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Aerodynamic forces act on a golf ball during flight. For that purpose in order to develop a golf ball with high performance, it is important to analyze aerodynamic characteristics of the golf ball. On the other hand, dimple pattern of a golf ball is complicate and the influence of dimples hasn’t been investigated in detail. Therefore the influence...
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Golf ball ideal plan has been considered for over a century. Generally, golf balls move at long-distance and high speed. Dimples golf ball have a fundamental impact by streamlined flow properties and also the flight heading. Streamlined highlights the golf ball where it was still incomplete in the appearance of an essential interior information. In...
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... As summarised elsewhere (Evans & Tuttle, 2015), the artificial environment and surrogate performance measures used in laboratory-based research studies on golf might not accurately reflect on-course performance. The use of a net, for instance, limits the ability of golfers to focus on a driving target, and covering the golf ball in reflective tape would have altered its aerodynamic properties (Naruo & Mizota, 2014). Although improving clubhead speed might have a resultant positive effect on carry distance using the SuperSpeed warm-up, this needs further empirical evidence given that ball speed was not enhanced and driver accuracy not examined herein. ...
High-level golfers use various warm-up strategies to enhance clubhead and ball speed, including weighted equipment. We investigated the acute effects of the SuperSpeed Golf™ weighted-club warm-up on clubhead, ball, and swing kinematics, and the persistence of any acute effects in subsequent sets. Twelve competitive golfers (handicap < 3.0) completed five sets of five swings using their own drivers under two randomised warm-up conditions (Control and SuperSpeed). We compared swing, peak segment and club angular velocity, and centre of mass (COM) parameters collected using a 3D motion capture system (500 Hz) between conditions. The temporal persistence of any meaningful (Cohen’s d ≥ small) and significant (p≤ 0.05) effect detected in the first set was investigated in subsequent sets. SuperSpeed led to small significant changes in clubhead speed (2.6 mph); downswing time; peak angular velocities of the torso, lead arm, and club; and two COM variables in the initial set. There was no significant change in ball speed, resulting in a large negative change in smash factor acutely (d − 0.82, p= 0.009). Nearly all changes observed were no longer meaningful or significant in subsequent sets. Overall, golfers can expect an increase in driving clubhead speed on the first tee using the SuperSpeed Golf™ vs Control warm-up, with trivial effects from the second tee onwards.
... This is considered to be due to the fact that the depth (2 mm) and width (5 mm) of the groove introduced in this study are shallower and narrower than the depth (3.8 mm) and width (10 mm) of the seam. In addition, previous research on golf balls has shown that the form of the dimples on the surface of the ball has a large impact on the ball's aerodynamics, and that the ball's wind velocity range characteristics depend on the size of the dimples [18]. We speculate that the deep seams and shallow grooves on the surface of the soccer ball in this study act like dimples of different sizes on a golf ball. ...
Soccer balls have undergone dramatic changes in their surface structure that can affect their aerodynamics. The properties of the soccer ball surface such as the panel shape, panel orientation, seam characteristics, and surface roughness have a significant impact on its aerodynamics and flight trajectory. In this study, we performed wind-tunnel tests to investigate how the introduction of grooves on the surface of a soccer ball affects the flight stability and aerodynamic forces on the ball. Our results show that for soccer balls without grooves, changing the panel orientation of the ball causes a significant change in the drag coefficient. Soccer balls with grooves exhibited a smaller change in air resistance (Cd) in the supercritical region (20 to 30 m/s; 3.0 × 10 5 ≤ Re ≤ 4.7 × 10 5), compared to the ungrooved ball where only the panel orientation was changed. Furthermore, at power-shot speeds (25 m/s), the grooved ball exhibited smaller variations in lift force and side force than the ungrooved ball. These results suggest that a long groove structure on the surface of the soccer ball has a significant impact on the air flow around the ball in the supercritical region, and has the effect of keeping the air flow separation line constant.
... Takeshi Naruo [14] investigated the effect of dimples depth on lift coefficient of the golf ball with varying launch speeds. For investigation purposes, wind tunnel technique was developed by installing rotating device inside the golf ball. ...
Golf ball aerodynamics is significantly multifaceted as compared to other sports balls due to the presence of small dimples, which serve as a source of surface roughness and drag reduction. Overall aerodynamic performance of a golf ball is influenced by flow behavior over these dimples. Consequently, flow phenomena over the dimples is effected by various dimple characteristics, of which dimples geometry, size, shape, depth, and pattern are considered significant. Dimple characteristics continue to be an active area of research because the results thereof, affect the assertions, sales, and the performance of different commercially available golf balls. Dimples on the other hand also enhance the intricacy of flow over a golf ball; and due to this fact aerodynamics of a golf ball is yet to be fully recognized despite of considerable amount of available literature. Previous studies focused on overall aerodynamic performance of the golf ball through experimental analysis and Computational Fluid Dynamics (CFD) simulations; however, available literature still lacks detailed analysis of pertinent dimple characteristics. In this paper, dimple depth effect on the drag performance of a golf ball has been examined by employing numerical simulations, followed by validation through bench mark wind tunnel results of F. Alam (Procedia-2011). CFD simulations in ANSYS Fluent ® have been carried out for 5 balls with varied dimple depth over various velocities (wind). It has been established that golf ball drag coefficient varies considerably as the dimple geometry is varied. The results specify a direct relationship between dimple depth ratio and transitioning Reynolds number. As the depth ratio is increased the transitioning Reynolds number is lowered and this also serves to increase the drag coefficient in transcritical regime. A positive linear relationship was also established between coefficient of drag and relative roughness.
... A hook is a ball flight in which the ball curves from right to left due to a small amount of side-spin being imparted to it at impact. Similarly, a slice is a ball flight in which the ball curves from left to right, due to side-spin imparted to the ball at impact in the opposite direction from the one used to obtain the hook result [5][6][7][8][9][10][11]. Each of these terms is defined for a player using "right-handed" clubs, and changes meaning if the player uses "lefthanded" clubs. ...
... Shallow dimples generally give the ball a lower trajectory and good control in the wind; whereas large dimples give the ball a higher trajectory and longer flight time [1][2][3][4]. Naruo and Mizota [5] worked on the influence of golf ball dimples on aerodynamic behaviour of the airflow around the ball using a wind tunnel and rotating device. By using golf balls whose dimples have different depths, they found that shallower dimples resulted to the larger lift coefficient. ...
... The golf ball dimple size, depth and number significantly influence the flight trajectory and consequently determine how far the ball travels when played. Several experimental studies such as Naruo and Mizota [5], Baek and Kim [7], Alam et al. [8] and Aoki et al. [1][2][3][4] have shown that shallow dimples generate more spin of a golf ball than deep dimples. Additionally, these studies also revealed that smallsized dimples generally result to a lower trajectory whereas large-sized dimples result to a higher trajectory and longer flight time. ...
... The aerodynamics of various sports balls has been an area of long-standing interest for both the general public [1-5] and the professional sports scientist [6][7][8]. Golf balls [9,10], cricket balls [11,12], baseballs [13,14] and spheres more generally [15,16] have all been areas of research interest. Of all the sports balls, there is more worldwide interest in the aerodynamics of football (soccer) balls than any other. ...
Drag and lift coefficients of recent FIFA world cup balls are examined. We fit a novel functional form to drag coefficient curves and in the absence of empirical data provide estimates of lift coefficient behaviour via a consideration of the physics of the boundary layer. Differences in both these coefficients for recent balls, which result from surface texture modification, can significantly alter trajectories. Numerical simulations are used to quantify the effect these changes have on the flight paths of various balls. Altitude and temperature variations at recent world cup events are also discussed. We conclude by quantifying the influence these variations have on the three most recent world cup balls, the Brazuca, the Jabulani and the Teamgeist. While our paper presents findings of interest to the professional sports scientist, it remains accessible to students at the undergraduate level.
... It is a well known fact that the dimples on a golf-ball reduces its drag [1] by keeping the flow attached to the ball for a longer period of time and thus delaying flow separation. But it has never been implemented on a vehicle to test how the possible reduction in drag could be converted to an increase in fuel efficiency of the vehicle. ...
... It was tailor-made so that it can not only accommodate the different test models, but can also be easily fitted on to the available wind tunnel. It had a digital display which displayed the drag force readings in grams, which were later converted to coefficient of drag values using equation (1). ...
With rising fuel prices and decreasing fuel reserves, vehicles are being made more fuel efficient. Vehicle aerodynamics plays a crucial role in determining fuel consumption. This paper investigates the influence of passive flow control technique of imparting a dimpled body design in aerodynamic drag reduction by delaying flow separation and reducing the amount of wake region created behind the vehicle. For this, Ahmed bodies with 25° and 35° of slant angles have been used. Experiments were performed to compare the drag variations at various velocities when dimples of a fixed aspect ratio were imparted to the top surface of the Ahmed body behind the rear legs. For the 25° Ahmed body, the highest drag reduction of about 40% was obtained for the lowest flow velocity of 3m/s. Previous literature shows a sudden increase in drag force when the slant angle is increased beyond 30° .Hence tests were conducted on the Ahmed body with 35° slant angle with and without dimples. It revealed that the dimples had no effect in reducing its drag at low flow speeds. In fact, it was found that the dimpled body suffered an increased drag at higher velocities. Based on the studies conducted and by also taking the ease of fabrication into consideration, dimples were imparted on the super-mileage vehicle developed by us for ‘Shell Eco Marathon Asia 2015’. The dimpled design imparted an increase in fuel efficiency of about 7%. This paper thus serves to prove the aerodynamic as well as fuel efficiency advantage that the dimpled design imparts to a vehicle.
The surface of a golf ball is provided with innumerable dents called dimples to improve the flight distance. In this study, we manufactured 15 model balls in which the dimple occupancy and the dimple volume ratio was changed by the dimple diameter and the number of dimples, and the dimple shapes. Using these balls, we carried out lift and drag measurements of the rotating balls in wind tunnel experiments. Then, a flight trajectory simulation was performed based on the obtained experimental results. As a result, the influence of the base shape showed different results for both drag and lift coefficients for each occupancy. However, the drag coefficient decreased and the lift coefficient increased as the dimple volume ratio increased regardless of the dimple shape. In addition, the relationship between the lift-drag ratio and the dimple volume ratio showed that the lift-drag ratio decreased as the dimple volume ratio increased. The flight trajectory simulation results showed that the flying distance was greater for O=52.6% and O=63.1% with a conical base when the dimple volume ratio was small and the dimple depth is DD/d=4.55×10⁻³. Two spheres with a spherical base and a conical base at O=83.1%, also exhibited similar flying distances. However, the flight distance tends to increase as the dimple volume ratio decreases. The ball's trajectory was lower when the volume ratio was small, and higher trajectory was obtained when the occupancy ratio was high.
For golfers, the length of the flight distance is very important for improving scores. Therefore, the surface of a golf ball is provided with innumerable dents called dimples to improve the flight distance. These dimples can be characterized by the dimple occupancy and dimple volume ratio. Therefore, we manufactured model balls in which the dimple occupancy was changed by the dimple diameter and the number of dimples, and the dimple depth was changed to change the dimple volume ratio. Fifteen model balls were designed using 3D CAD and then 3D printed. Using these balls, we carried out lift and drag measurements in wind tunnel experiments. Then, a flight trajectory simulation was performed based on the obtained experimental results, and the effects of the dimple occupancy and dimple volume ratio on the flight distance were elucidated. In rotating golf balls, when the dimple depth was shallow, i.e., D/d = 4.55 × 10–3, and the occupancy ratio was 80% or higher, the lift-drag ratio was higher, and the flying distance was increased. However, when the dimple depths were D/d = 6.82 × 10–3 and D/d = 9.09 × 10–3, there was almost no effect of the occupancy ratio. Furthermore, when comparing these two depths, the lift-drag ratio was bout 15% lower for deeper dimples. With respect to the dimple volume ratio, the drag coefficient increased with increasing dimple volume ratio. The lift-drag ratio was also highest in the dimple volume ratio range of 11.0–12.0 × 10–3.
