Dairesel Silindir Çevresindeki Pasif Akış Kontrolünün Sayısal İncelenmesi

Yıl 2023, Cilt: 38 Sayı: 1, 243 - 252, 30.03.2023

Tural Tunay

https://doi.org/10.21605/cukurovaumfd.1273807

Öz

Mevcut çalışmada, delikli bir silindirin, duvara monte edilmiş dairesel bir silindir etrafındaki pasif akış kontrolü üzerindeki etkileri incelenmiştir. Delikli silindir, tek dairesel silindirin dışına eş merkezli olarak yerleştirilmiştir. Akış alanının çözümlenmesinde büyük girdap simülasyonu kullanıldı. Çalışma hem tekil silindir üzerine etkiyen sürükleme kuvveti katsayısının azaltılmasını hem de aşağı akış bölgesinde girdap kopmalarından kaynaklanan ve silindir üzerine etkiyen değişken kuvvetlerin kontrol edilmesini amaçlamıştır. Sonuçlar, tekil silindirin aşağı akış girdap bölgesindeki akış yapılarının delikli silindirin eş merkezli olarak yerleştirilmesinden sonra önemli ölçüde değiştiğini ortaya koymuştur. Örnek olarak, von Karman girdap yapıları artık oluşmamıştır, ve aşağı akış girdap bölgesinde türbülans kinetik enerji miktarı önemli ölçüde azalmıştır. Tek silindirin zaman ortalamalı sürtünme katsayısı değeri %69 oranında azalmıştır. Ayrıca, tek silindirin zamana bağlı kaldırma kuvveti katsayısının maksimum büyüklüğü, delikli silindir tek silindirin dışına eşmerkezli olarak yerleştirildikten sonra sekiz kat azalmıştır.

Anahtar Kelimeler

Silindir, Sürtünme direnci, Akış kontrolü, BGS, Girdap kopması

Numerical Investigation of the Passive Flow Control Around a Circular Cylinder

Öz

The effects of a perforated cylinder on the passive flow control around a circular cylinder mounted on a wall were investigated. The perforated cylinder was placed outside of the single circular cylinder concentrically. The large-eddy simulation was used to resolve the flow field. The study was aimed at both reducing the drag coefficient of the single cylinder and controlling the fluctuating forces acting on the single cylinder caused by vortex shedding in the downstream wake. The results showed that the structure of the downstream wake flow of the single cylinder changed significantly after placing the perforated cylinder. For example, von Karman vortices disappeared, and the maximum magnitude of turbulent kinetic energy, TKE, in the downstream wake was reduced. The time-averaged drag coefficient of the single cylinder was decreased by 69%. In addition, the maximum value of the lift coefficient of the single cylinder was reduced by eight times when the perforated cylinder was placed outside the single cylinder.

Anahtar Kelimeler

Cylinder, Drag, Flow control, LES, Vortex shedding

Kaynakça

• 1. Ma, L.Q., Feng, L.H., 2019. Vortex Formation and Evolution for Flow Over a Circular Cylinder Excited by Symmetric Synthetic Jets, Experimental Thermal and Fluid Science, 104, 89–104. doi:10.1016/j.expthermflusci.2019.02. 008.
• 2. Zhang, X., Choi, K.S., Huang, Y., Li, H.X., 2019. Flow Control Over a Circular Cylinder Using Virtual Moving Surface Boundary Layer Control, Experiments In Fluids, 60:104. doi:10.1007/s00348-019-2745-y.
• 3. Gao, D.L., Chen, G.B., Huang, Y.W., Chen, W.-L., Li, H., 2020. Flow Characteristics of a Fixed Circular Cylinder with an Upstream Splitter Plate: on the Plate-Length Sensitivity. Experimental Thermal and Fluid Science, 117, 110135.
• 4. Choi, H., Jeon, W.P., Kim, J., 2008. Control of Flow Over a Bluff Body, Annu. Rev. Fluid Mech., 40, 113–39. doi:10.1146/annurev.fluid. 39.050905.110149.
• 5. Tiainen, J., Grönman, A., Jaatinen-Värri, A., Backman, J., 2018. Flow Control Methods and Their Applicability in Low-Reynolds-Number Centrifugal Compressors - A Review, Int. J. Turbomach. Propuls. Power, 2018, 3, 2. doi:10.3390/ijtpp3010002.
• 6. Paul, A.R., Joshi, S., Jindal, A., Maurya, S.P., Jain, A., 2013. Experimental Studies of Active and Passive Flow Control Techniques Applied in a Twin Air-Intake, The Scientific World Journal, 2013(523759), 8. doi:10.1155/2013/ 523759.
• 7. Ünal, U.O., Atlar, M., 2010. An Experimental Investigation into the Effect of Vortex Generators on the Near-Wake Flow of a Circular Cylinder, Exp. Fluids 48, 1059–1079. doi:10.1007/s00348-009-0791-6.
• 8. Chen, T., Jiang, X., Wang, H., Li, Q., Li, M., Wu, Z., 2021. Investigation of Leading-Edge Slat On Aerodynamic Performance of Wind Turbine Blade, Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 235(8):1329-1343. doi:10.1177/0954406220941883.
• 9. Bari, S., Saad, I., 2013. CFD Modelling of the Effect of Guide Vane Swirl and Tumble Device to Generate Better In-Cylinder Air Flow in a CI Engine Fuelled by Biodiesel, Computers & fluids, 84, 262-269. doi:10.1016/j.compfluid.2013.06.011.
• 10. Gao, D.L., Chen, W.L., Li, H., Hu, H., 2017. Flow Around a Circular Cylinder with Slit, Experimental Thermal and Fluid Science, 82, 287–301. doi:10.1016/j.expthermflusci.2016. 11.025.
• 11. Neelamani, S., Koether, G., Schuttrumpf, H., Muttray, M., Oumeraci, H., 2000. Wave Forces on, and Water-Surface Fluctuations Around a Vertical Cylinder Encircled by a Perforated Square Caisson, Ocean Engineering, 27, 775–800.
• 12. Acharya, S., Dash, S.K., 2018. Natural Convection Heat Transfer from Perforated Hollow Cylinder with Inline and Staggered Holes, Journal of Heat Transfer, 140, 032501-1. https://doi.org/10.1115/1.4037875.
• 13. Liu, J., Lin, G., Li, J., 2012. Short-Crested Waves Interaction with a Concentric Cylindrical Structure with Double-Layered Perforated Walls, Ocean Engineering, 40, 76–90.
• 14. Vijayalakshmia, K., Neelamanib, S., Sundaravadivelua, R., Murali, K., 2007. Wave Runup on a Concentric Twin Perforated Circular Cylinder, Ocean Engineering, 34, 327–336. doi:10.1016/j.oceaneng.2005.11.021.
• 15. Sun, C., Azmi, A.M., Zhu, H., Zhou, T., Cheng, L., 2021. Experimental Study on Wake Structures of a Circular Cylinder Enclosed in a Screen Shroud Using PIV, Ocean Engineering, 230, 109056. doi:10.1016/j.oceaneng.2021. 109056.
• 16. Durhasan, T., Pinar, E., Ozkan, G.M., Aksoy, M.M., Akilli, H., Sahin, B., 2018. PIV Measurement Downstream of Perforated Cylinder in Deep Water, European Journal of Mechanics/B Fluids, 72, 225–234.
• 17. Durhasan, T., Pinar, E., Ozkan, G.M., Akilli, H., Sahin, B., 2019. The Effect of Shroud on Vortex Shedding Mechanism of Cylinder, Applied Ocean Research, 84, 51–61.
• 18. Parnaudeau, P., Carlier, J., Heitz, D., Lamballais, E., 2008. Experimental and Numerical Studies of the Flow Over a Circular Cylinder at Reynolds Number 3900, Physics of Fluids, 20(8), 085101.