Reynolds sayısı Bağımsızlık kullanma A Otobüs Modelinin sürükleyin Katsayısı Tayini

Bu tam ölçekli rüzgar tünellerinin araçların sürükleme katsayıları belirlemek için büyük bir zaman ve maliyet gereklidir. Bu çalışmada, künt otobüs modelinin sürtünme katsayısı Reynolds sayısı bağımsızlığı kullanılarak tespit edilmeye çalışılmıştır. Serbest akış hızına sahip olan bir düşük hız rüzgar tüneli 28 m / s olup, yüksek ve geniş bir dikdörtgen şeklinde bir enine kesite sahiptir, deneylerinde kullanılmıştır. Otobüs modeli etrafında akış rüzgar tüneli koşullarında ANSYS CFX ile simüle edildi. Sonuç olarak, otobüs modelinin aerodinamik sürtünme katsayısı sırasıyla Reynolds sayısı 57000. Bu künt araçların sürtünme katsayısı kullanarak belirlemek olabilir tespit edildikten sonra CFX sonuçlarına ve deneye göre 0,66 ve 0.65 olarak tespit edildi düşük hız rüzgar tüneli ve Reynolds sayısı bağımsızlığı.

Anahtar Kelimeler:

Sürükle katsayısı, Reynolds sayısı, araç aerodinamik, sürükleme kuvveti, performans

Drag Coefficient Determination Of A Bus Model Using Reynolds Number Independence

It is needed to great time and cost to determine drag coefficients of vehicles with full-scale wind tunnels. In this study, drag coefficient of a blunt bus model was tried to be determined using Reynolds number independence. A low speed wind tunnel having a free flow velocity is 28 m/s and has a rectangular cross section of high and wide, was used in experiments. The flow around the bus model was simulated with ANSYS CFX at wind tunnel conditions. As a result, aerodynamic drag coefficient of the bus model was determined as 0,66 and 0,65 according to results of CFX and experiment respectively after Reynolds number 57000. It is determined that the drag coefficient of the blunt vehicles can be determine by using low speed wind tunnel and Reynolds number independence.

Keywords:

Drag coefficient, Reynolds number, vehicle aerodynamic, drag force, performance,

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İçingür, Y., Solmaz, H., “Determination of drag coefficients of various automobile models in a low speed wind tunnel”, Journal of the faculty of engineering and architecture of Gazi University, 2, 60-62, 2011.
Hucho, W. H., “Aerodynamics Of Road Vehicles”, Butterworth, London, 106-150, 298-410 (1998).
Gürlek, C., “Study of the flow around a bus”, PhD Thesis, Çukurova University Graduate School of Natural and Applied Sciences, Adana, 119-122, 2008.
Solmaz, H., İçingür, Y., “Importance and determination of lift coefficient for road vehicles”, Journal of Polytechnic, 13, 3, 203-208, 2010.
Milliken, W.F., Milliken, D.L., “Race Car Vehicle Dynamics”,Society of Automotive Engineers International, Warrendale, 83-110, 1995.
Sumantran, V., Sovran, G., “Vehicle Aerodynamics”, Society of Automotive Engineers International, Warrendale, 483-531, 1996.
Barnard, B.H., “Road Vehicle Aerodynamic Design”, Longman, London, 1-20, 1996.
Kavadar, G., “Design and protoyping of a mechatronic system as a drag reduction device for buses”, MSc Thesis, İzmir Institute of Technology, İzmir, 80-86, 2006.
Wiedemann J., Ewald, B., Turbulance maniplation to increase effective Reynolds numbers in vehicle aerodynamics. AIAA J. 27, 763-69, 1989.
Chuan, F.J., Tao, Y., “Low speed pressurized wind tunnel at home which is building”, Journal of Experiments in Fluid Mechanics, 19, 3, 1-6, 2005.
White, M.F., “Akışkanlar Mekaniği”, McGraw Hill, İstanbul, 210-220, 2004.
Çengel, Y.A., Cimbala, J.M., “Akışkanlar Mekaniği” McGraw Hill, İzmir, 299-300, 2008.
Solmaz, H., “Determination drag coefficient of different vehicle models in a wind tunnel”, MSc Thesis, Gazi University Institute of Science and Technology, Ankara, 10-50, 2010.
Houghton, E. L. And Carpenter, P. W., “Aerodynamics For Engineering Students”, Butterwworths, London, 464-465, 2003.
Aka, H., “Otomobillerin aerodinamik karakteristiğinin bir rüzgar tünelinde incelenmesi”, MSc Thesis, Gazi University Institute of Science and Technology, Ankara, 67-69, 2003.
Gao Feng, Xie Jinfa, Wei Daofu, "Numerical simulation 3-D turbulent flow around the sedan", Chinese Journal of Mechanical Engineering, 36, 6, 48-51, 2000.
Gu Zhengqi, Jing Lehua, WU Jun, "The Numerical Analysis and computer simulation on automobile flowfield", Journal of Acta Aerodynamica Sinica, 18, 2, 188-192, 2000.
Lanfang Jiang, Hong Liu, Guozhong Chai, Guangnan Jiang, Weiming Lin, “Effect of Automotive Headlamp Modeling on Automotive Aerodynamic Drag”, Proceeding of CAID&CD'2008, Kunming, 588-593, November 2008