Aerodynamics of Badminton Shuttlecock

A study is carried out computationally to apprehend the aerodynamics of badminton shuttlecocks where the flow speed consider is 50m/sec. A comparative study between gapless and synthetic shuttlecock was carried out to establish the effect of gaps as they have a superior role in entraining the fluid and inflicting distinction between the inner and outer portion of the skirt. This difference in pressure which develops across the shuttlecock leads to drag. The effect of angle of attack on the drag and the flow has also been studied along with the validation of previous standing research.

INTRODUCTION

Aerodynamically, the shuttlecock is equivalent to a thin wall frustum attached behind a solid hemispherical dome. This shape gives an advantage of having larger speeds than projectiles used in any other sport and also a disadvantage of decelerating a lot quicker because of the drag it experience (Lin.C.S.H et.al, 2014). More information on shuttlecock can be found on https://en.wikipedia.org/wiki/Shuttlecock.The gapless model of the shuttlecock used, conjointly has the similar dimensions as that of a synthetic shuttlecock.

The synthetic and the gapless models are investigated and validated. For achieving the better understanding of the effect of gaps in the skirt, computations were carried out for a shuttlecock with no gaps. Since the angle of attack keeps changing throughout the trajectory of the flight of the shuttlecock, so angle of attack becomes an important parameter to be focused upon. The flow regime, coefficient of pressures, tangential velocity and radial velocity are studied for synthetic shuttlecock at various angle of attacks and the values of coefficient of drag are obtained for them.

GEOMETRIC MODELS OF SHUTTLECOCK

The synthetic shuttlecock and the gapless shuttlecock are made using Solidworks. The synthetic model is based on the properties of Mavis 350 from Yonex. The following are the characteristics of the synthetic model-

Walls are non-porous
There are sixteen panels in shuttlecock.
Angle subtended by each panel is 22.5◦ at the center.
The diameter, of the biggest circle is 65 mm

The length, L, of the shuttlecock is 80 mm

Fig.1a.Synthetic shuttlecock

Fig.1b.Gapless shuttlecock

Figure-1 Dimensions of the shuttlecock

MESH

The shuttlecock is enclosed in a cylindrical outer domain (diameter = 350 mm) with the upstream boundaries at x = −150mm and downstream boundaries at x = 650 mm respectively, from the nose of the shuttlecock.

Fig.2. Outer cylindrical domain

The figure below (Fig.3) shows a mesh of synthetic shuttlecock. The following mesh consists of 10.86 million unstructured and tetrahedral elements and 1.91 million nodes.

Fig.3. Mesh for synthetic shuttlecock

The figure below (Fig4) shows a mesh of gapless shuttlecock. This mesh consists of 9.78 million unstructured and tetrahedral elements and 1.71 million nodes

Fig.4.Mesh for gapless shuttlecock

A finer mesh was generated near the surface to capture the elaborate flow pattern. The whole domain is split into 3 main parts-

· A frustum shaped inner most domain

· An intermediate region and

· The coarse outer region.

Re = rho*v*D/mu (2)

Computations are carried for Re = 2.22 × 10⁵. The drag coefficient computed with synthetic shuttlecock is 0.70 and the drag coefficient with gapless shuttlecock is 0.48. These values are in approximate agreement with the previous established results (Verma.A et.al, 2013) with the error of about 7% approximately.

DRAG COEFFICIENT

Flow is investigated for Re = 2.22 x 10⁵ for both the shuttlecocks. The effect of the gaps is also investigated by comparing the results of gapless and synthetic model. The analysis gives the values of coefficient of drag 0.70 for synthetic shuttlecock and value of 0.48 for gapless shuttlecock. This is in close accordance with the standard results published earlier (Verma.A et.al, 2013). Adding to this we get to know that drag coefficient forgapless shuttlecock is less than that for the synthetic shuttlecock.

Fig.5. Graph showing variation of drag coefficient for various shuttlecock models (Verma. A. et.al, 2013)

PRESSURE COEFFICIENT

Fig.6. Coefficient of pressure for a) synthetic and b) gapless shuttlecock

Fig.7. C_p plots for a) synthetic shuttlecock b) gapless shuttlecock

VELOCITY FIELD

The synthetic shuttle has axial jet in the wake region. In case of gapless shuttlecock, the fluid inside the skirt is largely stagnant close to the walls because the skirt is impervious, (figure 9b). The flow in the core is associated with a large region of recirulation. Figure 9a correctly shows the presence of axial jet in case of synthetic shuttlecock.

The synthetic shuttle has an axial jet in the wake region whereas in gapless shuttlecock, the fluid inside the skirt and close to the walls is highly stagnant (figure 9b). The core is associated with a large region of recirulation. Figure 9a correctly shows the presence of axial jet in case of synthetic shuttlecock

Fig.9a. Velocity profile of synthetic shuttlecock

Fig.9b. Velocity profile of gapless shuttlecock

VELOCITY VECTORS AND STREAMLINES

Figure 10a, 10b and figure 11a, 11b clearly show the difference in the velocity vectors of both the shuttlecock

Fig.10 a) Velocity vectors for synthetic shuttlecock b) Velocity vectors for gapless shuttlecock

Fig.11a. Streamlines for synthetic shuttlecock

Fig.11b. Streamlines for gapless shuttlecock

ANGLE OF ATTACK

Angle of attack is one of the very crucial parameter which plays an important role in the flight of the shuttlecock.. Despite the immense popularity of the game the research about the variation of the properties with the angle of attack have not been much. The analysis shows an increase in C_d with increase in angle of attack and this is in accordance with the studies published earlier (C. Cohen et.al, 2015).

An attempt is made to provide comparisons between various flow properties at 0 degree, 1 degree, 2 degree and 3 degree angle of attack.

Table 1. Values of coefficient of drag at various angle of attacks

Plot for Cd vs Angle of attack

PRESSURE COEFFICIENT

Fig.12. Coefficient of pressure at various angles

Y VELOCITY

Fig.13. Y velocity at different angle of attacks

RADIAL VELOCITY AT Y = 4.5 CM (FROM THE NOSE)

Fig.14. Radial velocity at y = 4.5 cm for various angle of attacks

TANGENTIAL VELOCITY AT Y = 4.5 CM (FROM THE NOSE)

Fig.15. Tangential velocity at y = 4.5cm for various angle of attacks

CONCLUSIONS

A computational study for understanding the aerodynamics of a badminton shuttlecock has been carried out with synthetic and gapless models. To understand the effect of certain parameters like gaps, various computations were done for both shuttlecocks at 50m/sec speed and Reynolds number of 2.22×10⁵. It is concluded that the pressure difference between inside and outside of the skirt is the main contributor to the drag and much of the drag is from the net in synthetic shuttlecocks. This is the reason that the synthetic shuttlecock results in more drag and the gapless shuttlecock experiences lesser drag.

The tangential speed in synthetic shuttlecock is very small because the fluid at the upper end of skirt passes outside due to the presence of gaps.

Drag increases as the value of angle of attack increases this is partially proved by the values of the coefficient of drag obtained for angle 0 to 3 degree.

REFERENCES

Aerodynamics of badminton shuttlecocks. Journal of Fluids and structures Volume 41, 89-98. Aekaansh Verma, Ajinkya Desai, Sanjay Mittal, 2013
Aerodynamic properties of badminton shuttlecock. International Journal of Mechanical and Materials Engineering 4 (3), 266–272. Asai, T., Kamemoto, K., 2011.
The physics of badminton. New Journal of Physics, 2015. Caroline Cohen, Baptiste Darbois Texier, David Quere and Christophe Clanet.
Aerodynamics of badminton shuttlecock: Characterization of flow around a conical skirt with gaps, behind a hemispherical dome. Journal of wind engineering and industrial aerodynamics Volume 127, 29-39. C.S.H.Lin, C.K.Chua, J.H.Yeo, 2014

Page updated

Google Sites

Report abuse