Numerical Study of NACA 0012 Aeroacoustics Response for Normal and Icing Conditions

2018 ◽  
Vol 875 ◽  
pp. 89-93
Author(s):  
Edison H. Caicedo ◽  
Muhammad S. Virk
Keyword(s):  
Numerical Study ◽  
Turbulence Models ◽  
Aerodynamic Characteristics ◽  
Sound Level ◽  
Detached Eddy Simulation ◽  
Blade Profile ◽  
Eddy Simulation ◽  
Naca0012 Airfoil ◽  
Layer Flow ◽  
Naca 0012

This paper describes a multiphase computational fluid dynamics (CFD) based numerical study about aeroacoustics response of NACA0012 airfoil for both normal and icing conditions. Three different turbulence models (RANS, DES & LES) are tested where Detached Eddy simulation (DES) turbulence modelling approach is found suitable for this case study. Aeroacoustics numerical results for clean NACA 0012 are compared with the experimental data obtained from NASA report 1218 [1], where a good agreement is found. An extended CFD study is carried out for iced NACA 0012 airfoil, where results show more boundary layer flow separation in case of iced blade profile that leads to a change in the aerodynamic characteristics of the blade profile and increase in sound level for iced airfoil as compared to the clean NACA0012 airfoil.

Aeroacoustics response of wind turbine blade profiles in normal and icing conditions

2018 ◽  
Vol 42 (3) ◽  
pp. 243-251 ◽  
Author(s):  
Edison H Caicedo ◽  
Muhammad S Virk
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Numerical Study ◽  
Turbulence Models ◽  
Wind Turbine Blade ◽  
Navier Stokes ◽  
Detached Eddy Simulation ◽  
Eddy Simulation

This article describes a multiphase computational fluid dynamics–based numerical study of the aeroacoustics response of symmetric and asymmetric wind turbine blade profiles in both normal and icing conditions. Three different turbulence models (Reynolds-averaged Navier–Stokes, detached eddy simulation, and large eddy simulation) have been used to make a comparison of numerical results with the experimental data, where a good agreement is found between numerical and experimental results. Detached eddy simulation turbulence model is found suitable for this study. Later, an extended computational fluid dynamics–based aeroacoustics parametric study is carried out for both normal (clean) and iced airfoils, where the results indicate a significant change in sound levels for iced profiles as compared to clean.

Numerical Study of Flow Physics Behind the Aerodynamic Performance on an Airfoil With Leading Edge Tubercles

2016 ◽  
Author(s):  
Mingming Zhang ◽  
Ming Zhao ◽  
Jianzhong Xu
Keyword(s):  
Numerical Study ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Physical Models ◽  
Vortical Flow ◽  
Detached Eddy Simulation ◽  
Flow Physics ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation ◽  
Solid Foundation

This paper presents a numerical analysis of the flow physics behind the effects of leading-edge protuberances on airfoil performances at low Reynolds number with an aim to provide a solid foundation for the engineering applications in the near future. An improved delayed detached eddy simulation (IDDES) method based on a transition model was proposed and validated through comparisons with experimental results. Utilizing the IDDES scheme, together with vortex dynamic method, investigations were focused on the stall and post-stall regions, respectively. It was found that an interesting ‘bi-periodic’ phenomenon within stall region, i.e. converged and diverged vortical flow in adjacent trough sections of tubercles, was created with the complicated evolution of the generated streamwise counter-rotating vortex pairs, resulting in the degraded aerodynamic characteristics as well as rather gentle stall process. For the post-stall cases, the impaired flow detachment around both peak and trough sections of tubercles were responsible for the improved airfoil performance. In addition, two physical models within the two regions were also built to further clarify the flow physics in a general way.

A numerical study of aerodynamic characteristics of a high-speed train with different rail models under crosswind

2020 ◽  
pp. 095440972096925
Author(s):  
Zhiwei Jiang ◽  
Tanghong Liu ◽  
Houyu Gu ◽  
Zijian Guo
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
Pressure Distributions ◽  
Significant Difference ◽  
Aerodynamic Performances ◽  
Yaw Angle

The CFD (Computational Fluid Dynamics) numerical simulation method with the DES (detached eddy simulation) approach was adopted in this paper to investigate and compare the aerodynamic performance, pressure distributions of the train surface, and flow fields near the train model placed above the subgrade with non-rail, realistic rail, and simplified rail models under crosswind. The numerical methods were verified with the wind tunnel tests. Significant differences in aerodynamic performances of the train body and bogie were found in the cases with and without a rail model as the presence of the rail model had significant impacts on the flow field underneath the vehicle. A larger yaw angle can result in a more significant difference in aerodynamic coefficients. The deviations of the train aerodynamic forces and the pressure distribution on the train body with the realistic and simplified rail models were not significant. It was concluded that a rail model is necessary to get more realistic results, especially for large yaw angle conditions. Moreover, a simplified rectangular rail model is suggested to be employed instead of the realistic rail and is capable to get accurate results.

Numerical study on the dynamics and mass transfer characteristics of a radial offset jet

2014 ◽  
Vol 31 (3) ◽  
pp. 406-424 ◽  
Author(s):  
Zhiwei Li ◽  
Wenxin Huai ◽  
Zhonghua Yang ◽  
Zhongdong Qian ◽  
Yuhong Zeng
Keyword(s):  
Mass Transfer ◽  
Numerical Study ◽  
Turbulence Models ◽  
Recirculation Region ◽  
Detached Eddy Simulation ◽  
Reynolds Stresses ◽  
Content Type ◽  
Transfer Characteristics ◽  
Eddy Simulation ◽  
Offset Jet

Purpose – A radial offset jet has the flow characteristics of a radial jet and an offset jet, which are encountered in many engineering applications. The purpose of this paper is to study the dynamics and mass transfer characteristics of the radial offset jet with an offset ratio 6, 8 and 12. Design/methodology/approach – Three turbulence models, namely the SST k-? model, detached eddy simulation model, and improved delayed detached eddy simulation (IDDES), were applied to the radial offset jet with an offset ratio eight and their results were compared with experimental results. The contrasting results, such as the distributions of mean and turbulent velocity and pressure, show that the IDDES model was the best model in simulating the radial offset jet. The results of the IDDES were analyzed, including the Reynolds stress, turbulent kinetic energy, triple-velocity correlations, vertical structure and the tracer concentration distribution. Findings – In the axisymmetric plane, Reynolds stresses increase to reach a maximum at the location where the jet central line starts to be bent rapidly, and then decrease with increasing distance in the radial direction. The shear layer vortices, which arise from the Kelvin-Helmholtz instability near the jet exit, become larger scale results in the entrainment and vortex pairing, and breakdown when the jet approaches the wall. Near the wall, the vortex swirling direction is different at both front and back of attachment point. In the wall-jet region, the concentration distributions present self-similarity while it keeps constant below the jet in the recirculation region. Research limitations/implications – The radial offset jet with other offset ratio and exit angle is not considered in this paper and should be investigated. Originality/value – The results obtained in this paper will provide guidance for studying similar flow and a better understanding of the radial offset jet.

scholarly journals Numerical study of the aerodynamic characteristics around typical terrain with different temperature

2020 ◽  
Vol 185 ◽  
pp. 02021
Author(s):  
Xiaowei Huai ◽  
Li Li ◽  
Jun Guo ◽  
Shifeng Wu ◽  
Zhou Jian
Keyword(s):  
Surface Temperature ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Detached Eddy Simulation ◽  
Near Surface ◽  
Local Climate ◽  
Buoyant Flows ◽  
Eddy Simulation ◽  
Speedup Ratio ◽  
Meteorological Elements

The distributions of near-surface meteorological elements, such as wind, are greatly affected by the terrain underneath, which makes the power structure of micro geomorphic area more vulnerable to the influence of local climate. Single hills with length are one of typical terrains in microrelief. In this paper, the circulation caused by buoyant flows and temperate within typical single hilly terrain with length is studied. The Detached Eddy Simulation (DES) is used to integrate buoyancy, turbulence and micro-terrain into a single model and it is applied to the special situation of micro-terrain climate. How the wind field is influ-enced by different surface temperature and the model surface roughness is carefully described. The results show that, different surface temperature has a very strong effect on the speedup ratio. Compared with the air temperature, the lower the terrain surface temperature is, the more obvious the speedup ratio effect is, and vice versa. For different roughness surface terrain, the speedup ratio has almost the same characteristics.

Numerical Modeling of Stall and Poststall Events of a Single Pitching Blade of a Cycloidal Rotor

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Kuldeep Singh ◽  
José Carlos Páscoa
Keyword(s):  
Critical Points ◽  
Numerical Study ◽  
Turbulence Models ◽  
Detached Eddy Simulation ◽  
Wake Vortices ◽  
Eddy Simulation ◽  
Reduced Frequency ◽  
Moderate Reynolds Number ◽  
Lift And Drag ◽  
Low Amplitude

In the present work, a numerical study is carried out to compare the performance of seven turbulence models on a single pitching blade of cycloidal rotor operating in deep dynamic stall regime at moderate Reynolds number. The investigated turbulence models were: (i) kω-shear stress transport (SST), (ii) kω-SST with γ, (iii) transition SST (γ–Reθ), (iv) scale adaptive simulation (SAS), (v) SAS coupled with transition SST, (vi) SAS with γ, and (vii) detached eddy simulation (DES) coupled with transition kω-SST. The wake vortices evolution and shedding analysis are also carried out for the pitching blade. The performance of the investigated turbulence models is evaluated at various critical points on the hysterias loop of lift and drag coefficients. The predictions of the investigated turbulence models are in good agreement at lower angle of attack, i.e., αu ≤ 20 deg. The detailed quantitative analysis at critical points showed that the predictions of SAS and transition SST-SAS turbulence models are in better agreement with the experimental results as compared to the other investigated models. The wake vortices analysis and fast Fourier transport analysis showed that the wake vortex characteristics of a pitching blade are significantly different than those for the low amplitude oscillating blade at the higher reduced frequency.

Assessment of turbulence models for transonic oscillating airfoil

2017 ◽  
Vol 27 (11) ◽  
pp. 2603-2628 ◽  
Author(s):  
Mojtaba Tahani ◽  
Mehran Masdari ◽  
Hamidreza Eivazi ◽  
Massoud Tatar
Keyword(s):  
Transonic Flow ◽  
Turbulence Models ◽  
Nonlinear Flow ◽  
Nonlinear Phenomena ◽  
Detached Eddy Simulation ◽  
Aerodynamic Coefficients ◽  
Content Type ◽  
Eddy Simulation ◽  
Naca0012 Airfoil ◽  
Delayed Detached Eddy Simulation

Purpose This paper aims to investigate numerical solution of transonic flow around NACA0012 airfoil under sinusoidal pitch oscillation. Accordingly, effects of the amplitude and frequency of oscillations on aerodynamic coefficients are evaluated and the efficiency of the turbulent models, K-ω shear-stress transport (SST), scale adaptive simulation (SAS) and delayed detached eddy simulation (DDES), in simulation of the nonlinear phenomena – i.e. the interaction between shock and boundary layer and the shock oscillations – is studied. Design/methodology/approach K-ω SST, SAS and DDES models are used as turbulence approaches. The numerical results are compared with available experimental and numerical information. Findings According to the results inside the buffet boundaries, the DDES turbulent model expresses results that are more appropriate; however, SAS and SST models are not efficient enough in evaluating the characteristics of nonlinear flow. Originality/value In this research study, hybrid RANS-LES turbulence model is engaged to simulate transonic flow around pitching NACA0012 airfoil, and results are compared to the SAS and Reynolds Average Navier–Stocks simulations as well as available numerical and experimental data. In addition, effects of the amplitude and frequency of oscillations on aerodynamic coefficients are evaluated in buffet regions.

Numerical Study on a Single Square Cylinder Subjected to Vortex-Induced Vibration in HTR-PM

2016 ◽  
Author(s):  
Qiankun Xiao ◽  
Li Shi ◽  
Xiaoxin Wang ◽  
Xiaowei Luo ◽  
Xinxin Wu
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Numerical Study ◽  
Flow Direction ◽  
Turbulence Models ◽  
Detached Eddy Simulation ◽  
Square Cylinder ◽  
Vortex Induced Vibration ◽  
Eddy Simulation ◽  
High Reynolds

The heat transfer tube bundles of the steam generator in high temperature reactor pebble bed module (HTR-PM) are subjected to high speed helium flow, which might lead to vortex-induced vibration (VIV). In the present paper, to investigate the vibration of square cylinder under flow effect, vortex shedding phenomena of a stationary square cylinder at a high Reynolds number equal to 6.8 × 104 is simulated by detached eddy simulation (DES) turbulence models. A comparatively close agreement with previous experimental results is achieved. Combining computational fluid dynamics (CFD) and computational structural dynamics (CSD) methods, a fluid-structure-interaction (FSI) model for VIV of the square cylinder is then established, and vibration response perpendicular to flow direction were investigated. Moreover, the safe range of the natural frequency of the square cylinder to avoid synchronized vibration with VIV is analyzed. The results of this paper can provide an important guidance to the design of the heat transfer tubes and their supports in HTR-PM.

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