a comprehensible acquaintance in TKE budget and Reynolds stress anisotropy.","PeriodicalId":49967,"journal":{"name":"Journal of Turbulence","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41301324","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: 4

Build up of yield stress fluids via chaotic emulsification 通过混沌乳化形成屈服应力流体

IF 1.9 4区工程技术

Journal of Turbulence Pub Date : 2021-11-24 DOI: 10.1080/14685248.2022.2067333

Ivan Girotto, R. Benzi, G. Di Staso, A. Scagliarini, S. Schifano, F. Toschi

引用次数: 5

A multispecies turbulence model for the mixing and de-mixing of miscible fluids 混相流体混合与脱混的多组分湍流模型

IF 1.9 4区工程技术

Journal of Turbulence Pub Date : 2021-10-15 DOI: 10.1080/14685248.2021.1983180

N. Braun, R. Gore

引用次数: 5

Metric inertia for eddy densities of nonlocal matter-space 非局部物质空间涡密度的度量惯性

IF 1.9 4区工程技术

Journal of Turbulence Pub Date : 2021-10-03 DOI: 10.1080/14685248.2021.1953698

I. Bulyzhenkov

{"title":"Metric inertia for eddy densities of nonlocal matter-space","authors":"I. Bulyzhenkov","doi":"10.1080/14685248.2021.1953698","DOIUrl":"https://doi.org/10.1080/14685248.2021.1953698","url":null,"abstract":"ABSTRACT Monistic thermomechanics of eddy mater-space with metric stresses of Maxwellian type and inelastic metric waves can be developed for purely kinetic densities of the nonlocal mass-energy integral. Pseudo-Riemannian 4-geometry uses locally warped time to preserve the Euclidean sublight transport of nonlocally correlated densities with instantaneous metric connections and coherent conservation of local 4-currents everywhere. The kinematic viscosity of geometrised energy-momentum densities and their geodesic self-pushes by correlated metric stresses quantitatively clarify the adaptive all-unity of continuous kinetic energy, including material ether or variable rest-energy. The metric self-organisation of matter-space+time implies a nonlocal feedback of correlated eddy densities and their tensor response to the vector density of external forces. Such tensor inertial responses of correlated metric stresses reveal the nonlocal nature of turbulence and predict adaptive auto-modes or thermal waves of Euclidean material space due to the modified geodesic equation with viscose autowaves and the inverse Cavendish constant. The proposed nonlocal alternative to Euler/Navier-Stokes hydrodynamics can distinguish between Cartesian and Newtonian worldviews in conceptual laboratory probes of new macroscopic mechanics for metric self-organisations of thermokinetic energies of viscose material space without negative gravitational energies.","PeriodicalId":49967,"journal":{"name":"Journal of Turbulence","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2021-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44182546","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: 2

Large-eddy simulations of the flow on an aerofoil with leading-edge imperfections 具有前缘缺陷的翼型流动的大涡模拟

IF 1.9 4区工程技术

Journal of Turbulence Pub Date : 2021-09-12 DOI: 10.1080/14685248.2021.1973015

Vishal Kumar, U. Piomelli, O. Lehmkuhl

{"title":"Large-eddy simulations of the flow on an aerofoil with leading-edge imperfections","authors":"Vishal Kumar, U. Piomelli, O. Lehmkuhl","doi":"10.1080/14685248.2021.1973015","DOIUrl":"https://doi.org/10.1080/14685248.2021.1973015","url":null,"abstract":"ABSTRACT We performed large-eddy simulations of the flow over an aerofoil to understand the effects of leading-edge roughness designed to mimic ice accretion. The roughness elements protrude outside the boundary layer, which, near the leading edge, is very thin; thus, the configuration does not represent a classical rough-wall boundary layer, but rather the flow over macroscopic obstacles. A grid convergence study is conducted and results are validated by comparison to numerical and experimental studies in the literature. The main effect of the obstacles is to accelerate transition to turbulence. Significant variations in structure generation are observed for different roughness shapes. The three-dimensionality of the irregularities has a strong impact on the flow: it creates alternating regions of high-speed (‘peaks’) and low-speed (‘valleys’) regions, a phenomenon termed ‘channelling’. The valley regions resemble a decelerating boundary layer: they exhibit considerable wake and higher levels of Reynolds stresses. The peak regions, on the other hand, are more similar to an accelerating one. Implications of the channelling phenomenon on turbulence modelling are discussed.","PeriodicalId":49967,"journal":{"name":"Journal of Turbulence","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2021-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46085618","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: 1

Turbulent drag reduction over liquid-infused textured surfaces: effect of the interface dynamics 注入液体的纹理表面上的湍流减阻：界面动力学的影响

IF 1.9 4区工程技术

Journal of Turbulence Pub Date : 2021-09-11 DOI: 10.1080/14685248.2021.1973013

M. Bernardini, E. J. García Cartagena, A. Mohammadi, A. Smits, S. Leonardi

{"title":"Turbulent drag reduction over liquid-infused textured surfaces: effect of the interface dynamics","authors":"M. Bernardini, E. J. García Cartagena, A. Mohammadi, A. Smits, S. Leonardi","doi":"10.1080/14685248.2021.1973013","DOIUrl":"https://doi.org/10.1080/14685248.2021.1973013","url":null,"abstract":"Direct numerical simulations of a turbulent channel with liquid infused surfaces made of longitudinal micro-ridges have been performed to study the effect of texture geometry and interface deformation. The flow conditions consider a viscosity ratio , several values of the micro-ridge pitch and two different Weber numbers, We = 0 and We = 50. The performance is analyzed in terms of drag reduction (DR) with respect to an equivalent smooth channel, and the results compared with those available for super-hydrophobic surfaces (SHS). It is found that, due to the relatively high viscosity of the liquid locked in the substrate, the drag reduction offered by LIS is substantially lower than the corresponding SHS. When reported in terms of the streamwise slip length normalized in wall units, the amount of DR obtained by LIS in the ideal case of flat interface collapses on the SHS data. The interface dynamics has a detrimental effect on the performance, that becomes particularly severe when the pitch increases. The degradation of DR is well parametrized by the log-law shift of the velocity profile, that is found to be proportional to the difference between the virtual origin of the mean flow and that experienced by the overlying turbulence.","PeriodicalId":49967,"journal":{"name":"Journal of Turbulence","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2021-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42928764","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

Characteristics of wall-shear stress fluctuations in shock wave and turbulent boundary layer interaction 激波与湍流边界层相互作用中壁面剪切应力波动特征

IF 1.9 4区工程技术

Journal of Turbulence Pub Date : 2021-09-11 DOI: 10.1080/14685248.2021.1974466

Fulin Tong, J. Duan, Xinliang Li

{"title":"Characteristics of wall-shear stress fluctuations in shock wave and turbulent boundary layer interaction","authors":"Fulin Tong, J. Duan, Xinliang Li","doi":"10.1080/14685248.2021.1974466","DOIUrl":"https://doi.org/10.1080/14685248.2021.1974466","url":null,"abstract":"The wall-shear stress (WSS) fluctuations in the interaction of an oblique shock wave with a flat-plate turbulent boundary layer are investigated by means of direct numerical simulation (DNS) at Mach 2.25. The numerical results agree very well with previous experiments and DNS data in terms of turbulence statistics, wall pressure, and skin friction. The fluctuating WSS characteristics, including probability density function (PDF), frequency spectrum, space–time correlation, and convection velocity, are analysed systematically. It is found that the positively skewed PDF shape of the streamwise WSS fluctuations is significantly changed due to the presence of a separation bubble, while the PDF shape of the spanwise component is slightly affected, exhibiting a symmetric behaviour across the interaction. The weighted power-spectrum density map indicates that the low-frequency unsteadiness associated with the separated shock - exhibits little influence on the spectrum for either component, and no enhancement of the low-frequency energy is observed. A significant reduction in the spatial extent of the two-point correlation is observed, causing spanwise elongated coherence for the streamwise WSS fluctuations in the separation region. Moreover, the elliptic behaviour of the space–time correlations is essentially preserved throughout the interaction, and this is accompanied by a sudden reduction of the convection velocity in the separation bubble.","PeriodicalId":49967,"journal":{"name":"Journal of Turbulence","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2021-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47144787","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: 1

A simplified model for drag evaluation of a streamlined body with leading-edge damage 具有前缘损伤的流线型机身阻力评估的简化模型

IF 1.9 4区工程技术

Journal of Turbulence Pub Date : 2021-09-11 DOI: 10.1080/14685248.2021.1973012

Haoliang Yu, U. Ciri, A. Malik, S. Leonardi

引用次数: 0

A double-averaged Navier-Stokes k – ω turbulence model for wall flows over rough surfaces with heat transfer 具有传热的粗糙表面壁流的双平均Navier-Stokes k–ω湍流模型

IF 1.9 4区工程技术

Journal of Turbulence Pub Date : 2021-09-11 DOI: 10.1080/14685248.2021.1973014

F. Chedevergne

引用次数: 4