Bir Otobüs Modeli Etrafındaki Akış Yapısının CFD Yöntemi İle İncelenmesi ve Sürükleme Kuvvetinin Pasif Akış Kontrol Yöntemi İle İyileştirilmesi

Bayındırlı, Cihan; Çelik, Mustafa; Demiralp, Mehmet

doi:10.2339/politeknik.403993

Cited by 6 publications

(7 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Shadmani et al [17] used an active flow control method to control the rear slant angle and the flow in the rear slanted section with the help of a plasma actuator in the 25⁰ Ahmed model, and the drag force decreased by about 2% at 20 m/s speed. Bayindirli et al [18] found that 13.38% of the drag force was caused by friction, while 86.42% of the drag force was caused by pressure, in a study they conducted on a vehicle model of Ahmed Body model with four different Reynolds numbers. 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.…”

Section: Introductionmentioning

confidence: 99%

“…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. Bayındırlı and Çelik [20] investigated the effects on friction force for five different Reynolds numbers with a spoiler model with one or two different sizes added to a vehicle model like Ahmed Body. They achieved aerodynamic improvement of 4.96% and 5.27%, respectively, for spoilers with different heights.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Kamaci¹,

Kaya²

2021

European Journal of Science and Technology

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

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

View full text Add to dashboard Cite

show abstract

“…The spoiler design could improve drag force by 17.6% [8]. [10]. The aim of this study is to determine of drag coefficient of a bus model experimentally and numerically.…”

Section: Introductionmentioning

confidence: 99%

“…At the a = 0 ° attack angle at L / D = 2 and 3 positions, significant decreases in drag force were obtained [9]. Bayındırlı et al (2018) determined the drag coefficient of 1/64 scaled bus model as 0.658 by numerically in Fluent®. The drag coefficient of bus model is decreased by passive flow control method [10].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Experimentally and Numerically Determination Of The Drag Coefficient Of A Bus Model

Bayındırlı¹,

Çelik

2018

International Journal of Automotive Engineering and Technologies

Self Cite

View full text Add to dashboard Cite

In this study, the drag coefficient of a 1/33 scaled bus model was determined by experimentally in wind tunnel and numerically in Fluent®. The tests were performed at 6 different free flow velocities and between the range of 382 866-792 900 Reynolds numbers and 13.54m/s-28.05m/s speeds. The three similarity conditions were provided in tests. The flow analyses were conducted in 1/40 scaled wind tunnel as experimentally using Reynolds independent. The aerodynamic drag coefficient (CD) of the bus model was calculated as 0.633 in wind tunnel. The experimental results of bus model are verificated by numerical flow analysis in Fluent® program. According to numerical results, the drag coefficient of bus model is calculated as 0.645 with 1.81% error margin.

show abstract

Parametric, response surface, and adjoint optimizations of the underbody diffuser of a generic ground vehicle

Akar

Baş

2023

Numerical Methods in Fluids

View full text Add to dashboard Cite

SUMMARYIt is a known fact in the literature that diffusers improve vehicle aerodynamics in terms of lift and drag forces. However, their effectiveness and efficiencies are quite sensitive to the design parameters. In this article, the underbody diffuser of a generic ground vehicle, Ahmed body, was optimized via CFD software of Ansys Fluent, step by step with parametric, response surface, and discrete adjoint techniques, respectively. Three numerical models (parametric, response surface, and adjoint models) have been created considering optimum force output for each optimization method, and qualitative and quantitative assessments were made on these models to compare flow characteristics and force coefficients with the base model. As a result, force coefficients are lower by 48.6, 49.3, and 52.8 counts for CD, 499.6, 547.4, and 528.2 counts for CL at parametric, response surface, and adjoint optimization phases compared with the base model, respectively. It is observed that diffusers help to improve flow transition and relief underbody and reduce the airflow over the upperbody zone by directing it to the underbody. However, detailed quantitative assessments show that it comes out that the contribution of the underbody to total CD may increase due to lower pressure distribution diffuser upsweep caused by higher mass flow beneath the model. These results demonstrate the importance of effective utilization and further controlling of underbody flow when using an underbody diffuser.

show abstract

Bir Otobüs Modeli Etrafındaki Akış Yapısının CFD Yöntemi İle İncelenmesi ve Sürükleme Kuvvetinin Pasif Akış Kontrol Yöntemi İle İyileştirilmesi

Cited by 6 publications

References 22 publications

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

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

The Experimentally and Numerically Determination Of The Drag Coefficient Of A Bus Model

Parametric, response surface, and adjoint optimizations of the underbody diffuser of a generic ground vehicle

Contact Info

Product

Resources

About