Numerical Analysis of NACA 6409 and Eppler 423 Airfoils

Seyhun Durmuş; Aytekin Ulutaş

Makale detayları

Numerical Analysis of NACA 6409 and Eppler 423 Airfoils

Yazarlar:

Seyhun Durmuş | Aytekin Ulutaş

Yayıncı:

Gazi University

Ana Başlıklar:

Mühendislik

Dergi:

Politeknik Dergisi Vol.26 Issue 1, pp.39-47

Belge Tipi:

Makale

Yayın Tarihi:

3/2023

Belge Dili:

İngilizce

Document ID (Org No.):

2001285725

pISSN:

2147-9429

Anahtar kelimeler:

Özet:

 The present study aims to numerically examine two commonly used airfoils that provide high lift at low Reynolds numbers, using various turbulence models with the commercial code ANSYS Fluent 19. Eppler 423 airfoil is widely used in wind turbine blades, wings of gliders and RC airplanes designed for sport flying and competitions thanks to high lift capability. NACA 6409 airfoil is seen in free-flight model planes. In literature review, it has been found that k-ω SST, k-kl-ω and - transition models have a good prediction in Cl-Cd estimation of drag bucket region, transition flow regime, and laminar separation point. In addition to RANS models, laminar model was also investigated. In order to ensure the accuracy and precision of numerical investigations; the grid sensitivity study and near wall model were used. The method of decomposition of flow direction vector procedure has been used to provide the advantage of simulating all angle of attacks using only a single mesh. The lift coefficient curves and polar diagrams were formed from the angle of attack of -4 degree up to the stall. Experimental data, XFoil analysis data and numerical analysis data were evaluated in terms of best glide ratio-ClCdmax and minimum sink-Cl1.5Cdmax criteria. As expected, at high angle of attack, the transition ramp on the upper surface moves forward and the pressure gradient became more adverse. The results showed that fine mesh gives better results than other mesh sizes and transitional γ-Reθ SST model was successful in modelling the transition event than other turbulence models.

 The present study aims to numerically examine two commonly used airfoils that provide high lift at low Reynolds numbers, using various turbulence models with the commercial code ANSYS Fluent 19. Eppler 423 airfoil is widely used in wind turbine blades, wings of gliders and RC airplanes designed for sport flying and competitions thanks to high lift capability. NACA 6409 airfoil is seen in free-flight model planes. In literature review, it has been found that k-ω SST, k-kl-ω and - transition models have a good prediction in Cl-Cd estimation of drag bucket region, transition flow regime, and laminar separation point. In addition to RANS models, laminar model was also investigated. In order to ensure the accuracy and precision of numerical investigations; the grid sensitivity study and near wall model were used. The method of decomposition of flow direction vector procedure has been used to provide the advantage of simulating all angle of attacks using only a single mesh. The lift coefficient curves and polar diagrams were formed from the angle of attack of -4 degree up to the stall. Experimental data, XFoil analysis data and numerical analysis data were evaluated in terms of best glide ratio-ClCdmax and minimum sink-Cl1.5Cdmax criteria. As expected, at high angle of attack, the transition ramp on the upper surface moves forward and the pressure gradient became more adverse. The results showed that fine mesh gives better results than other mesh sizes and transitional γ-Reθ SST model was successful in modelling the transition event than other turbulence models.

 The present study aims to numerically examine two commonly used airfoils that provide high lift at low Reynolds numbers, using various turbulence models with the commercial code ANSYS Fluent 19. Eppler 423 airfoil is widely used in wind turbine blades, wings of gliders and RC airplanes designed for sport flying and competitions thanks to high lift capability. NACA 6409 airfoil is seen in free-flight model planes. In literature review, it has been found that k-ω SST, k-kl-ω and - transition models have a good prediction in Cl-Cd estimation of drag bucket region, transition flow regime, and laminar separation point. In addition to RANS models, laminar model was also investigated. In order to ensure the accuracy and precision of numerical investigations; the grid sensitivity study and near wall model were used. The method of decomposition of flow direction vector procedure has been used to provide the advantage of simulating all angle of attacks using only a single mesh. The lift coefficient curves and polar diagrams were formed from the angle of attack of -4 degree up to the stall. Experimental data, XFoil analysis data and numerical analysis data were evaluated in terms of best glide ratio-ClCdmax and minimum sink-Cl1.5Cdmax criteria. As expected, at high angle of attack, the transition ramp on the upper surface moves forward and the pressure gradient became more adverse. The results showed that fine mesh gives better results than other mesh sizes and transitional γ-Reθ SST model was successful in modelling the transition event than other turbulence models.

 Bu çalışma, düşük Reynolds sayılarında yüksek taşıma sağlayan yaygın olarak kullanılan iki kanat profilini, ticari kod ANSYS Fluent 19 ile çeşitli türbülans modelleri kullanarak sayısal olarak incelemeyi amaçlamaktadır. Eppler 423 kanat profilini sayısal olarak analiz etmektir. Eppler 423 kanat profili, yüksek taşıma kabiliyeti nedeniyle rüzgâr türbini kanatlarında, çapraz akış fanlarında, planörlerin ana kanatlarında, sportif uçuşlar ve yarışmalar için tasarlanmış radyo kontrollü uçaklarda yaygın kullanılan bir profildir. NACA 6409 kanat profili, serbest uçuş model uçaklarda kullanılır. Literatür taramasında k-ω SST, k-kl-ω ve - geçiş modellerinin sürükleme poler bölgesinin Cl-Cd tahminlerinde, geçiş bölgesi akış rejiminde ve laminer ayrılma noktasında iyi bir tahmin yeteneğine sahip olduğu görülmüştür. Çalışmada RANS modellere ek olarak laminer model de incelenmiştir. Sayısal çözümlerin doğruluğunu ve hassasiyetini sağlamak için kafes duyarlılık çalışması ve yakın duvar modeli kullanılmıştır. Akış yönü vektörü ayrışması tekniği, sadece tek bir ağ kullanarak tüm hücum açılarını simüle etme avantajını sağlamak için kullanılmıştır. Taşıma katsayısı eğrileri ve kutup şemaları, -4 derece hücum açısından başlanarak stol hücum açısına kadar oluşturulmuştur. Deneysel veriler, XFoil analiz verileri ve nümerik analiz verileri en iyi süzülme oranı- ClCdmaks ve minimum çöküş- Cl1.5Cdmaks kriterleri açısından değerlendirilmiştir. Beklendiği gibi, yüksek hücum açısında, üst yüzeydeki geçiş rampası ileri doğru hareket eder ve üst yüzeydeki basınç gradyanı negatif hale gelmiştir. Sonuçlar, ince ağın diğer ağ boyutlarına göre daha iyi sonuçlar verdiği; γ-Reθ SST modelinin diğer türbülans modellerine göre geçiş olayını modellemede daha başarılı olduğunu göstermiştir.

Makale detayları

Numerical Analysis of NACA 6409 and Eppler 423 Airfoils

Yazarlar:

Seyhun Durmuş | Aytekin Ulutaş

Yayıncı:

Gazi University

Ana Başlıklar:

Mühendislik

Dergi:

Politeknik Dergisi Vol.26 Issue 1, pp.39-47

Belge Tipi:

Makale

Yayın Tarihi:

3/2023

Belge Dili:

İngilizce

Document ID (Org No.):

2001285725

pISSN:

2147-9429

γ-Reθ SST Turbulence Model

NACA 6409

Epler 423

RANS

CFD

RANS

γ-Reθ SST Türbülans Modeli

NACA 6409

Epler 423

RANS

HAD

Sayı

Makale detayları

Yazarlar: Seyhun Durmuş | Aytekin Ulutaş

Yayıncı: Gazi University

Ana Başlıklar: Mühendislik

Dergi: Politeknik Dergisi Vol.26 Issue 1, pp.39-47

Belge Tipi: Makale

Yayın Tarihi: 3/2023

Belge Dili: İngilizce

Document ID (Org No.): 2001285725

pISSN: 2147-9429

Sayı

Yazarlar:

Seyhun Durmuş | Aytekin Ulutaş

Yayıncı:

Gazi University

Ana Başlıklar:

Mühendislik

Dergi:

Politeknik Dergisi Vol.26 Issue 1, pp.39-47

Belge Tipi:

Makale

Yayın Tarihi:

3/2023

Belge Dili:

İngilizce

Document ID (Org No.):

2001285725

pISSN:

2147-9429