A Practical Analysis of Unsteady Flow around a Bicycle Wheel, Fork and partial Frame using CFD

Godo, Matthew N.; Corson, David; Legensky, Steve M.; Light, Intelligent

doi:10.2514/6.2011-1237

Cited by 6 publications

(4 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Godo et al, in particular, have produced some of the most extensive CFD analyses of wheels [34,35] and the interaction between the front wheel, the fork, and the down tube [74]. Going beyond the capabilities of wind tunnel analysis, Godo et al [34,35] were able to resolve the contributions of the various components of a wheel-hub, spokes, and rim-to the overall drag of the system.…”

Section: Wheelsmentioning

confidence: 99%

Riding against the wind: a review of competition cycling aerodynamics

et al. 2017

View full text Add to dashboard Cite

Aerodynamics has such a profound impact on cycling performance at the elite level that it has infiltrated almost every aspect of the sport from riding position and styles, equipment design and selection, race tactics and training regimes, governing rules and regulations to even the design of new velodromes. This paper presents a review of the aspects of aerodynamics that are critical to understanding flows around cyclists under racing conditions, and the methods used to evaluate and improve aerodynamic performance at the elite level. The fundamental flow physics of bluff body aerodynamics and the mechanisms by which the aerodynamic forces are imparted on cyclists are described. Both experimental and numerical techniques used to investigate cycling aerodynamic performance and the constraints on implementing aerodynamic saving measures at the elite level are also discussed. The review reveals that the nature of cycling flow fields are complex and multi-faceted as a result of the highly three-dimensional and variable geometry of the human form, the unsteady racing environment flow field, and the non-linear interactions that are inherent to all cycling flows. Current findings in this field have and will continue to evolve the sport of elite cycling while also posing a multitude of potentially fruitful areas of research for further gains in cycling performance.

show abstract

Section: Wheelsmentioning

confidence: 99%

Riding against the wind: a review of competition cycling aerodynamics

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The majority of these studies have been performed on isolated wheels and they focused on comparisons of the drag of different wheels [6,[9][10][11][12][13][14][15], on the aerodynamic drag reduction by adding external elements like claddings or splitter plates [16,17], on the aerodynamic influence of the tire width to rim width ratio [18], the impact of wheel rotation on the aerodynamic drag [16,19], the influence of the rotational moment on the total power required to move the wheel [11] and the influence of computational parameters and the type of wheel/ground contact modeling to the aerodynamics of spoked wheels [20][21][22]. Only a few studies have focused on the aerodynamics of non-isolated cycling wheels, including those by Godo et al [23], Barry et al [24] and Petrone et al [25]. In addition, Kyle [26] mentioned that rear wheels had about 40% lower drag than front wheels, as rear wheels are situated partly in the wake of the rest of the bicycle.…”

Section: Introductionmentioning

confidence: 99%

“…Godo et al [23] found that the computed wheel drag was only slightly influenced by the presence of a fork and the remaining bicycle components. Only the front part of a cut racing bicycle frame was included in the CFD simulations and that two deep-rim spoked wheels and a tri-spoke wheel were considered.…”

Section: Introductionmentioning

confidence: 99%

Impact of wheel rotation on the aerodynamic drag of a time trial cyclist

2021

View full text Add to dashboard Cite

Aerodynamic drag is the main resistive force in cycling at high speeds and on flat terrain. In wind tunnel tests or computational fluid dynamics simulations, the aerodynamic drag of cycling wheels is often investigated isolated from the rest of the bicycle, and sometimes in static rather than rotating conditions. It is not yet clear how these testing and simulating conditions influence the wheel aerodynamic performance and how the inclusion of wheel rotation influences the overall measured or computed cyclist drag. This study presents computational fluid dynamics simulations, validated with wind tunnel tests, that indicate that an isolated static spoked front wheel has a 2.2% larger drag area than the same wheel when rotating, and that a non-isolated static spoked front wheel has a 7.1% larger drag area than its rotating counterpart. However, rotating wheels are also subjected to the rotational moment, which increases the total power required to rotate and translate the wheel compared to static conditions where only translation is considered. The interaction with the bicycle frame and forks lowers the drag area of the front wheel by 8.8% for static and by 12.9% for the rotating condition, compared to the drag area of the isolated wheels. A different flow behavior is also found for static versus rotating wheels: large low-pressure regions develop from the hub for rotating wheels, together with a lower streamwise velocity region inside the circumference of the wheel compared to static wheels. The results are intended to help in the selection of testing/simulating methodologies for cycling spoked wheels.

show abstract

“…Highly resolved computational fluid dynamics (CFD) has gained popularity as a tool for aerodynamic assessment in sport over the past decade or so, with considerable effort focused on cycling [1][2][3]. CFD affords practitioners insights into the detailed flow features involved in producing observed bulk effects, such as drag.…”

Section: Introductionmentioning

confidence: 99%

Improving Numerical Estimation of Cyclist Drag Area in Static Conditions Using Unsteady RANS

Javadi

Buckrell

Peterson

2020

The 13th Conference of the International Sports Engineering Association

View full text Add to dashboard Cite

Herein, we compare the drag area estimated using unsteady Reynolds-averaged Navier-Stokes (URANS), using the γ−ReΘ transitional shear stress transport (SST) k−ω (SSTLM) turbulence model with published experimental measurements of a static full-scale cyclist mannequin in an open test section wind tunnel, with the left leg fully extended. The turbulence model employs a local empirical correlation based upon a classical Blasius boundary layer behavior to predict flow transition. For a given mesh density, we aim to improve drag area estimation by modifying the empirical correlation coefficient to better capture actual boundary layer transition location around the arms and legs, to facilitate computationally economical cyclist simulations. Large Eddy Simulation (LES), in conjunction with experimental wake data in the vicinity of the arms and legs, is used to assess boundary layer shape factors, which are related to the empirical coefficient. Overall, the drag area predicted by LES is within 3.7% of the measured results, while the original SSTLM is within 7.8%. By tuning the correlation coefficient, the drag area error is improved to 6.0% at no additional computational cost. The tuning was relatively coarse, and was only considered for the appendages. In other regions, the original SSTLM coefficient seems to perform better, suggesting that local coefficient selection may lead to further improvements in results over the currently employed global value.

show abstract

A Practical Analysis of Unsteady Flow around a Bicycle Wheel, Fork and partial Frame using CFD

Cited by 6 publications

References 11 publications

Riding against the wind: a review of competition cycling aerodynamics

Riding against the wind: a review of competition cycling aerodynamics

Impact of wheel rotation on the aerodynamic drag of a time trial cyclist

Improving Numerical Estimation of Cyclist Drag Area in Static Conditions Using Unsteady RANS

Contact Info

Product

Resources

About