Control of Vortex-Induced Turbulent Flow by Curved Perforated Plate

Year 2020, Volume: 35 Issue: 4, 1021 - 1030, 31.12.2020

Göktürk Memduh Özkan Tahir Durhasan Engin Pınar

https://doi.org/10.21605/cukurovaummfd.869170

Abstract

In this study, the control of the vortex-induced turbulent flow in the wake of a circular cylinder was investigated using curved perforated plate (control element) having various and partial porosities. PIV measurements were performed for the considered parameter ranges, Reynolds shear stresses were calculated in the flow field and the contour distributions of the bare cylinder and controlled cases were compared quantitatively. According to the results, it was understood that the Reynolds numbers had identical effects on the flow control. However, it was observed that the shear stresses in the cylinder wake decreased for all examined cases of porosity and arc angle. It has been revealed that the maximum value of Reynolds shear stress is decreased by 96% compared with the bare cylinder and the unsteady flow in the cylinder wake is completely controlled at 120o≤ α ≤180o for β = 0.5 and β = 0.6.

Keywords

Flow control, Unsteady flow, Vortex shedding, Bluff body, PIV

Kavisli Delikli Plaka ile Girdap Kaynaklı Türbülanslı Akışın Kontrolü

Abstract

Bu çalışmada, dairesel bir silindir art izinde oluşan girdap kaynaklı türbülanslı akışın, farklı ve kısmi geçirgenlik oranlarına sahip kavisli delikli plaka (kontrol elemanı) ile kontrolü incelenmiştir. Ele alınan parametre aralıklarında PIV ile hız ölçümleri yapılmış, akış alanında Reynolds kayma gerilmeleri hesaplanmış ve kontrol durumu ile yalın silindir durumunun kontur dağılımları nicel olarak karşılaştırılmıştır. Elde edilen sonuçlara göre, ele alınan Reynolds sayılarının akış kontrolüne benzer oranda etki ettiği anlaşılmıştır. Bununla birlikte, incelenen tüm geçirgenlik oranları ve yay açıları için silindir art izinde oluşan kayma gerilmelerinin azaldığı görülmüştür. 120o≤ α ≤180o yay açılarında ve β=0,5 ve β =0,6 geçirgenlik oranlarında, yalın silindire kıyasla maksimum Reynolds kayma gerilmelerinin %96’ya kadar düştüğü ve silindir art izindeki daimi olmayan akışın tamamen kontrol edildiği ortaya çıkarılmıştır.

Keywords

Akış kontrol, Daimi olmayan akış, Girdap kopması, Küt cisim, PIV

References

• 1. Unal, M.F., Rockwell, D., 1988. On Vortex Formation from a Cylinder. Part 2. Control by Splitter-plate Interference. Journal of Fluid Mechanics, 190, 513-529.
• 2. Kwon, K., Choi, H., 1996. Control of Laminar Vortex Shedding Behind a Circular Cylinder Using Splitter Plates. Physics of Fluids, 8, 479–486.
• 3. Mittal, S., Raghuvanshi, A., 2001. Control of Vortex Shedding Behind Circular Cylinder for Flows at Low Reynolds Numbers. Int J Num Meth Fl, 35, 421–447.
• 4. Akilli, H., Sahin, B., Tumen, N.F., 2005. Suppression of Vortex Shedding of Circular Cylinder in Shallow Water by a Splitter Plate. Flow Meas. Instrum. 16, 211–219.
• 5. Wang, J.J., Zhang, P.F., Lu, S.F., Wu, K., 2006. Drag Reduction of a Circular Cylinder Using an Upstream Rod. Flow Turbul Combust, 76, 83–101.
• 6. Baek, H., Karniadakis, G.E., 2009. Suppressing Vortex-induced Vibrations Via Passive Means. J Fluid Struct, 25, 848–866.
• 7. Dehkordi, B.G., Jafari, H.H., 2010. On the Suppression of Vortex Shedding from Circular Cylinders Using Detached Short Splitter-plates. J Fluid Eng-T ASME, 132, 044501.
• 8. Yucel, S.B., Cetiner, O., Unal, M.F., 2010. Interaction of Circular Cylinder Wake with a Short Asymmetrically Located Downstream Plate. Exp Fluids, 49, 241–255.
• 9. Zdravkovich, M.,M., 1981. Review and Classification of Various Aerodynamic and Hydrodynamic Means for Suppressing Vortex Shedding. Journal of Wind Engineering and Industrial Aerodynamics, 7(2), 145-189.
• 10. Akıllı, H., Karakus, C., Akar, A., Sahın, B., Tumen, N.F., 2008. Control of Vortex Shedding of Circular Cylinder in Shallow Water Flow Using an Attached Splitter Plate. J Fluid Eng-T ASME, 130, 041401.
• 11. Ozkan, G.M., Oruc, V., Akilli, H., Sahin, B., 2012. Flow Around a Cylinder Surrounded by a Permeable Cylinder in Shallow Water. Exp Fluids, 53, 1751–1763.
• 12. Ozkan, G.M., Firat, E., Akilli, H., 2017. Passive Flow Control in the Near Wake of a Circular Cylinder Using Attached Permeable and Inclined Short Plates. Ocean Engineering, 134, 35-49.
• 13. Pinar, E., Ozkan, G.M.,, Durhasan, T., Akilli, H., Sahin, B., 2015. Flow Structure Around Perforated Cylinders in Shallow Water. 55, 52-63.
• 14. Durhasan, T., Aksoy, M.M., Pinar, E., Ozkan, G.M., Akilli, H., Sahin, B., 2016. Vortex Street Suppression of a Circular Cylinder Using Perforated Semi-circular Fairing in Shallow Water, Experimental Thermal and Fluid Science, 79, 101-110.
• 15. 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.
• 16. 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.
• 17. Adrian, R.J., Westerweel, J., 2011. Particle Image Velocimetry, Cambridge Univetsity Press, New York, USA, 350.
• 18. Adrian, R.J., Westerweel, J., 2011. Particle Image Velocimetry, Cambridge Univetsity Press, New York, USA, 34-35.
• 19. Aljure, D.E., Rodriguez, I., Lehmkuhl, Perez- Segarra, Oliva, A., 2015. Influence of Rotation on the Flow Over a Cylinder at Re=5000. Int. J. Heat Fluid Flow 55, 76–90.