Unsteady aerodynamics of a pitching NACA 0012 airfoil at low Reynolds number

Kurtuluş, Dilek Funda

doi:10.1177/1756829319890609

Cited by 16 publications

(6 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this study, CFD method 30,31 is used to calculate the flow field and aerodynamic force of two-dimensional propulsive wing. In this section, the numerical method and application process of CFD software ANSYS Fluent in numerical simulation are briefly given.…”

Section: Methodsmentioning

confidence: 99%

Numerical study on aerodynamic characteristics of two-dimensional propulsive wing in cruise and hover

Wang

et al. 2022

International Journal of Micro Air Vehicles

View full text Add to dashboard Cite

The propulsive wing vehicle is a new concept vehicle, which is driven by a cross-flow fan (CFF) embedded in the trailing edge of the wing. The propulsive wing vehicle is capable of cruising and hovering at high angles of attack with very high aerodynamic force coefficients, and has the potential to become a new type of vertical take-off and landing (VTOL) vehicle. The cruise and hover states of the propulsive wing vehicle are defined, and a numerical model of the two-dimensional propulsive wing is established. Based on the computational fluid dynamics (CFD) method, the rotation of the CFF is simulated by using the sliding mesh technique. The effects of cruise speed, angle of attack and CFF rotation speed on the aerodynamics of the two-dimensional propulsive wing are evaluated, and the mechanism of the propulsive wing flow field changes is revealed. The results show that the propulsive wing has a very high lift coefficient of up to 60 at low speed and high angle of attack cruise, and a high thrust coefficient of up to 40 at low speed and small angle of attack cruise. The aerodynamic force of the propulsive wing fluctuates periodically with the rotation of the CFF, and the amplitude of the fluctuation is related to the vorticity of the CFF blade shedding vortex. In hover, the flow field of the propulsive wing is affected by the geometry and wake deflection into an asymmetric distribution, forming a vortex on each side of the airfoil, and the vortex diameter varies with the CFF rotation speed, which in turn has an impact on the hovering performance of the propulsive wing.

show abstract

Section: Methodsmentioning

confidence: 99%

Numerical study on aerodynamic characteristics of two-dimensional propulsive wing in cruise and hover

Wang

et al. 2022

International Journal of Micro Air Vehicles

View full text Add to dashboard Cite

show abstract

“…The steady airfoil results are also compared with a small amplitude pitching NACA 0012 airfoil and the effect of pitching frequencies are investigated on the wake patterns and aerodynamics coefficients. 11,12 Rossi et al 9 and Durante et al 10 show that the classification of the wake structures is similarly visualized for Reynolds numbers ranging from 100 to 3000.…”

Section: Introductionmentioning

confidence: 98%

Vortex flow aerodynamics behind a symmetric airfoil at low angles of attack and Reynolds numbers

Kurtuluş

2021

International Journal of Micro Air Vehicles

Self Cite

View full text Add to dashboard Cite

The low Reynolds number aerodynamics is important to investigate for micro air vehicle applications. The current paper covers numerical simulations to present the downstream development of the wake patterns and detailed analysis of the vortices generated at the downstream of NACA 0012 airfoil around the critical angle of attack where the instantaneous vortex patterns are oscillatory and differ from the mean vortex pattern for low Reynolds numbers ranging from 1000 to 4000. The instantaneous and mean aerodynamic forces, pressure and skin friction coefficients, and vorticity values are compared in addition to the path of the vortex centers, their longitudinal and lateral spacings, Kármán spacing ratios, and distortion ratios at the wake of the airfoil in regard to the different Reynolds numbers investigated. The streamwise and crosswise velocities of the vortex cores and relative velocities at different transverse locations are also discussed and presented in detail. The correlations between different non-dimensional numbers (St, Re, Ro) are obtained at these low Reynolds numbers investigated.

show abstract

“…For this reason, many researchers use a numerical computational approach in flow analysis at ultra-low Re. Papers [7]- [9] compute flow simulation intensively for airfoil NACA 0012 at Re = 1000 by varying the angle of attack. Besides, Suzuki et al [10] simulate wing flapping using the lattice Boltzmann method (LBM) at Re = 100.…”

Section: Introductionmentioning

confidence: 99%

Convolutional Neural Networks-Based For Predicting Aerodynamic Coefficient Of Airfoils At Ultra-Low Reynolds Number

Kasman,

Zikri,

Fariduzzaman

et al. 2024

JOIV : Int. J. Inform. Visualization

View full text Add to dashboard Cite

Many applications, including airplane design, wind turbines, and heat transmission, use symmetric or asymmetric airfoils. Engineers employ these airfoil shapes to optimize performance and efficiency. Each airfoil has a unique set of aerodynamic coefficients that must be calculated to maximize the airfoil design. Engineers utilize numerous ways to calculate coefficients, such as lift and drag. One of the methods is the prediction method, which effectively reduces time and cost. This study's training dataset is obtained from particle-based numerical computation using the Lattice Boltzmann Method (LBM). Then, Convolutional Neural Networks (CNN) are used as a prediction method to get the aerodynamic coefficients of airfoils for lift and drag based on two different Reynolds numbers. In CNN, airfoil geometry representation is essential. The Signed Distance Function (SDF) was used to convert airfoil geometry into RGB pictures. On the other hand, the SDF method cannot explain different flow conditions; in this case, it is represented by the Reynolds number (Re). Therefore, we propose a Text-based Watermarking Method (TWM) to differentiate between Re = 500 and Re = 1000. Each airfoil representation was trained and tested to generate each prediction model using a modified LeNet-5. The computation results show that using CNN with TWM on SDF to define the Reynolds numbers could predict the lift and drag coefficients with varying angles of attack. Future research can focus on generalizations to different aerodynamic aspects and practical applications in complex scenarios.

show abstract

Unsteady aerodynamics of a pitching NACA 0012 airfoil at low Reynolds number

Cited by 16 publications

References 44 publications

Numerical study on aerodynamic characteristics of two-dimensional propulsive wing in cruise and hover

Numerical study on aerodynamic characteristics of two-dimensional propulsive wing in cruise and hover

Vortex flow aerodynamics behind a symmetric airfoil at low angles of attack and Reynolds numbers

Convolutional Neural Networks-Based For Predicting Aerodynamic Coefficient Of Airfoils At Ultra-Low Reynolds Number

Contact Info

Product

Resources

About