Numerical and Experimental Analysis of Turbulent Fluid Flow around Latest Generation Cycling Frame

Numerical and Experimental Analysis of Turbulent Fluid Flow around Latest Generation Cycling Frame

M. Castellini M. Barbanera M. Scungio F. Arpino

Department of Economics, Engineering, Society and Business, University of Tuscia, Italy

Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Italy

Available online: 
| Citation



Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical analysis and data structures to analyse and solve problems that involve fluid flows. Today, CFD plays a decisive role in the cycling industry, which affects not only bicycle manufacturers, but also, above all, bicycle component suppliers. In fact, aerodynamic research takes place not only in the cyclist’s best riding position, but also in the design of the components and frames that make up a racing bike. The frame design is essential both for its ability to oppose the aerodynamic resistance and to adapt the cyclist to the best geometry. Among the multiple outlets of the method, the simulation of external aerodynamic flows shows a fundamental importance for the understanding of the role played by the design of the bicycle. Once a numerical analysis was set correctly, it was then possible to predict with good reliability the fluid dynamic behaviour of an entire structure without the need to use experimental approaches every time. The main aim of this study consists of the validation of a numerical model through experiments conducted on a scale model of a latest generation cycling frame in an open chamber wind tunnel by means of the Particle Image Velocimetry (PIV) technique. In particular, the scale model used was investigated in two specific regions. The experimental data were compared to numerical results obtained employing  turbulence model, and the validated numerical tool was subsequently applied to estimate the drag coefficient of two different types of handlebars (aerodynamic and standard versions). The standard cylindrical handlebar folds were replaced by products made of composite and with the most innovative and modern shapes, able to significantly reduce the aerodynamic resistance values. Indeed, in the design phase, the measurement of the drag coefficient is a fundamental procedure. As expected, the presence of aerodynamic profiles generated a low drag coefficient, one of the most important aerodynamic conditions.


computational fluid dynamics, cycling frame, drag coefficient, turbulence model, Particle Image Velocimetry


[1] Abdellah, E. & Wang, B., IOP Conference Series: Materials Science and Engineering,Volume 231, Issue 1, pp. 012173, 2017.

[2] Arpino, F., G. Cortellessa, Dell’Isola, M., Massarotti, N. & Mauro, A. High orderexplicit solutions for the transient natural convection of incompressible fluids in tallcavities. Numerical Heat Transfer; Part A: Applications, 66(8), pp. 839–862, 2014.

[3] Arpino, F., Cortellessa, G., Frattolillo, A., Caschera, M. & Pelliccio, A., Experimentaland numerical investigation of the effects of wind exposure on historical towns. EnergyProcedia, 133, pp. 312–326, 2017.

[4] Bhattacharya, S., Charonko, J.J. & Vlachos, P.P., Particle image velocimetry (PIV) uncertaintyquantification using moment of correlation (MC) plane. Measurement Scienceand Technology, 29(11), article number 115301, 2018.

[5] Capelli, C., Rosa, G., Butti, F., Ferretti, G., Veicsteinas, A. & di Prampero, P., Energycost and efficiency of riding aerodynamic bicycles. European Journal of Applied Physiology,67(1), pp. 144–149, 1993.

[6] Guilmineau, E., Computational study of flow around a simplified car body. Journal ofWind Engineering and Industrial Aerodynamics, 96(6–7), pp. 1207–1217, 2008.

[7] Keane, R.D. & Adrian, R.J., Theory of cross-correlation analysis of PIV images. AppliedScientific Research, 49(1992), pp. 191–215, 2006.

[8] Kyle, C.R. & Burke, E.R., Improving the racing bicycle. Mechanical Engineering,106(9), pp. 34–35, 1984.

[9] Launder, B.E. & Spalding, D.B., The numerical computation of turbulent flows. ComputerMethods in Applied Mechanics and Engineering, 3(2), pp. 269–289, 1974.

[10] Lukes, R.A., Hart, J.H., Chin, S.B. & Haake, S.J., The aerodynamics of mountain bicycles:The role of computational fluid dynamics. In 5th International Conference on theEngineering of Sport, Vol. 1 (Eds., Hubbard, M., Mehta, R. D. & Pallis, J. M.) U.C.Davis, U.S.A., pp. 104–110, pp. 2004.

[11] Neft, I., Scungio, M., Culver, N. & Singh, S., Simulations of aerosol filtration by vegetation:Validation of existing models with available lab data and application to nearroadwayscenario. Aerosol Science and Technology, 50(9), pp. 937–946, 2016.

[12] Scungio, M., Arpino, F., Profili, M., Rotondi, M., Focanti, V. & Bedon, G., Wind tunneltesting of scaled models of a newly developed Darrieus-style vertical axis wind turbine.European Wind Energy Association Annual Conference and Exhibition 2015, EWEA2015 - Scientific Proceedings.

[13] Tsubokura, M., Kobayashi, T., Nakashima, T., Nouzawa, T., Nakamura, T., Zhang, H.,Onishi, K. & Oshima, N., Computational visualization of unsteady flow around vehiclesusing high performance computing. Computers and Fluids, 38(5), pp. 981–990,2009.

[14] Ucho, W.H. & Sovran, G., Aerodynamics of road vehicles. Annual Review of FluidMechanics, 25(1), pp. 485–537, 1993.

[15] Zdravkovich, M.M., Aerodynamics of bicycle wheel and frame. Journal of WindEngineering & Industrial Aerodynamics, 40(1), pp. 55–70, 1992.