Önden Ve Yanal Rüzgar Şarti Altinda Zamana Bağli Sikiştirilamaz Ahmed Ci̇smi̇ni̇n Sayisal İncelenmesi̇

ZAFER, Baha; HASKARAMAN, Furkan

doi:10.17341/gazimmfd.300525

Cited by 3 publications

(3 citation statements)

References 19 publications

(18 reference statements)

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“…Flow characteristic was investigated changing the slant angle of Ahmed body [13]. The similar study related with crosswind and headwind of the Ahmed body was presented by Zafer and Haskaraman [14]. In this study, incompressible unsteady aerodynamic analysis was performed and compared with experimental study that is available in the literature.…”

Section: Introductionmentioning

confidence: 84%

Shape modification of Ahmed body to reduce drag coefficient and determination of turbulence model

Şumnu¹

2021

Ömer Halisdemir Üniversitesi Mühendislik Bilimleri Dergisi

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In this study, the aerodynamic analysis of Ahmed body which is generic automobile model is performed to determine convenient turbulence model and reduce drag coefficient by modifying shape of model. For this purpose, Computational Fluid Dynamics (CFD) analysis is carried out using different turbulence models that are Spalart-Allmaras, (Shear Stress Transport) SST k-, Standard k-, Realizable k-, (Re-Normalisation Group) RNG k- turbulence models. The results are compared with experimental data that is available in literature. The results show that RNG k- turbulence model gives superior performance when compared with other models. In order to reduce drag coefficient, the upper region of sides of model is rounded by applying fixed blend radius with 25 mm. The smooth surface can provide high performance in point of aerodynamics. CFD solution is then repeated for the modified model and the result show that drag coefficient value reduces about 6%. In addition, the second modification is performed by applying fixed blend radius with rounded both upper sides and rear underside of body and chamfer with 50 mm is also applied to rear sides of body. However, drag coefficient reduction level is approximately same with first modified model. The pressure coefficient contours and velocity streamlines are presented to show results for baseline and modified bodies.

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Section: Introductionmentioning

confidence: 84%

Shape modification of Ahmed body to reduce drag coefficient and determination of turbulence model

Şumnu¹

2021

Ömer Halisdemir Üniversitesi Mühendislik Bilimleri Dergisi

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“…The use of numerical analysis has become widespread, with high-speed computers and computeraided programs giving results close to the wind tunnel tests and the real studies. The most commonly used simplified vehicle model in the studies is the named Ahmed Body [5]. The Ahmed body is a model that was first experimentally analysed in 1984.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Effect of Side Mirror Forms on Ahmed Body with CFD Method

ARIKAN

Mutlu

2022

International Journal of Automotive Science and Technology

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The purpose of this study is to investigate the air resistance effect of different side mirror models on automobiles. The Ahmed Body model with 250 slant angle is taken as reference for use as automobile geometry. Ahmed body is a simplified geometry model used for aerodynamic analysis of land vehicles. Side mirror models with the same front projection area were modeled using Solidworks. CFD simulation was performed with ANSYS Fluent 19.2. Realizable k-ε model is used as turbulence model and pressure-based type is used as solver type. In this study, the mesh quality was checked in terms of skewness and showed conformity. CD value obtained by numerical analysis is compatible with experimental data. Then, a comparison was made by adding side mirrors to the Ahmed Body model. As a result of the analysis, the display of the velocity and pressure distribution caused by the change of form around the mirror models and total CD values were determined.

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“…As a passive flow control device added in front of the model, an aerodynamic improvement of 5.37% was achieved in the calculations conducted for four different Reynolds numbers between 173 000 and 346 000. Zafer and Haskaraman [19] carried out numerical computations for two different Ahmed models with slant angles of 25⁰ and 35⁰, using realizable k-epsilon turbulence model for 2.8x10 6 Reynolds number under front and side wind conditions. As a result, they determined that the width of the wake region, in which two asymmetrical vortices rotate in the opposite direction with each other in the wake of the vehicle, decreases by 60-70% due to the lateral wind and the leading wind conditions.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Aerodynamic Properties of Ahmed Body for Different Rear Slanted Surface Configurations

Kamaci¹,

Kaya²

2021

European Journal of Science and Technology

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The present study investigates aerodynamic characteristics of the Ahmed Body numerically, in case of that small rectangular flaps are attached to the leading edge of the rear slanted surface with a rear tilt angle of 25° and 35°. Numerical calculations have been conducted for three-dimensional, turbulent, steady, incompressible flow. Three different flap configurations have been considered: single flap, two flaps and three flaps. The commercial computational fluid dynamics solver ANSYS Fluent is used for the computations. To validate the numerical model, numerical solutions have been conducted with different combinations of turbulence model and wall functions, considering the values of drag coefficient obtained in a previous experimental work which studied slanted surface with flaps attached. Accordingly, k-epsilon Realizable turbulence model with Menter-Lechner wall function estimates the drag coefficient with an error of 8.8%. Results of the numerical calculations have shown that the best performance is obtained for the Ahmed model with 25° rear slant angle with three flaps mounted on the leading edge of the rear slanted surface, which provides a reduction in drag coefficient by 2.3%, compared to the model without flaps. Mechanisms for drag reduction are found to rely on generating a suction line along the leading edge of the rear slanted surface, which provides attached flow, although it is reversed. As for the 35° Ahmed model with flaps, on the other hand, no decrease in the drag coefficient is observed.

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Önden Ve Yanal Rüzgar Şarti Altinda Zamana Bağli Sikiştirilamaz Ahmed Ci̇smi̇ni̇n Sayisal İncelenmesi̇

Cited by 3 publications

References 19 publications

Shape modification of Ahmed body to reduce drag coefficient and determination of turbulence model

Shape modification of Ahmed body to reduce drag coefficient and determination of turbulence model

Investigation of the Effect of Side Mirror Forms on Ahmed Body with CFD Method

Numerical Investigation of Aerodynamic Properties of Ahmed Body for Different Rear Slanted Surface Configurations

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