Theoretical and Computational Fluid Dynamics最新文献_第6页

Inverted stochastic lattice Boltzmann-Lagrangian model for identifying indoor particulate pollutant sources 识别室内颗粒物污染源的反演随机格子Boltzmann拉格朗日模型

IF 3.4 3区工程技术

Theoretical and Computational Fluid Dynamics Pub Date : 2023-10-15 DOI: 10.1007/s00162-023-00675-w

Jinghong Qin

引用次数: 0

Network-theoretic modeling of fluid–structure interactions 流体-结构相互作用的网络理论建模

IF 3.4 3区工程技术

Theoretical and Computational Fluid Dynamics Pub Date : 2023-10-10 DOI: 10.1007/s00162-023-00673-y

Aditya G. Nair, Samuel B. Douglass, Nitish Arya

{"title":"Network-theoretic modeling of fluid–structure interactions","authors":"Aditya G. Nair, Samuel B. Douglass, Nitish Arya","doi":"10.1007/s00162-023-00673-y","DOIUrl":"10.1007/s00162-023-00673-y","url":null,"abstract":"The coupling interactions between deformable structures and unsteady fluid flows occur across a wide range of spatial and temporal scales in many engineering applications. These fluid–structure interactions (FSI) pose significant challenges in accurately predicting flow physics. In the present work, two multi-layer network approaches are proposed that characterize the interactions between the fluid and structural layers for an incompressible laminar flow over a two-dimensional compliant flat plate at a 35(^{circ }) angle of attack. In the first approach, the network nodes are formed by wake vortices and bound vortexlets, and the edges of the network are defined by the induced velocity between these elements. In the second approach, coherent structures (fluid modes), contributing to the kinetic energy of the flow, and structural modes, contributing to the kinetic energy of the compliant structure, constitute the network nodes. The energy transfers between the modes are extracted using a perturbation approach. Furthermore, the network structure of the FSI system is simplified using the community detection algorithm in the vortical approach and by selecting dominant modes in the modal approach. Network measures are used to reveal the temporal behavior of the individual nodes within the simplified FSI system. Predictive models are then built using both data-driven and physics-based methods. Overall, this work sets the foundation for network-theoretic reduced-order modeling of fluid–structure interactions, generalizable to other multi-physics systems.","PeriodicalId":795,"journal":{"name":"Theoretical and Computational Fluid Dynamics","volume":"37 6","pages":"707 - 723"},"PeriodicalIF":3.4,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71909715","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}

引用次数: 0

Aerodynamic and aeroacoustic performance of a pitching foil with trailing edge serrations at a high Reynolds number 带后缘锯齿的俯仰箔在高雷诺数下的气动和气声性能

IF 2.2 3区工程技术

Theoretical and Computational Fluid Dynamics Pub Date : 2023-10-09 DOI: 10.1007/s00162-023-00677-8

Xueyu Ji, Li Wang, Sridhar Ravi, John Young, Joseph C. S. Lai, Fang-Bao Tian

{"title":"Aerodynamic and aeroacoustic performance of a pitching foil with trailing edge serrations at a high Reynolds number","authors":"Xueyu Ji, Li Wang, Sridhar Ravi, John Young, Joseph C. S. Lai, Fang-Bao Tian","doi":"10.1007/s00162-023-00677-8","DOIUrl":"10.1007/s00162-023-00677-8","url":null,"abstract":"The aerodynamic and aeroacoustic performance of a low-aspect-ratio ((hbox {AR}=0.2)) pitching foil during dynamic stall are investigated numerically with focus on the effects of trailing edge serrations. A hybrid method coupling an immersed boundary method for incompressible flows with the Ffowcs Williams–Hawkings acoustic analogy is employed. Large eddy simulation and turbulent boundary layer equation wall model are also employed to capture the turbulent effects. A modified NACA0012 foil with a rectangular trailing edge flap attached to the trailing edge (baseline case) undergoing pitching motion is considered. Trailing edge serrations are applied to the trailing edge flap and their effects on the aerodynamic and aeroacoustic performance of the oscillating airfoil are considered by varying the wave amplitude ((2h^*= 0.05, 0.1), and 0.2) at a Reynolds number of 100,000 and a Mach number of 0.05. It is found that the reduction of the sound pressure level at the dimensionless frequency band (St_{b}in [1.25,4]) can be over 4 dB with the presence of the trailing edge serrations ((2h^*=0.1)), while the aerodynamic performance and its fluctuations are not significantly altered except a reduction around 10% in the negative moment coefficient and it fluctuations. This is due to the reduction of the average spanwise coherence function and the average surface pressure with respect to that of the baseline case, suggesting the reduction of the spanwise coherence and the noise source may result in the noise reduction. Analysis of the topology of the near wake coherent structure for (2h^*=0.1) reveals that the alignment of the streamwise-oriented vortex with the serration edge may reduce the surface pressure fluctuation.","PeriodicalId":795,"journal":{"name":"Theoretical and Computational Fluid Dynamics","volume":"38 6","pages":"825 - 844"},"PeriodicalIF":2.2,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00162-023-00677-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135093791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Galerkin spectral estimation of vortex-dominated wake flows 旋涡主导尾流的伽辽金谱估计

IF 2.2 3区工程技术

Theoretical and Computational Fluid Dynamics Pub Date : 2023-08-07 DOI: 10.1007/s00162-023-00670-1

Katherine J. Asztalos, Abdulrahman Almashjary, Scott T. M. Dawson

{"title":"Galerkin spectral estimation of vortex-dominated wake flows","authors":"Katherine J. Asztalos, Abdulrahman Almashjary, Scott T. M. Dawson","doi":"10.1007/s00162-023-00670-1","DOIUrl":"10.1007/s00162-023-00670-1","url":null,"abstract":"We propose a technique for performing spectral (in time) analysis of spatially-resolved flowfield data, without needing any temporal resolution or information. This is achieved by combining projection-based reduced-order modeling with spectral proper orthogonal decomposition. In this method, space-only proper orthogonal decomposition is first performed on velocity data to identify a subspace onto which the known equations of motion are projected, following standard Galerkin projection techniques. The resulting reduced-order model is then utilized to generate time-resolved trajectories of data. Spectral proper orthogonal decomposition (SPOD) is then applied to this model-generated data to obtain a prediction of the spectral content of the system, while predicted SPOD modes can be obtained by lifting back to the original velocity field domain. This method is first demonstrated on a forced, randomly generated linear system, before being applied to study and reconstruct the spectral content of two-dimensional flow over two collinear flat plates perpendicular to an oncoming flow. At the range of Reynolds numbers considered, this configuration features an unsteady wake characterized by the formation and interaction of vortical structures in the wake. Depending on the Reynolds number, the wake can be periodic or feature broadband behavior, making it an insightful test case to assess the performance of the proposed method. In particular, we show that this method can accurately recover the spectral content of periodic, quasi-periodic, and broadband flows without utilizing any temporal information in the original data. To emphasize that temporal resolution is not required, we show that the predictive accuracy of the proposed method is robust to using temporally-subsampled data.","PeriodicalId":795,"journal":{"name":"Theoretical and Computational Fluid Dynamics","volume":"38 6","pages":"801 - 823"},"PeriodicalIF":2.2,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44195277","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}

引用次数: 0

Shock stand-off distances over sharp wedges for thermally non-equilibrium dissociating nitrogen flows 热非平衡解离氮流的尖锐楔形激波隔离距离

IF 3.4 3区工程技术

Theoretical and Computational Fluid Dynamics Pub Date : 2023-07-29 DOI: 10.1007/s00162-023-00669-8

U. Yildiz, D. Vatansever, B. Celik

{"title":"Shock stand-off distances over sharp wedges for thermally non-equilibrium dissociating nitrogen flows","authors":"U. Yildiz, D. Vatansever, B. Celik","doi":"10.1007/s00162-023-00669-8","DOIUrl":"10.1007/s00162-023-00669-8","url":null,"abstract":"In this study, shock stand-off distances for thermally and chemically non-equilibrium flows of nitrogen over wedges are computationally investigated via a hypersonic computational fluid dynamics solver, hyperReactingFoam by spanning a parameter space that consists of ranges of Mach number, 4–10, specific heat ratio, 1.40–1.61 and wedge angles, 60(^circ )–90(^circ ). Then, the space is reduced into the parameters of inverse density ratio across the shock and dimensionless wedge angle which will be used as variables for quadratic functions that represent shock stand-off distances. Besides the functions of shock stand-off distances, detached shock profiles of computationally modeled flows are represented by parabolic equations. The flows are observed to be chemically frozen for Mach number ranges of 4–5 regardless of the specific heat ratio value of the nitrogen mixture. Our results show that the shock stand-off distance decreases as Mach number is increased from 4 to 7, if the wedge angle and free-stream specific heat ratio are kept the same. On the other hand, if Mach number is increased beyond 7, the shock stand-off distance starts to extend due to the dissociation of nitrogen molecules behind the shock wave. At Mach 10, nitrogen completely dissociates over 90(^circ ) wedge for all specific heat ratios considered in the present study. Increased leading edge angle of the wedge or specific heat ratio of free-stream yields longer shock stand-off distance.","PeriodicalId":795,"journal":{"name":"Theoretical and Computational Fluid Dynamics","volume":"37 6","pages":"799 - 821"},"PeriodicalIF":3.4,"publicationDate":"2023-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44093250","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}

引用次数: 0

Linear stability analysis of compressible pipe flow 可压缩管道流动的线性稳定性分析

IF 3.4 3区工程技术

Theoretical and Computational Fluid Dynamics Pub Date : 2023-07-24 DOI: 10.1007/s00162-023-00672-z

Mandeep Deka, Gaurav Tomar, Viswanathan Kumaran

{"title":"Linear stability analysis of compressible pipe flow","authors":"Mandeep Deka, Gaurav Tomar, Viswanathan Kumaran","doi":"10.1007/s00162-023-00672-z","DOIUrl":"10.1007/s00162-023-00672-z","url":null,"abstract":"The linear stability of a compressible flow in a pipe is examined using a modal analysis. A steady fully developed flow of a calorifically perfect gas, driven by a constant body acceleration, in a pipe of circular cross section is perturbed by small-amplitude normal modes and the temporal stability of the system is studied. In contrast to the incompressible pipe flow that is linearly stable for all modal perturbations, the compressible flow is unstable at finite Mach numbers due to modes that do not have a counterpart in the incompressible limit. We obtain these higher modes for a pipe flow through numerical solution of the stability equations. The higher modes are distinguished into an “odd” and an “even” family based on the variation of their wave-speeds with wave-number. The classical theorems of stability are extended to cylindrical coordinates and are used to obtain the critical Mach numbers below which the higher modes are always stable. The critical Reynolds number is calculated as a function of Mach number for the even family of modes, which are the least stable at finite Mach numbers. The numerical solution of the stability equations in the high Reynolds number limit demonstrates that viscosity is essential for destabilizing the even family of modes. An asymptotic analysis is carried out at high Reynolds numbers to obtain the scalings, and solutions for the eigenvalues in the high Reynolds number limit for the lower and upper branches of the stability curve.","PeriodicalId":795,"journal":{"name":"Theoretical and Computational Fluid Dynamics","volume":"37 5","pages":"589 - 625"},"PeriodicalIF":3.4,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42754893","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}

引用次数: 0

Interaction between depth variation and turbulent diffusion in depth-averaged vorticity equations 深度平均涡度方程中深度变化与湍流扩散的相互作用

IF 3.4 3区工程技术

Theoretical and Computational Fluid Dynamics Pub Date : 2023-07-21 DOI: 10.1007/s00162-023-00665-y

Balázs Sándor, Péter Torma, K. Gábor Szabó, Tamás Kalmár-Nagy

引用次数: 0

Faster flicker of buoyant diffusion flames by weakly rotatory flows 弱旋转流引起的浮力扩散火焰的更快闪烁

IF 3.4 3区工程技术

Theoretical and Computational Fluid Dynamics Pub Date : 2023-07-18 DOI: 10.1007/s00162-023-00671-0

Tao Yang, Peng Zhang

{"title":"Faster flicker of buoyant diffusion flames by weakly rotatory flows","authors":"Tao Yang, Peng Zhang","doi":"10.1007/s00162-023-00671-0","DOIUrl":"10.1007/s00162-023-00671-0","url":null,"abstract":"Flickering buoyant diffusion methane flames in weakly rotatory flows were computationally and theoretically investigated. The prominent computational finding is that the flicker frequency nonlinearly increases with the nondimensional rotational intensity R (up to 0.24), which is proportional to the nondimensional circumferential circulation. This finding is consistent with the previous experimental observations that rotatory flows enhance flame flicker to a certain extent. Based on the vortex-dynamical understanding of flickering flames that the flame flicker is caused by the periodic shedding of buoyancy-induced toroidal vortices, a scaling theory is formulated for flickering buoyant diffusion flames in weakly rotatory flows. The theory predicts that the increase of flicker frequency f obeys the scaling relation (left( f-f_{0} right) propto R^{2}), which agrees very well with the present computational results. In physics, the external rotatory flow enhances the radial pressure gradient around the flame, and the significant baroclinic effect (mathrm {nabla }ptimes mathrm {nabla }rho ) contributes an additional source for the growth of toroidal vortices so that their periodic shedding is faster.","PeriodicalId":795,"journal":{"name":"Theoretical and Computational Fluid Dynamics","volume":"37 6","pages":"781 - 798"},"PeriodicalIF":3.4,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45671843","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}

引用次数: 3

Wind tunnel effects on gust-interaction simulations 风-相互作用模拟中的风洞效应

IF 3.4 3区工程技术

Theoretical and Computational Fluid Dynamics Pub Date : 2023-07-16 DOI: 10.1007/s00162-023-00668-9

Diederik Beckers, Jeff D. Eldredge

{"title":"Wind tunnel effects on gust-interaction simulations","authors":"Diederik Beckers, Jeff D. Eldredge","doi":"10.1007/s00162-023-00668-9","DOIUrl":"10.1007/s00162-023-00668-9","url":null,"abstract":"Large-amplitude flow disturbances, or gusts, can drastically alter the aerodynamic forces on an airfoil and are regularly investigated through wind tunnel (or water tunnel) experiments. The gusts generated in those experiments are often further analyzed using numerical simulations, but usually without fully accounting for the wind tunnel walls or gust generator. The current work investigates the wind tunnel effects on the predicted lift response and flow field using a computational framework that models the viscous flow around the airfoil but treats the tunnel walls and gust generation as inviscid boundary conditions. We apply this model to three examples and compare the predicted gust response with the responses predicted by a free-space viscous model and a classical unsteady aerodynamics model to highlight the wind tunnel effects. We find that the wind tunnel modeling introduces non-negligible effects depending on the airfoil and gust configurations. These effects include the confinement effect of the wind tunnel walls and the triggering of flow separation when it does not occur in the corresponding free-space model. In the last example, we also note that this virtual counterpart of an actual wind tunnel can be paired with experiments through data assimilation to increase the accuracy of the gust response or perform parameter estimation.","PeriodicalId":795,"journal":{"name":"Theoretical and Computational Fluid Dynamics","volume":"37 4","pages":"533 - 548"},"PeriodicalIF":3.4,"publicationDate":"2023-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4651002","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}

引用次数: 0

An Eulerian–Eulerian–Lagrangian modeling of two-phase combustion 两相燃烧的欧拉-欧拉-拉格朗日模型

IF 3.4 3区工程技术

Theoretical and Computational Fluid Dynamics Pub Date : 2023-07-15 DOI: 10.1007/s00162-023-00666-x

L. X. Zhou

{"title":"An Eulerian–Eulerian–Lagrangian modeling of two-phase combustion","authors":"L. X. Zhou","doi":"10.1007/s00162-023-00666-x","DOIUrl":"10.1007/s00162-023-00666-x","url":null,"abstract":"In simulating two-phase combustion, most Reynolds-averaged Navier–Stokes (RANS) simulation and large-eddy simulation (LES) used Eulerian–Lagrangian (E–L) modeling (Eulerian treatment of gas phase and Lagrangian treatment of particles/droplets) which needs much more computational time than the Eulerian–Eulerian (E–E) or two-fluid modeling. However, in the E–E modeling, the problem of how to reduce the computation time for poly-dispersed particles is encountered . To solve this problem, the present author proposed an Eulerian–Eulerian–Lagrangian (E–E–L) modeling of two-phase combustion for both RANS modeling and LES. The E–E–L modeling is an Eulerian treatment of gas phase and a combined Eulerian–Lagrangian treatment of particles/droplets, in which the particle velocity and concentration are solved by Eulerian modeling, and particle temperature and mass change due to reaction are solved by Lagrangian modeling. In this paper, a review is given for an E–E–L modeling of coal combustion, its application in RANS simulation and its possible application in LES. For E–E–L LES, an energy equation model of two-phase sub-grid scale (SGS) stresses accounting for the interaction between two-phase SGS stresses is suggested, and a second-order moment SGS (SOM-SGS) turbulence-chemistry model is adopted to simulate gas-phase reaction in two-phase combustion. These SGS models were separately assessed by comparison with experiments.","PeriodicalId":795,"journal":{"name":"Theoretical and Computational Fluid Dynamics","volume":"37 6","pages":"767 - 780"},"PeriodicalIF":3.4,"publicationDate":"2023-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42789731","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}

引用次数: 0