Abstract
The drag coefficients of freestream-aligned circular cylinders of fineness ratios of 0.75–2.0 were investigated with a magnetic suspension and balance system (MSBS). The objective was to find the critical geometry, that is, the fineness ratio at which the drag coefficient becomes the local maximum within this ratio range. The experiments were conducted using the 1-m MSBS at the low turbulence wind tunnel at the Institute of Fluid Science, Tohoku University. The drag and base pressure coefficients of various cylinders were measured. The freestream velocity was varied to produce flows with Reynolds numbers ranging from \(0.6\times 10^5\) to \(1.0\times 10^5\). The drag coefficient monotonically decreases as the fineness ratio increases and no critical geometry or local maximum of the drag coefficient is found in the range we investigated. The base pressure coefficient decreases as the fineness ratio increases. The temporal fluctuations of the base pressure of the models with fineness ratios of 0.75, 1.0, and 1.2 are approximately twice as large as that of the model with a ratio of 2.0. The relationship between the fineness ratio and the drag coefficient is similar to that between the fineness ratio and the base pressure coefficient, similar to the findings of previous studies of two-dimensional bodies.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bearman P, Trueman D (1972) An investigation of the flow around rectangular cylinders. Aeronaut Q 23(3):229–237
Bergh H, Tijdeman H (1965) Theoretical and experimental results for the dynamic response of pressure measuring systems. TR F.238, Nationaal Lucht-en Ruimtevaartlaboratorium
Britcher CP, Alcorn CW (1991) Interference-free measurements of the subsonic aerodynamics of slanted-base ogive cylinders. AIAA J 29(4):520–525
Eiffel G (1907) Recherches expérimentales sur la résistance de l’Air exécutées à la tour eiffel. L Maretheux, Paris, France (in French)
GtbJCH Eiffel (1913) The resistance of the air and aviation. Constable Co, Houghton, Mifflin & Co, London
Elger DF, Roberson JA (2013) Engineering fluid mechanics. Wiley, Hoboken
Ericsson L, Reding J (1983) Review of support interference in dynamic tests. AIAA J 21(12):1652–1666
Fukata K (2017) Development and demonstration of base-pressure telemetry system for magnetic suspension and balance system (in Japanese). Master’s thesis, Tohoku University
Higuchi H, Sawada H, Kato H (2008) Sting-free measurements on a magnetically supported right circular cylinder aligned with the free stream. J Fluid Mech 596:49–72
Hoerner SF (1965) Fluid-dynamic drag: practical information on aerodynamic drag and hydrodynamic resistance, 2nd edn. Albuquerque
Maskell E (1965) A theory of the blockage effects on bluff bodies and stalled wings in a closed wind tunnel. R&M 3400, Aeronautical Research Council, London (United Kingdom)
Nakaguchi H (1968) An experimental study on aerodynamic drag of rectangular cylinders. J Jpn Aeronaut Space Sci (in Jpn) 16:1–5
Nakaguchi H (1978) Recent Japanese research on three-dimensional bluff-body flows relevant to road-vehicle aerodynamics. In: Sovran G et al (eds) Aerodynamic drag mechanisms of bluff bodies and road vehicles. Plenum Press, New York, pp 227–246
Ohya Y (1994) Note on a discontinuous change in wake pattern for a rectangular cylinder. J Fluids Struct 8(3):325–330
Prosser DT, Smith MJ (2015) Aerodynamics of finite cylinders in quasi-steady flow. In: AIAA2015-1931
Roberson JA, Lin CY, Rutherford SG, Stine MD (1972) Turbulence effects on drag of sharp-edged bodies. J Hydraul Div 98(7):1187–1203
Roos FWFW, Willmarth WW (1971) Some experimental results on sphere and disk drag. AIAA J 9(2):285–291. https://doi.org/10.2514/3.6164
Sawada H, Obayashi S (2015) A new 1-m magnetic suspension and balance system for the low turbulence wind tunnel at IFS. In: Proceedings of thirteenth international conference on flow dynamics
Sawada H, Suda S (2011) Study on aerodynamic force acting on a sphere with and without boundary layer trips around the critical reynolds number with a magnetic suspension and balance system. Exp Fluids 50(2):271–284. https://doi.org/10.1007/s00348-010-0920-2
Acknowledgements
This work was supported by JSPS KAKENHI Grant number 16H04582.
Author information
Authors and Affiliations
Corresponding author
Appendix: Effects of yaw (pitch) angle on the drag coefficients
Appendix: Effects of yaw (pitch) angle on the drag coefficients
The effects of yaw angle, which is equivalent to the pitch angle, on the drag and base pressure coefficients were investigated in the same system in the range \(-1.5<\theta <1.5\) (\(^\circ\)). The results of multiple runs are shown in Fig. 19. Clear trends are not found for 0.75 \(<L/D<\) 1.2, and weak parabolic variation is found for \(L/D=2.0\). The fluctuation (rms) of yaw angle, however, is less than 0.6\(^\circ\) in this experiment, as noted before, and this fluctuation does not seem to affect the drag and base pressure coefficients, even in the case of \(L/D=2.0\), for the objectives of this study.
Effect of yaw angle on uncorrected drag and base pressure coefficients
Rights and permissions
About this article
Cite this article
Nonomura, T., Sato, K., Fukata, K. et al. Effect of fineness ratios of 0.75–2.0 on aerodynamic drag of freestream-aligned circular cylinders measured using a magnetic suspension and balance system. Exp Fluids 59, 77 (2018). https://doi.org/10.1007/s00348-018-2531-2
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/s00348-018-2531-2