Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics最新文献

{"title":"A High-Order Flux Reconstruction Method for 2-D Vorticity Transport","authors":"A. Gharakhani","doi":"10.1115/fedsm2021-63196","DOIUrl":"https://doi.org/10.1115/fedsm2021-63196","url":null,"abstract":"A compact high-order finite difference method on unstructured meshes is developed for discretization of the unsteady vorticity transport equations (VTE) for 2-D incompressible flow. The algorithm is based on the Flux Reconstruction Method of Huynh [1, 2], extended to evaluate a Poisson equation for the streamfunction to enforce the kinematic relationship between the velocity and vorticity fields while satisfying the continuity equation. Unlike other finite difference methods for the VTE, where the wall vorticity is approximated by finite differencing the second wall-normal derivative of the streamfunction, the new method applies a Neumann boundary condition for the diffusion of vorticity such that it cancels the slip velocity resulting from the solution of the Poisson equation for the streamfunction. This yields a wall vorticity with order of accuracy consistent with that of the overall solution. In this paper, the high-order VTE solver is formulated and results presented to demonstrate the accuracy and convergence rate of the Poisson solution, as well as the VTE solver using benchmark problems of 2-D flow in lid-driven cavity and backward facing step channel at various Reynolds numbers.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117063902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Investigating of Oscillatory Flow and Heat Transfer Through Stirling Regenerator","authors":"Houda Hachem, R. Gheith, F. Aloui","doi":"10.1115/fedsm2021-65624","DOIUrl":"https://doi.org/10.1115/fedsm2021-65624","url":null,"abstract":"\u0000 By developing our proper CFD code under Fortran, the performances of a Stirling engine are studied in unsteady laminar regime and closely linked to the properties of its regenerator. However, it is responsible about the maximum part of losses in the Stirling engine. These losses depend on geometric and physical properties of the material constituting the regenerator. Thus, finding the suitable regenerator material that generates the greatest heat exchange and the lowest pressure drop is a good solution to reduce sources of irreversibility and ameliorate the global performances of the Stirling engine. The aim of this paper is to describe oxillatory flow and heat transfer inside porous regenerator materials and to determine the most suitable regenerator material. Brinkman-Forchheimer-Lapwood extended Darcy model is assumed to simulate momentum transfer within the porous regenerator. And the oscillatory flow is described by the Navier-Stockes compressible equations. The local thermal equilibrium of the gas and the matrix is taken into account for the modelling of the porous regenerator. The governing equations with the appropriate boundary conditions are solved by the control volume based finite element method (CVFEM). A numerical code on the software Fortran is elaborated to evaluate flow and heat transfer characteristics inside regenerator. Results showed that the fluid flow and heat transfer between the compression and expansion phases were varied significantly. It was shown that the superior comprehensive performance of the regenerator makes it possible to improve the performance of Stirling engines.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115060179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Hybrid High-Order Vorticity-Based Eulerian and Lagrangian Vortex Particle Method, the 2-D Case","authors":"Mark J. Stock, A. Gharakhani","doi":"10.1115/fedsm2021-65637","DOIUrl":"https://doi.org/10.1115/fedsm2021-65637","url":null,"abstract":"\u0000 Hybrid Lagrangian-Eulerian solvers combine the convective and compactness advantages of vortex methods with the spatial anisotropy and boundary-resolving advantages of Eulerian methods to create flexible solvers capable of adequately capturing thin boundary layers while still maintaining wake vortex coherency for unsteady incompressible flow in complex geometries. The present paper details a new hybrid method which combines, in one open-source package, a novel, compact, high-order Eulerian scheme for vorticity transport to predict the flow in the near-boundary region with a grid-free, unremeshed, Lagrangian Vortex Particle Method (LVPM) for the off-boundary vorticity-containing region. This paper focuses on the hybridization of the two methods and demonstrates its effectiveness on two canonical benchmarks: flow in 2-D lid-driven cavity at Re = 1,000 and impulsively started flow over a circular cylinder at Re = 9,500. In each case, the hybrid method improves upon a pure LVPM and uses far fewer cells than a purely Eulerian scheme. In addition, the size of the associated Eulerian region is greatly reduced compared to previous hybrid methods.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"238 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122689928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aerodynamic Performance Evaluation of a Skydio UAV via CFD As a Platform for Bridge Girder Inspection: Phase 1 Study","authors":"Rodward L. Hewlin, Elizabeth Smith, Tara L. Cavalline, A. Karimoddini","doi":"10.1115/fedsm2021-65996","DOIUrl":"https://doi.org/10.1115/fedsm2021-65996","url":null,"abstract":"\u0000 The goal of the proposed work was to analyze the aerodynamic performance of a Skydio 6 unmanned aerial vehicle (UAV) as a supplementary tool for bridge girder inspections. The use of UAVs has become more attractive due to their ability to gather critical information in less time and at a lower cost when compared to traditional bridge girder inspection techniques. In pursuit of this goal, the present work presents aerodynamic performance evaluation results via computational fluid dynamics (CFD) of a Skydio 2 UAV for bridge girder inspection. The study is implemented using the commercially available CFD solver, ANSYS FLUENT (v. 19). The evaluation study utilized an unstructured tetrahedron meshing technique throughout the numerical analysis, with a standard k-epsilon turbulence model. The Multiple Reference Frame (MRF) model was also used to model the rotation of the propellers toward their local reference frame at 6000 revolutions per minute (RPM). This paper presents the numerical modeling methodology as well as a discussion of parametric results. The parametric results presented show reliable moment coefficient and thrust making the Skydio 2 UAV suitable for bridge inspection.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125394195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid-Structure Interaction Simulations of Parachute Deployment and Inflation","authors":"Liwu Wang, Mingzhang Tang, Yu Liu, Sijun Zhang","doi":"10.1115/fedsm2021-65583","DOIUrl":"https://doi.org/10.1115/fedsm2021-65583","url":null,"abstract":"\u0000 The numerical simulation of the parachute deployment/inflation process involves fluid structure interaction problems, the inherent complexities in the fluid structure interaction have been posing several computational challenges. In this paper a high fidelity Eulerian computational approach is proposed for the simulation of parachute deployment/inflation. Unlike the arbitrary Eulerian Lagrangian (ALE) method widely employed in this area, the Eulerian computational approach is established on three computational techniques: computational fluid dynamics, computational structure dynamics and computational moving boundary. A set of stationary, non-deforming Cartesian grids is adopted in our computational fluid dynamics, our computational structure dynamics is enhanced by non-linear finite element method and membrane wrinkling algorithm, instead of conventional computational mesh dynamics, an immersed boundary method is employed to avoid insurmountable poor grid quality brought in by moving mesh approaches. To validate the proposed numerical approach the deployment/inflation of C-9 parachute is simulated using our approach and the results show similar characteristics compared with experimental results and previous literature. The computed results have demonstrated the proposed method to be a useful tool for analyzing dynamic parachute deployment and subsequent inflation.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126044320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep Learning Techniques for Effective Prediction of Aerodynamic Properties of Elliptical Bluff Bodies","authors":"W. M. U. Weerasekara, H. M. C. D. B. Gunarathna, W. A. K. P. Wanigasooriya, T. P. Miyanawala","doi":"10.1115/fedsm2021-66265","DOIUrl":"https://doi.org/10.1115/fedsm2021-66265","url":null,"abstract":"Predicting aerodynamic forces on bluff bodies remains to be a challenging task due to the unpredictable flow behavior, specifically at higher Reynolds numbers. Experimental approaches to determine aerodynamic coefficients could be costly and time consuming. In the meantime, use of numerical techniques could also require a considerable computational cost and time depending on complexity of the flow behavior. The research focusses on developing an effective deep learning technique to predict aerodynamic force coefficients acting on elliptical bluff bodies for a given aspect ratio and given flow condition. Collecting data for drag and lift coefficients of several aspect ratios for flow conditions starting from onset of vortex shredding to verge of subcritical region is conducted by an accurate full order model. The specified region will provide a transient flow behavior and thus lift coefficient will be represented in terms of root mean square value and drag coefficient in terms of a mean value. With variations in flow behavior and vortex shredding frequencies, it requires to select an appropriate turbulence model, optimum discretization of fluid domain and time step to obtain an accurate result. Flow simulations are conducted primarily using Unsteady Reynolds Averaged Navier-Stokes Equations (URANS) model and Detached Eddy Simulations (DES) model. Effectiveness in using different turbulence models for specified flow regimes are also explored in comparison to available experimental results. At lower Reynolds numbers, aerodynamic force coefficients for a specified body will only depend on Reynolds number. But after a certain specific Reynolds number, aerodynamic forces are dependent on the Mach number in addition to Reynolds number. Therefore, for higher Reynolds numbers, aerodynamic force coefficients are recorded for multiple Mach numbers with same Reynolds number and will be fed to the neural network. With the development of the machine learning and neural network modelling, many of the fields have nourished and created effective and efficient technologies to ease complex functions and activities. Our goal is to ease the complexity in the computational fluid dynamic field with a deep neural network tool created to predict drag and lift coefficient of elliptical bluff bodies for a given aspect ratio with an acceptable accuracy level. Researchers have developed deep neural network tools to predict various flow conditions and have succeeded with sufficient accuracy and a satisfying reduction of computational cost. In our proposed deep learning neural network, we have chosen to model the network with inputs as the geometry setup and the flow conditions with validated drag and lift coefficients. The model will extract the necessary flow features into filters with the convolution operation performed on the inputs. Our main directive is to create a deep learned neural network tool to predict the target values within an acceptable range of accuracy while ","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126074889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solution-Responsive Particle Size Adaptivity in Lagrangian Vortex Particle Methods","authors":"Mark J. Stock, A. Gharakhani","doi":"10.1115/fedsm2021-65621","DOIUrl":"https://doi.org/10.1115/fedsm2021-65621","url":null,"abstract":"\u0000 In order to minimize the computational resources necessary for a given level of accuracy in a Lagrangian Vortex Particle Method, a novel particle core size adaptivity scheme has been created. The method adapts locally to the solution while preventing large particle size gradients, and optionally adapts globally to focus effort on important regions. It is implemented in the diffusion solver, which uses the Vorticity Redistribution Method, by allowing and accounting for variations in the core radius of participating particles. We demonstrate the effectiveness of this new method on the diffusion of a δ-function and impulsively started flow over a circular cylinder at Re = 9,500. In each case, the adaptive method provides solutions with marginal loss of accuracy but with substantially fewer computational elements.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132146777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational Analysis of Non-Premixed Combustion in a Scramjet Combustor With a Wedge Shaped Strut Injector","authors":"Sajal Katare, N. Yadav","doi":"10.1115/fedsm2021-65951","DOIUrl":"https://doi.org/10.1115/fedsm2021-65951","url":null,"abstract":"\u0000 This paper focuses the computational study of non-premixed combustion in a scramjet combustor. The wedge shaped strut injector was used in the combustion process. In order to investigate the flame holding mechanism of the wedge shaped strut in supersonic flow, the two-dimensional coupled implicit RANS equations, the standard k-ε turbulence model and the finite-rate/eddy-dissipation reaction model are introduced to simulate the flow field of the hydrogen fueled scramjet combustor with a strut flame holder under different conditions. The static pressure of the case under the engine ignition condition is much higher than that of the case under the cold flow condition. The reflection of shock waves improves the mixing of hydrogen with the stream of inlet air and thus increases combustion efficiency. The mass flow rate of air is optimized for the best performance of engine.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126103523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Simulation of a Canadian Well With Several Circumferential Rows of Internal Vortex Generators","authors":"N. Kharoua, H. Semmari, Houssem Korichi, M. Haroun","doi":"10.1115/fedsm2021-65814","DOIUrl":"https://doi.org/10.1115/fedsm2021-65814","url":null,"abstract":"\u0000 Canadian Wells exploit the quasi-stable underground temperature throughout the year for cooling and heating applications. This type of heat exchangers is used in residential buildings, agriculture and industry. Implementing Vortex Generators (VGs) is intended to disturb the thermal and dynamic boundary layers developing in the near-wall regions leading to the increase of the heat transfer coefficient.\u0000 The present work investigates the positive effects of a sequence of several rows of VGs. The commercial code ANSYS FLUENT was used to perform numerical simulations mimicking the variation of the seasonal operational conditions occurring within one year. The ambient conditions were considered for the city of Constantine located in the east of Algeria at an altitude of 600m over the sea level. Sinusoidal functions of time and depth, were used for the yearly variations of the ground and air temperatures. Parallelepiped VGs were considered in this study. The Reynolds number was in the range Re = 14975–42789.\u0000 The results illustrated a contrasting effect of the Reynolds number on the heat transfer coefficient and the temperature difference between the inlet and outlet of the Canadian Well. In terms of number of VGs rows, the beneficial heat transfer effects were observed till the fifth row only.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125020535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aerodynamic Performance of Design for a CO2 Dragster","authors":"Brandon Paez, Arturo Rodríguez, Nicholas Dudu, Jose Terrazas, Richard Adansi, V. Kotteda, Julio C. Aguilar, Vinod Kumar","doi":"10.1115/fedsm2021-65793","DOIUrl":"https://doi.org/10.1115/fedsm2021-65793","url":null,"abstract":"\u0000 The CO2 Dragster competition is performed at a national level as part of the Technology Student Association (TSA), and it seeks to increase and implement STEM skills for high school students. Students are expected to create CO2-powered Dragsters, which are placed on a 20-meter track to compete against each other. The CO2 Dragster consists of a pressure vessel containing CO2, which is placed in a pre-drilled cartridge located at the back of the vehicle. The CO2 propellant is used to provide thrust to the Dragster during the race, and sand smoothed balsawood material is used for the solid body of the Dragster. The CO2 Dragster competition is introduced at the high school level to provide students with a hands-on activity that allows them to learn and apply the fundamentals of fluid dynamics and solid mechanics. The students are placed in charge of designing a 3D model of their Dragster and are required to submit the 3D model with their respective drawings. In this paper, a mathematical, computational, and experimental analysis of a CO2 Dragster is provided. This research consisted of creating a shell model on NX 10, then inserted into ANSYS Fluent to simulate the flow around the model to identify and track the stagnation points, pressure loadings, and flow separation effects caused by the fluid interaction with the Dragster. Mathematical formulas were implemented to find the fracture of slim body CO2 Dragsters, using a coupling between fluid mechanics and solid mechanics, Fluid-Structure Interactions (FSIs). In conclusion, by creating a computational model, it is possible to drive dragster design by simulating different dragster designs’ computationally to improve its performance. Creating a computational functional model to simulate the Dragster, implementing mathematical formulas to understand the behavior, and experimentally evaluating the parameters based on performance will lead to more innovative practices of creating better Dragsters for this competition.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127203167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}