ANALYSIS OF VARIOUS TURBULENCE MODELS FOR NACA 23012 AIRFOIL

IJRAME Publications, 2019

Two dimensional models for the airfoils were created, drawn and meshed in ANSYS Mechanical using geometry data gathered by the National Advisory Committee for Aeronautics. ANSYS FLUENT is used for computing flow over the two dimensional NACA 2415 and 23012 airfoil at an angle of attack of 4°. The computations are carried out at high Reynolds number at standard roughness conditions. One of the popular meshes for simulating an airfoil in a stream is a C-Mesh, and that is what we will be using. At the inlet of the system, we will define the velocity as entering at a 4° angle of attack, and at a total magnitude of 1. We will also define the gauge pressure at the inlet to be 0. As for the outlet, the only thing we can assume is that the gauge pressure is 0. As for the airfoil itself, we will treat it like a wall. From the analysis, C P (Coefficient of Pressure) distribution, C L (Coefficient of Lift) and C D (Coefficient of Drag) is estimated and compared with the experimental results.

2020

The present work is dedicated to conduct a comparative study on identifying the effective turbulence model in terms of flow outlet velocity, error percentage, number of iterations and time coefficient using NACA0012 airfoil by considering Spalart – Allmaras as a reference model. The current study considers 12 different turbulence models including Spalart – Allmaras for obtaining the output characteristics individually. The turbulence models in existence such as Standard K-epsilon, RNG K-epsilon, Realizable variant of Kepsilon, Standard K-Omega, SST K-Omega, BSL K-Omega, Transition K-KL Omega, Transition SST, Reynolds Stress (Linear Pressure Strain), Reynolds Stress (Quadratic Pressure Strain), Reynolds stress (Stress Omega) have been utilized for the evaluation and comparison. The NACA0012 airfoil is modelled using CATIA and the meshed model of the airfoil is analyzed using ANSYS FLUENT under standard boundary conditions. The results obtained have shown that the Standard K – epsilon...

2017

Subsonic turbulent flow over NACA0012 airfoil at the Reynolds number of 3×10 and different angles of attack (from -12o to 20o) is simulated using OpenFOAM. The flow is assumed 133ort steady and two-dimensional. Different turbulence models including Spalart-Allmaras, realizable k-ɛ and k-ω Shear Stress Transport (SST) are employed and their accuracy evaluated through the comparison 133ort h results with the available experimental data. The main focus has been put on the two regions around the airfoil, namely, the transition region and the turbulent region that are of high importance in the evaluation of computational fluid dynamics (CFD) codes. Hence, the laminar to turbulent transition point was determined at various Reynolds numbers in order to get accurate results 133ort he drag coefficient. It was found that by increasing the angle of attack, the accuracy of all the turbulence models used in the OpenFOAM software would reduce. In addition, the SpalartAllmaras model showed highest...

Journal of Engineering Advancements, 2022

This paper presents an evaluation of five different turbulence models by comparing the numerical data derived from these models using ANSYS Fluent with experimental data at a Reynolds number and a Mach number of 0.05 × 106 and 0.015 respectively based on the centerline chord of the airfoil for the flow over NACA 0012 and NACA 2412 airfoils. Moreover, the aim of the present study is to demonstrate the difference in aerodynamic characteristics of the airfoils in order to find aerodynamically more advantageous airfoil. It is concluded that Spalart-Allmaras model and k-ω SST model are capable of providing the most accurate prediction for lift coefficient at a low angle of attack for both airfoils. Standard k - ε model gives a slightly low value of lift coefficient at low angle of attack and slightly high value of lift coefficient at high angle of attack for both airfoils. k-ω SST model, Spalart-Allmaras model, Transition k-kL - ω model, and γ-Rⅇθ Transition SST model can predict drag co...

Processes

In recent years, there has been an increased interest in the old NACA four-digit series when designing wind turbines or small aircraft. One of the airfoils frequently used for this purpose is the NACA 0018 profile. However, since 1933, for over 70 years, almost no new experimental studies of this profile have been carried out to investigate its performance in the regime of small and medium Reynolds numbers as well as for various turbulence parameters. This paper discusses the effect of the Reynolds number and the turbulence intensity on the lift and drag coefficients of the NACA 0018 airfoil under the low Reynolds number regime. The research was carried out for the range of Reynolds numbers from 50,000 to 200,000 and for the range of turbulence intensity on the airfoil from 0.01% to 0.5%. Moreover, the tests were carried out for the range of angles of attack from 0 to 10 degrees. The uncalibrated γ−Reθ transition turbulence model was used for the analysis. Our research has shown tha...

5th International Conference on Engineering, Research, Innovation and Education (ICERIE), 2019

Study of a two-dimensional CFD analysis is done to investigate the effects of angle of attack and Mach number on the aerodynamic characteristics of NACA (National Advisory Committee for Aeronautics) 0012 airfoil considering turbulent flow around it. Different parameters used, and its effects, in analysis like domain shape, grid cells, number of nodes in meshing, various boundary conditions are surveyed. Change in Reynolds number of fluid results in different output, hence the variation of lift & drag coefficient with the change in Reynolds number is analyzed. To show the behavior of the airfoil at these conditions is the main objective of this paper. The simulation is done in ANSYS Fluent and both the k-omega and k-epsilon turbulence modeling method was used to compare the results. From the CL (life Coefficient)/ CD (Drag Coefficient) ratio, it shows that when the Mach number (M) increases, CL increases but CD remains constant at different operating conditions. Moreover, it is observed that the CL/CD ratio decreases because of a rapid downward for the CL and an abrupt upward for the CD with velocity approaching the sonic velocity. Computational results are validated with the results of NASA Langley Research Center validation cases.

Volume 2: Symposia, Parts A, B, and C, 2003

This paper presents computational study of the mean flow and Reynolds stresses results, of a NACA 4412 airfoil, covering the boundary layers around the airfoil and the wake region at angle of attack, α a = 15˚. The ability of using different turbulence models to predict unsteady separated flows over airfoils is evaluated. Two-equation turbulence models are tested for the ability to predict boundary layer separation on NACA 4412 airfoil at the position of maximum lift (α a = 15˚). These models are the two-equation Realizable, RNG k-ε models and the Reynolds Stress Model (RSM). It was found that the developed turbulence models had captured the physics of unsteady separated flow. The resulting surface pressure coefficients, skin friction, velocity vectors, shear stress and kinetic energy are compared with flying hot wire experimental data, and it was found that the models produced very similar results with the experimental data. Also excellent agreement between computational and experimental surface pressures and skin friction was observed.

Open Engineering, 2024

Using computational models and low-speed wind tunnel tests, the aerodynamic characteristics of the NACA 0012 airfoil with low Re numbers of (8 × 10 4 , 2 × 10 5 , 3 × 10 5 , and 4 × 10 5) and angle of attack (AOA) ranging from 0°t o 18°by two steps are examined. Using the same 3-D wind tunnel dimensions, numerical simulations were run. The software program ANSYS FLUENT was used to solve the mathematical model using the continuity equation, the Navier-Stokes equations, and the k-ω shearstress transport turbulence model. Findings demonstrate that at all AOAs, there is a direct relationship between Reynolds numbers (Re), lift and drag coefficients, kinetic energy, and stall angle. The lift coefficient rises linearly as the AOA increases, peaking at 14°, the stall angle at higher Reynolds number. The lift coefficient was found to decline when the AOA was increased further, reaching its minimal value at an AOA of 18°. With a greater AOA, the airfoil's drag coefficient rises, creating turbulent flow. The eddies produced by the turbulence cause the flow to start separating from the airfoil surface as turbulence increases. As a result, the airfoil lift coefficient drops, and its drag coefficient rises at the same time, leading to poor performance. The validation of the numerical results through wind tunnel experiments provided confidence in the findings of the study.

NACA 0012 AIRFOIL IN DIFFERENT HIGH FREESTREAM TURBULENCE INTENSITIES AND ANGLES OF ATTACK AT HIGH REYNOLDS NUMBER, 2024

Analysis of the parameters of airfoils for better optimization of flying has been done for years because better parameters mean better cost and efficiency. Considering the existence of turbulence, the intensity of the turbulence affects the flow's boundary layer separation in most of the airflow. An airfoil's aerodynamics characteristic mainly depends on the flow characteristics such as separation and reverse flow. The difference in pressure between the upper and lower surface of the airfoil creates the force called lift force, which allows the plane to fly. The pressure coefficient is significant when calculating the pressure difference between the upper and lower surfaces. In this study, the effect of varied high freestream turbulence intensity on pressure coefficient in 2D NACA 0012 airfoil at high Reynolds number was observed computationally using ANSYS-Fluent software. Outcomes were compared with experimental results of the two-dimensional wind tunnel test of the symmetrical NACA 0012 airfoil in NASA. Angle of attacks are 1.86°, 3.86°, 5.86°, 7.86° respectively while turbulence intensities are %5, %10, %15, %20, %25, and %30 respectively. A high Reynolds number was taken (Re=3x10 6). Because the Mach number is 0.3, the flow was assumed to be incompressible. The flow regime was considered a steady state, and gravity was ignored.

2021

Proper blade design, selection and use continue to gain importance with the developing technology, aviation and space industry. Many applications use wings such as aircraft (planes, helicopters, etc.), UAV (Unmanned Aerial Vehicle), wind turbines and so on. This study covers a NACA 0009 profiled wing with a 111 mm span and chord and its CFD analysis using Ansys version 15.0. Three-dimensional analysis has been done using Ansys Fluent. A geometry was created, this geometry was meshed properly, tighter especially close to the wings, and its analysis was completed using the k-w turbulence model. In total 2,078,272 nodes and 2,036,295 elements have been formed in the mesh. Four different angles of attack have been tested which are 0°, 5°, 10° and 15° at 37,000 Reynolds number. Generated mesh has an average skewness rate of 1.3 and an average orthogonal quality rate of 0.97. Velocity contours and streamlines have been compared to the literature. Lift and drag coefficients have been monit...