Influence of the Curvature Correction on Turbulence Models for the Prediction of the Aerodynamic Coefficients of the S809 Airfoil

2021 ◽  
Vol 43 ◽  
pp. 45-57
Author(s):  
Mohammed Nebbache ◽  
Abdelkader Youcefi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Lift Coefficient ◽  
Turbulence Models ◽  
Aerodynamic Coefficients ◽  
Ansys Fluent ◽  
Curvature Correction ◽  
Shear Stress Transport ◽  
Sst Model

Using the appropriate procedure, Computational Fluid Dynamics allows predicting many things in several fields, and especially in the field of renewable energies, which has become a promising research axis. The present study aims at highlighting the influence of the curvature correction on turbulence models for the prediction of the aerodynamic coefficients of the S809 airfoil using the Computational Fluid Dynamics code ANSYS Fluent 17.2. Three turbulence models are used: Spalart-Allmaras, Shear Stress Transport k-ω and Transition SST. Experimental results of the 1.8 m × 1.25 m low-turbulence wind tunnel at the Delft University of Technology are used in this work for comparison with the numerical results for a Reynolds number of 106. The results show that the use of the curvature correction improves the prediction of the aerodynamic coefficients for all the turbulence models used. A comparison of the three models is also made using curvature correction since it gave better results. The Transition SST model is the one that gives the best results for the lift coefficient, followed by the Shear Stress Transport kω model, and finally the Spalart-Allmaras model. For the drag coefficient, Transition SST model is the best, followed by the Spalart-Allmaras model, and finally the Shear Stress Transport kω model.

Turbulence modeling effects on the aerodynamic characterizations of a NASCAR Generation 6 racecar subject to yaw and pitch changes

2019 ◽  
Vol 233 (14) ◽  
pp. 3600-3620 ◽  
Author(s):  
Chen Fu ◽  
C Patrick Bounds ◽  
Christian Selent ◽  
Mesbah Uddin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Eddy Viscosity ◽  
Turbulence Models ◽  
Flow Region ◽  
Adverse Pressure Gradient ◽  
Navier Stokes ◽  
Shear Stress Transport ◽  
Reynolds Averaged Navier Stokes

The characterization of a racecar’s aerodynamic behavior at various yaw and pitch configurations has always been an integral part of its on-track performance evaluation in terms of lap time predictions. Although computational fluid dynamics has emerged as the ubiquitous tool in motorsports industry, a clarity is still lacking about the prediction veracity dependence on the choice of turbulence models, which is central to the prediction variability and unreliability for the Reynolds Averaged Navier–Stokes simulations, which is by far the most widely used computational fluid dynamics methodology in this industry. Subsequently, this paper presents a comprehensive assessment of three commonly used eddy viscosity turbulence models, namely, the realizable [Formula: see text] (RKE), Abe–Kondoh–Nagano [Formula: see text], and shear stress transport [Formula: see text], in predicting the aerodynamic characteristics of a full-scale NASCAR Monster Energy Cup racecar under various yaw and pitch configurations, which was never been explored before. The simulations are conducted using the steady Reynolds Averaged Navier–Stokes approach with unstructured trimmer cells. The tested yaw and pitch configurations were chosen in consultation with the race teams such that they reflect true representations of the racecar orientations during cornering, braking, and accelerating scenarios. The study reiterated that the prediction discrepancies between the turbulence models are mainly due to the differences in the predictions of flow recirculation and separation, caused by the individual model’s effectiveness in capturing the evolution of adverse pressure gradient flows, and predicting the onset of separation and subsequent reattachment (if there be any). This paper showed that the prediction discrepancies are linked to the computation of the turbulent eddy viscosity in the separated flow region, and using flow-visualizations identified the areas on the car body which are critical to this analysis. In terms of racecar aerodynamic performance parameter predictions, it can be reasonably argued that, excluding the prediction of the %Front prediction, shear stress transport is the best choice between the three tested models for stock-car type racecar Reynolds Averaged Navier–Stokes computational fluid dynamics simulations as it is the only model that predicted directionally correct changes of all aerodynamic parameters as the racecar is either yawed from the 0° to 3° or pitched from a high splitter-ground clearance to a low one. Furthermore, the magnitude of the shear stress transport predicted delta force coefficients also agreed reasonably well with test results.

Analysis and research on vehicle wading performance

2020 ◽  
Vol 235 (1) ◽  
pp. 3-15
Author(s):  
Zheng Xin ◽  
Su Donghai
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Fluid Model ◽  
Dynamics Simulation ◽  
Turbulent Model ◽  
Wheel Rotation ◽  
Shear Stress Transport ◽  
Vof Model ◽  
Computational Fluid Dynamics Analysis

With the inclusion of the effects from wheels rotation, vehicle wading phenomenon was simulated using computational fluid dynamics tools and compared with road wading test. The new method utilizing the volume of fluid model to simulate the two-phase (water and air) flow when vehicle wades, Reynolds-Averaging Navier–Stokes simulation with both Realizable and shear stress transport turbulent models were conducted and the results indicated that the essential features of vehicle wading phenomenon were captured accurately. A relatively better correlation is achieved between computational fluid dynamics analysis and road test when shear stress transport turbulent model was utilized compared to using Realizable turbulent model. With the addition of the wheel rotation effects in vehicle wading simulation, the potential risks of water intrusion into the critical chassis and electronic components can be early detected and the frequent late design changes can be avoided. The new approach adopted in this study with VOF model and RANS simulation with SST turbulent model has shown that the benefits of shorter vehicle development cycles and parts warranty cost reduction. Thus, the results from computational fluid dynamics simulation with wheel rotation effects included can serve as the design guidance for any future vehicle wading developments.

scholarly journals STUDY OF MESH REFINEMENT ON THE AERODYNAMIC COEFFICIENTS FOR NACA2412 PROFILE WITH DIFFERENT ANGLE OF ATTACK AND k - w TURBULENCE MODEL

2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Nícolas Lima Oliveira ◽  
Eric Vargas Loureiro ◽  
Patrícia Habib Hallak
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Coefficient ◽  
Turbulence Model ◽  
Lift Coefficient ◽  
Mesh Refinement ◽  
Angle Of Attack ◽  
Aerodynamic Coefficients ◽  
Computational Fluid Dynamics Cfd

This work presents the studies  obtained using OpenFOAM OpenSource Computational Fluid Dynamics (CFD) Software. Experiments were performed to predict lift coefficient and drag coefficient curves for the NACA2412 profile. Subsequently, the results obtained were compared with the results of the bibliography and discussed.

An Assessment of Turbulence Models in Simulating a Synthetic Jet

2013 ◽  
Vol 465-466 ◽  
pp. 603-607
Author(s):  
Greg G. Gomang ◽  
Ann Lee
Keyword(s):  
Experimental Data ◽  
Shear Stress ◽  
Numerical Study ◽  
Cross Flow ◽  
Turbulence Models ◽  
Synthetic Jet ◽  
Shear Stress Transport ◽  
Sst Model ◽  
Realistic Prediction ◽  
Good Agreement

This paper presents a two-dimensional numerical study on the interaction of synthetic jet and the cross flow inside a microchannel. Three different turbulence models namely the standard k-, Shear Stress Transport (SST) and Scale Adaptive Simulation Shear Stress Transport (SAS SST) were tested for their ability to predict the flow structure generated by a synthetic jet. The results are validated against existing experimental data. The SAS SST model was found to give the most realistic prediction of the fluid flow based on the good agreement with experimental data.

scholarly journals Mixing Performance of Counter-Axial Flow Impeller using Computational Fluid Dynamics

2018 ◽  
Vol 8 (02) ◽  
Author(s):  
Ian Torotwa ◽  
Changying Ji
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Axial Flow ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Ansys Fluent ◽  
Rushton Turbine ◽  
Mixing Performance ◽  
Computational Fluid Dynamics Cfd

In this study, turbulent flow fields in a baffled vessel stirred by counter-axial flow impeller have been investigated in comparison to the Rushton turbine. The resultant turbulence was numerically predicted using computational fluid dynamics (CFD). Turbulence models were developed in ANSYS Fluent 18.1 solver using the Navier-Stokes equation with the standard k-ε turbulence model. The Multiple Reference Frame (MRF) approach was used to simulate the impeller action in the vertical and horizontal planes of the stirred fluid volume. Velocity profiles generated from the simulations were used to predict and compare the performance of the two designs. To validate the CFD model, the simulation results were compared with experimental results from existing work and a satisfactory agreement was established. It was concluded that the counter-axial flow impeller could provide better turbulence characteristics that would improve the quality of mixing systems.

scholarly journals Pengaruh Jumlah Sudu 8, 12, 16 dan 20 terhadap Performa Hidro-Turbin Cross-Flow dengan sudut 15° Menggunakan Metode Computational Fluids Dynamics

2021 ◽  
Vol 6 (2) ◽  
pp. 88
Author(s):  
Dandun Mahesa Prabowoputra
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Steady State ◽  
Cross Flow ◽  
Computational Fluids Dynamics ◽  
Shear Stress Transport ◽  
Computational Fluids

<p>Energi listrik merupakan kebutuhan primer dalam kehidupan sehari-hari. Perkembangan teknologi mengakibatkan meningkatnya kebutuhan energi listrik setiap tahunnya. Energi baru terbarukan memasok kebutuhan energi listrik nasional sebesar 14%. Di sisi lain, pemerintah mengharapkan komposisi energi baru terbarukan sebesar 23% hingga 31% pada tahun 2050. Hal ini menunjukan bahwa energi baru terbarukan masih memiliki gap yang cukup tinggi. Penelitian ini merupakan salah satu upaya dalam pengembangan energi baru terbarukan, terutama pada pembangkit listrik mikro-pico hidro. Penelitian ini dilakukan menggunakan metode <em>Computational Fluid Dynamics</em> menggunakan Aplikasi Ansys dengan CFX <em>Solver</em>. Penelitian dilakukan untuk mengetahui pengaruh jumlah sudu pada hidro-turbin <em>cross-flow</em> terhadap performa <em>Coefficient of Power</em>. Peneltian dilakukan pada rotor dengan dimensi diameter 80 mm, panjang 130 mm dan sudut sudu 15°. Variasi jumlah sudu dilakukan pada jumlah sudu 8, 12, 16, dan 20. Simulasi dilakukan pada <em>steady state,</em> dan menggunakan tipe turbulen <em>Shear Stress Transport</em>. Turbin <em>cross-flow</em> beroperasi pada kecepatan air 3m/s dengan kecepatan sudut pada interval 50 sampai 350 RPM.  Hasil menunjukan <em>Coefficient of Power Maximum</em> yang dihasilkan untuk sudu 8,12, 16 dan 20 adalah 10,8%; 14,1%; 16,8% dan 20,1%. Dari hasil tersebut menunjukan performa maksimal dihasilkan oleh hidro-turbin tipe <em>cross-flow</em> dengan jumlah sudu rotor 20.</p>

scholarly journals Effect of turbulence models' choice on the aero-thermal flow numerical validations within a ribbed trailing edge geometry

2018 ◽  
Vol 233 (1) ◽  
pp. 52-77 ◽  
Author(s):  
A Beniaiche ◽  
M Nadir ◽  
M Cerdoun ◽  
C Carcasci ◽  
B Facchini
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cooling System ◽  
Turbulence Models ◽  
Thermochromic Liquid Crystal ◽  
Trailing Edge ◽  
Ansys Fluent ◽  
Numerical Predictions ◽  
Accuracy Of Results ◽  
Scaled Models

In this paper, the commercial ANSYS Fluent software was used to achieve a numerical survey of the effect of five (05) turbulence models’ formulation on the aero-thermal computational fluid dynamics validation of two 30:1 scaled models reproducing an original internal ribbed trailing edge prototype. Tests were conducted for stationary and rotation conditions, for Re = 10,000–40,000 and Ro = 0–0.23. Particle image velocimetry and thermochromic liquid crystal experimental data were employed to check the consistence computational fluid dynamics results qualitatively and quantitatively, aerodynamically and thermally, for various working conditions. Numerical predictions revealed that the choice of the turbulence model affects the accuracy of results. Concerning the shear stress transport k-w model, limiters defined in the eddy viscosity formulation induce a surplus estimation of the turbulence kinetic energy ( k) which leads to noticeable discrepancies in terms of velocity profiles and recirculation zones. Also, numerical calculations confirmed former experimental assumptions concerning origins of the aerodynamic structures and heat transfer's features, especially, those related to the increase of the cooling temperature balance efficiency, the appearance/disappearance of the horseshoe structures within the trailing edge region and velocities/boundary layers’ profile variations. The obtained results assist the understanding and the forecast of the flow field behavior, throughout the design process, by the assessment of the aerodynamic and thermal performances within the considered blade's cooling system.

FLUCTUACIONES INDUCIDAS DEL FLUJO DE AIRE EN UN DUCTO CON PAREDES DENTADAS

2020 ◽  
Vol 24 (105) ◽  
pp. 63-71
Author(s):  
San Luis B. Tolentino Masgo ◽  
Juan Toledo Hernández
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shock Waves ◽  
Materials Science ◽  
Turbulence Modeling ◽  
Dynamic Instability ◽  
Fluid Dynamic ◽  
Turbulence Models ◽  
Ansys Fluent ◽  
Fluids Mechanics

Estudios experimentales y numéricos han centrado el interés en el campo de flujo con superficies de paredes dentadas y cavidades, donde la turbulencia del flujo son captadas en imágenes con la técnica Schlieren y recreadas con códigos computacionales. En el presente trabajo, se realiza un estudio numérico para el flujo de aire en un ducto recto con paredes dentadas para seis casos de presión. El flujo se simuló para un dominio computacional 2D con el código ANSYS-Fluent, para lo cual se empleó el modelo RANS en conjunto con el modelo de turbulencia de Menter. Se obtuvieron los campos de número de Mach, velocidad, presión y temperatura con presencia de remolinos y ondas de choque. En ciertas regiones el flujo presentó desviaciones al chocar con las esquinas de los dientes, por lo cual originó fluctuaciones inducidas de los parámetros termodinámicos aguas abajo y hacia la región del centro; en los espacios entre dientes se presentó remolinos; al final del último diente se presentó ondas de choque oblicuas. Se concluye que la sección dentada incrementa la turbulencia e influye a que la velocidad del flujo tenga un incremento escalonado en régimen transónico. Palabras Clave: ducto, flujo de aire, fluctuación, onda de choque, pared dentada, simulación. Referencias [1]J. Blazek, Computational fluid dynamics: principles and applications. Butterworth- Heinemann, 2015. [2]B. Andersson, R. Andersson, L. Håkansson, M. Mortensen, R. Sudiyo, B. van Wachem, y L. Hellström, Computational Fluid Dynamics Engineers. Cambridge University Press, 2012. [3]T. V. Karman, “The fundamentals of the statistical theory of turbulence,” Journal of the Aeronautical Sciences, vol. 4, no. 4, pp. 131–138, 1937. doi: 10.2514/8.350. [4]F. White, Viscous fluid flow. McGraw-Hill Education, 2005. [5]H. Schlichting, Boundary-layer theory. McGraw-Hill classic textbook reissue series, 2016. [6]J. D. Anderson, Fundamentals of aerodynamics. McGraw-Hill series in aeronautical and aerospace engineering, 2017. [7]D. C. Wilcox, Turbulence modeling for CFD. DCW Industries, 2006. [8]P. Krehl y S. Engemann, “August toepler — the first who visualized shock waves,” Shock Waves, vol. 5, no. 1, pp. 1–18, Jun 1995. doi: 10.1007/BF02425031. [9]G. S. Settles, “Toma ultrarrápida de imágenes de ondas de choque, explosiones y disparos,” Revista Investigación y Ciencia, pp. 74-83, May. 2006. https://www.investigacionyciencia.es [10]H. Hirahara, M. Kawahashi, M. U, Khan y K. Hourigan, “Experimental investigation of fluid dynamic instability in a transonic cavity flow,” Experimental Thermal and Fluid Science, 31, pp. 333–347, 2007. doi: 10.1016/j.expthermflusci.2006.05.007. [11]S. L. Tolentino, S. Caraballo, J. Toledo, J. Mírez y C. Torres, “Oscilaciones de la velocidad del flujo en un ducto recto con cavidades rectangulares,” XVI Jornadas de Investigación 2018, UNEXPO Puerto Ordaz, Venezuela, pp. 34-39, 2018. [12]S. Jeyakumar, K. A. Yuvaraj, K. Jayaraman, F. Cardona y M. T. Sultan, “Effect of cavity fore wall modifications in supersonic flow,” Conference, Materials Science and Engineering, 152, pp. 1-7, 2016. doi: 10.1088/1757-899X/152/1/012002. [13]S. L. Tolentino and S. Caraballo, “Estudio del flujo de aire en un conducto recto con pared dentada,” XIV Jornadas de Investigación 2016, UNEXPO Puerto Ordaz, Venezuela, pp. 203-210, 2016. [14]F. White, Fluids Mechanics. McGraw-Hill Education, 2016. [15]F. R. Menter, “Two equation eddy-viscosity turbulence models for engineering applications,” AIAA Journal, vol. 32, no. 8, pp. 1598-1605, 1994. doi: 10.2514/3.12149. [16]S. L. B. Tolentino Masgo, “Evaluación de modelos de turbulencia para el flujo de aire en una tobera plana,” Revista Ingenius, no. 22, pp. 25-37, Julio-Diciembre 2019. doi: 10.17163/ings.n22.2019.03. [17]S. L. B. Tolentino Masgo, “Evaluación de modelos de turbulencia para el flujo de aire en un difusor transónico,” Revista Politécnica, vol. 45, no. 1, pp. 25-38, 2020. doi: 10.3333/rp.vol45n1.03.

scholarly journals ANALISA PERFORMA HIDRO-TURBIN CROSS-FLOW DENGAN SUDUT DIAMETER RUNNER 10° DAN JUMLAH SUDU 8, 16, DAN 24 MENGGUNAKAN METODE CFD

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Muhammad Mu'izzul As'ad ◽  
Ahmad Janan Febrianto ◽  
Dandun Mahesa Prabowoputra
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Renewable Energy ◽  
Angular Velocity ◽  
Cross Flow ◽  
Shear Stress Transport ◽  
Computational Fluid Dynamics Cfd

Hidro turbin adalah salah satu komponen utama pada pembangkit listrik tenaga air. Penelitian terhadap turbin air memiliki peran penting dalam pengembangan renewable energy yang bersumber dari tenaga hidro. Dimana Indonesia memiliki potensi sumber energi hidro yang sangat besar. Hidro-turbin memiliki beberapa jenis yaitu turbin Sumbu Horizontal, Turbin Sumbu vertical dan turbin Cross-Flow. Penelitian ini dilakukan pada turbin air tipe Cross-Flow, dan dilakukan dengan metode Computational Fluid Dynamics (CFD). Simulasi dilakukan secara tiga dimensi dan menggunakan perangkat lunak Ansys Student 2021 dengan solver CFX. Turbin cross-flow menggunakan runner dengan sudut 10°, dengan variasi jumlah sudu 8, 16, dan 24. Penelitian ini bertujuan untuk mengetahui performa turbin Cross-flow dan mengetahui pengaruh jumlah sudu pada performa tersebut. Turbin Cross-flow beroperasi pada kecepatan fluida 3m/s dan angular velocity 50-250 rpm. Simulasi menggunakan tipe turbulensi Shear Stress Transport dalam kondisi tunak, Hasil menunjukan turbin cross-flow dengan sudut runner 10o dan jumlah sudu 24 memiliki performa terbaik bila dibandingkan dengan jumlah sudu 8 dan 16.

scholarly journals CFD (Computational Fluid Dynamics) Modeling on Narasena Bengawan UV Team Quickster UAV Wings with Addition of Vortex Generator to Aerodynamic Performance

2021 ◽  
Vol 20 (2) ◽  
pp. 77
Author(s):  
Mohammad Fahmi Luthfi ◽  
Dominicus Danardono ◽  
Eko Budi Prasetya ◽  
Yudi Kurniawan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Lift Coefficient ◽  
Vortex Generator ◽  
Aerodynamic Performance ◽  
Navier Stokes ◽  
Dynamics Modeling ◽  
Ansys Fluent ◽  
Computational Fluid Dynamics Modeling

This research is based on obtaining the best possible aerodynamic performance for the Quickster Narasena Bengawan UV Team UAV aircraft wing design. One of the factors that greatly affects the flying performance of a UAV is the wing. The wing on the Quickster Narasena UAV aircraft uses an MH33 airfoil, because MH33 is specifically for high-speed UAV aircraft. This research will discuss the comparison of the performance of a wing without a vortex generator with a wing with a vortex generator. Variations in the positioning of the vortex generator on the wing of the Quickster Narasena UAV will also be discussed in this study. The method used in this research is the CFD (Computational Fluid Dynamics) method. The simulation process will use the ANSYS Fluent 19.0 application with the K-Omega SST method with the Reynolds-Averaged-Navier-Stokes (RANS) equation as the basis. The purpose of this study is to obtain the results of the coefficient of drag, lift, and the contour of the turbulence that will occur. The simulation results that have been done are the geometry of the wing with the addition of a vortex generator can reduce the drag coefficient and can increase the lift coefficient.

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