# Available online at Procedia Engineering 200 (2010) (2009) In situ drag measurements of sports balls

Save this PDF as:

Size: px
Start display at page:

Download "Available online at Procedia Engineering 200 (2010) (2009) In situ drag measurements of sports balls"

## Transcription

1 Available online at Procedia Engineering 200 (2010) (2009) Procedia Engineering 8 th Conference of the International Sports Engineering Association (ISEA) In situ drag measurements of sports balls Jeffrey R. Kensrud a, Lloyd V. Smith a * a School of Mechanical and Materials Engineering, Washington State University, 201 Sloan, Spokane St., Pullman, WA 99164, USA Received 31 January 2010; revised 7 March 2010; accepted 21 March 2010 Abstract Aerodynamic drag on sports balls is typically measured in wind tunnels. There is a concern that fixtures needed to support the ball in a wind tunnel may influence its drag. Measurements under game conditions have been attempted, but are difficult to interpret from the data scatter and are not controlled. The following considers drag measurements from a ball propelled through static air in a laboratory setting. High speed light gates were used to measure drag, including the effects of ball rotation. Drag was observed to depend on the ball speed, rotation, roughness, and orientation. A so-called drag crisis was observed for a smooth sphere and was comparable to wind tunnel data. Rough sports balls, such as a baseball, showed evidence of a small drag crisis that was less apparent than the smooth sphere. c Published by by Elsevier Ltd. Ltd. Keywords: drag; sport ball aerodynamics; drag crisis, drag measurements. 1. Introduction Understanding the flight of a ball involves two aerodynamic properties, lift and drag. Lift can be described as the force, not including gravity, on a ball that is directed perpendicular to the ball s trajectory. Drag is the force, F d, in the direction opposing the ball s flight path [1]. The drag coefficient, C d, is found from [2] (1) where ρ is the density of air, A is the cross sectional area of the ball, and V is the speed of the ball. Drag is a function of surface roughness, velocity, and orientation of the ball. It is convenient to use a non-dimensional form of velocity, expressed in terms of the Reynolds number, R e, defined by (2) * Corresponding author. address: c 2010 Published by Elsevier Ltd. doi: /j.proeng

2 2438 J.R. Kensrud, L.V. Smith / Procedia Engineering 2 (2010) J.R. Kensrud & L.V. Smith / Procedia Engineering 00 (2010) Figure 1 - Flow over a smooth cylinder: (a) R e < 3x10 5, flow stays laminar in the boundary layer until 80 where it separates; (b) 3x10 5 < R e < 3x10 6, flow separates at 80 becomes turbulent and reconnects before separating again at 120 degrees; (c) 3x10 6 < R e, flow is turbulent in the boundary layer on the front and stays turbulent until separating at 120. The stagnation point is identified by X in each figure. where D is diameter of the ball and υ is kinematic viscosity of air. The effect of speed on drag can be described by three characteristic ranges, as illustrated in Figure 1. At low Reynolds number, (a), flow is laminar until separation occurs at roughly 80 from the stagnation point [3]. When the Reynolds number is increased, region (b), the separation region becomes turbulent and attaches itself again, carrying the separation point to the backside of the ball to about 120 from the stagnation point. As the separation point moves to the back of the ball, drag is reduced. The reduction in drag can be large and occur over a small change in the Reynolds number. Region (b) is referred to as the Drag Crisis, and often occurs at game speeds. As the Reynolds number is increased further, region (c), the flow becomes completely turbulent in the boundary layer just after the stagnation point, causing the drag to increase again. The drag crisis has been observed on a smooth sphere for many years. Millikan and Klein [4] explored the drag crisis in their free flight test finding C d on a smooth sphere as low as Achenbach [5] analyzed how surface roughness on a sphere can change behaviour in the critical Reynolds region. His data suggested that as surface roughness increased on a sphere the drag crisis was induced at a lower Reynolds number and was less severe. Frohlich [6] also analyzed how surface roughness can change the behaviour of the drag crisis. Frohlich went on to explain if a baseball acted like a rough sphere, the drag crisis could help explain the behaviour of pitched or batted baseballs. Alaways, Mish, and Hubbard [7] analyzed baseball pitches by triangulating ball location from video taken during the 1996 Summer Olympic Games. Their data showed evidence of a drag crisis with a drag coefficient as low as An improved video tracking system involving Major League Baseball (PITCHf/x) [8] showed little evidence of a drag crisis, however. The effect of ball rotation has primarily been directed towards lift. To the authors knowledge, the only study involving rotational drag on a sports-like ball is that of Bearman and Harvey who rotated dimpled spheres resembling a golf ball in a wind tunnel [9]. They found drag increased with rotation. Mehta attributed the drag increase with lift effects [10]. The following considers the effect that surface roughness, velocity, orientation and rotation have on the drag force. The study was conducted in a laboratory setting to improve the accuracy of drag measurements over that achievable in game conditions. Balls were projected through static air to avoid interaction with ball support devices used in wind tunnel experiments. 2. Methods and experimental setup The change in ball speed was found using two light boxes that measured both the position and speed of the ball. The study examined six different sports balls. The translational velocity ranged from 17.9 m/s to 60.8 m/s. A pneumatic sabot style air cannon was used to project baseballs with no rotation to study the effect of seam orientation. A high speed video camera (1000 fps, 10-4 s shutter speed) was used to record each shot to verify correct orientation and flight path. A three wheeled pitching machine (HomePlate, Sports Tutor) was used to project balls with controlled angular velocity. The three wheels were oriented 120 apart with the lower wheel aligned in the vertical direction. Tracking software was used to determine the angular velocity of each pitch.

3 J.R. Kensrud, L.V. Smith / Procedia Engineering 2 (2010) J.R. Kensrud & L.V. Smith / Procedia Engineering 00 (2010) Figure 2. Diagram showing arrangement of pitching device and light boxes used to measure ball speed and location. Once the ball was released from the pitching device, it began its path through the light boxes. Each box had an opening of meters by meters to allow enough room for a ball to enter and exit without contacting the inner walls. Each light box consisted of three pairs of light gates (Ibeam, ADC) as shown in Figure 2. Each light gate was rigidly mounted and levelled inside the light box. Velocity was found from the two vertical gates placed meters apart. Lift was found from the change in the ball s vertical position, which was measured from the light gates mounted at 45. The light boxes were placed between 4 and 5 meters apart. Balls travelling at lower speeds used the closer light box spacing, while high ball speeds used the larger light box spacing. The change in velocity between the boxes ranged from m/s. The light boxes were squared to each other and the pitching machine using a laser level. The drag force, F d, was found from [11] where V 1 and V 2 are the speeds from the first and second light boxes, respectively, m is the ball mass, and d is the distance between the light boxes. 3. Samples The sabot style air cannon allowed ball orientation to be controlled. Two different orientations of the baseball and cricket ball were used. As shown in Figure 3, a normal orientation positioned stitches perpendicular to the airflow and a parallel orientation positioned stitches parallel to the air flow. The study comprised baseballs, softballs (89 and 97 mm diameter) cricket balls, golf balls and smooth spheres. (3) a a b b Figure 3. Diagram showing the normal (a) and parallel (b) orientations. Black arrows indicate the airflow direction, white arrows indicate the ball rotation axis.

4 2440 J.R. Kensrud, L.V. Smith / Procedia Engineering 2 (2010) J.R. Kensrud & L.V. Smith / Procedia Engineering 00 (2010) Results Figure 4. Coefficient of drag for all test balls. The drag coefficient (without ball rotation) is shown for all the sports balls from this study as a function of Reynolds number in Figure 4. The drag crisis is most apparent for the golf ball and smooth sphere. The drag crisis of the smooth sphere is comparable with previous work [5], but had less magnitude and occurred at a lower Reynolds number (2x10 5 vs 3x10 5 ) [5]. As expected, the dimpled surface of the golf ball caused a drag crisis at a lower Reynolds number than the smooth sphere. The optimized dimple pattern of the golf ball appears to help maintain the relatively large magnitude of its drag crisis. While the stitched balls (baseballs, softballs, and cricket balls) show C d decreasing with increasing speed (Figs. 5, 6, and 7), the magnitude of their drag crisis was significantly smaller than the smooth sphere and golf ball. The study included balls with flat and raised stitches. Scatter in drag was larger for the balls with raised seams (NCAA baseball and 89 mm softball). The arrangement of the stitches likely plays a role in the drag crisis. As shown in Figure 1, the drag crisis is a result of turbulence developing in the boundary layer of the ball. The stitches trip the boundary layer earlier than a smooth sphere inducing turbulence and moving the flow separation point to the backside of the ball. In the normal orientation, the stitches are close to the flow separation point, which is apparently fixed to the stitch location for balls with raised seams. For smooth spheres, the separation point (and drag) depends on the air speed. For balls with raised seems, the separation point (and drag) depends on variation in ball orientation and air speed. It is not surprising, therefore, that the parallel orientation of the cricket ball exhibited the largest drag crisis; as the stitches are removed from the separation point in this orientation, providing a relatively smooth flow surface.

5 J.R. Kensrud, L.V. Smith / Procedia Engineering 2 (2010) J.R. Kensrud & L.V. Smith / Procedia Engineering 00 (2010) Figure 5. The drag coefficient of NCAA baseballs in the normal and parallel orientations. Figure 6. The drag coefficient of cricket balls in the normal and parallel orientations. Balls with raised seams (NCAA baseball and 89 mm softball) exhibited a higher relative C d and a drag crisis at a lower relative Reynolds number. Both trends are consistent for balls of higher relative roughness. The effect of spin on C d for baseballs and dimpled pitching machine balls are shown in Figure 8. The translational velocity for the rotating balls ranged from 27 to 44 m/s with angular velocities from 22 to 4731 rpm. The balls were rotated in a normal or 4-seam orientation as defined in Figure 3. The rotational and linear velocities were normalized according to [12] where S is the spin factor, ω is the angular velocity, and r is the ball radius. Similar to rotating dimpled spheres observed elsewhere [9], drag on a baseball was observed to increase with spin but with less magnitude. While the effect is small, it is measurable and affects the ball flight. The NCAA ball had an average C d of 0.34 and 0.41 for non-rotating and rotating conditions, respectively. To illustrate the effect of rotation on drag, the dimpled pitching machine ball without rotation is included in Figure 8 over the same translational velocity range as the rotating balls. (4) Figure 7 Drag coefficient of MLB baseballs in the parallel orientation.?/v) Figure 8. Drag coefficient of baseballs rotating in the normal and parallel oreintations compared to a dimpled baseball.

6 2442 J.R. Kensrud, L.V. Smith / Procedia Engineering 2 (2010) J.R. Kensrud & L.V. Smith / Procedia Engineering 00 (2010) Pitched balls (including knuckleballs) usually have some rotation and therefore do not achieve the low C d observed in Figure 7. Thus, in play one should expect pitched balls to have a drag coefficient between 0.3 and 0.4. However for pitchers like Tim Wakefield, who can deliver a ball with no rotation, a pronounced drag crisis is more likely to occur, where the C d could be as low as Concluding remarks The preceding has considered the drag of sports balls obtained by projecting the balls through still air. A sabot style air cannon provided ball controlled orientation without rotation, revealing the sensitivity of drag to the stitch orientation. The drag of non-rotating balls was comparable to previous experiments. Smooth spheres, golf balls, and balls with flat seams showed a strong drag crisis, while raised seam balls showed only a weak drag crisis. Rotation had a measurable effect on drag, increasing the average C d on a baseball by 20%. It is difficult to pitch baseballs with no rotation. Hence, most baseball pitches will have a C d of 0.35 (the average drag observed for rotating balls). References [1] R. K. Adair, The Physics of Baseball. 3 rd ed. (HarperCollins Publishers, New York, 2002), pp [2] C.T. Crowe, F. D. Elger, J. A. Roberson. Engineering Fluid Mechanics. 8th ed. (John Wiley & Sons, Hoboken, 2005) pp 440. [3] R. L. Panton. Incompressible Flow. 3rd ed. (John Wiley, Hoboken, 2005) pp [4] C.B. Millikan, A.L. Klein. The effect of turbulence. An investigation of maximum lift coefficient and turbulence in wind tunnels and in flight, Aircraft Engineering, Vol 5, , [5] E. Achenbach. The effects of surface roughness and tunnel blockage on flow past spheres, Journal of Fluid Mechanics, Vol. 65, (1974). [6] C. Frohlich. Aerodynamic drag crisis and its possible effect on the flight of baseballs, American Journal of Physics, 52, (1984). [7] L. W. Alaways, S. P. Mish, M. Hubbard. Identification of Release Conditions and Aerodynamic Forces in Pitched-Baseball Trajectories, Journal of Applied Biomechanics, Vol. 17, (2001). [8] A. M. Nathan. Analysis of PITCHf/x Pitched Baseball Trajectories, University of Illinois, 8 July, 2009 < [9] P. W. Bearman, and J. K. Harvey. Golf ball aerodynamics, Aeronautical Quarterly, Vol. 27, (1976). [10] R. Mehta. Aerodynamics of Sports Balls, Ann. Rev. Fluid Mechanics, , (1985). [11] R. D. Knight. Physics for Scientists and Engineers. Vol. 1 (Pearson Education, Boston, 2007). [12] A. M. Nathan. The effect of spin on the flight of a baseball., American Journal of Physics, 76 (2), (2008).

### ScienceDirect. Relating baseball seam height to carry distance

Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 112 (2015 ) 406 411 7th Asia-Pacific Congress on Sports Technology, APCST 2015 Relating baseball seam height to carry distance

### Effects of seam and surface texture on tennis balls aerodynamics

Available online at www.sciencedirect.com Procedia Engineering 34 (2012 ) 140 145 9 th Conference of the International Sports Engineering Association (ISEA) Effects of seam and surface texture on tennis

### Forces that govern a baseball s flight path

Forces that govern a baseball s flight path Andrew W. Nowicki Physics Department, The College of Wooster, Wooster, Ohio 44691 April 21, 1999 The three major forces that affect the baseball while in flight

### Effects of turbulence on the drag force on a golf ball

European Journal of Physics PAPER Effects of turbulence on the drag force on a golf ball To cite this article: Rod Cross 2016 Eur. J. Phys. 37 054001 View the article online for updates and enhancements.

### Available online at ScienceDirect. Procedia Engineering 105 (2015 )

Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 105 (2015 ) 317 322 6th BSME International Conference on Thermal Engineering (ICTE 2014) Aerodynamic study of FIFA-approved

### A study of golf ball aerodynamic drag

Available online at www.sciencedirect.com Procedia Engineering 13 (2011) 226 231 5 th Asia-Pacific Congress on Sports Technology (APCST) A study of golf ball aerodynamic drag Firoz Alam *, Tom Steiner,

### The validity of a rigid body model of a cricket ball-bat impact

Available online at www.sciencedirect.com Procedia Engineering 34 (2012 ) 682 687 9 th Conference of the International Sports Engineering Association (ISEA) The validity of a rigid body model of a cricket

### Characteristics of modern soccer balls

Available online at www.sciencedirect.com Procedia Engineering 34 (01 ) 1 17 9 th Conference of the International Sports Engineering Association (ISEA) Characteristics of modern soccer balls Takeshi Asai

### Available online at ScienceDirect. The 2014 Conference of the International Sports Engineering Association

Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 72 ( 2014 ) 435 440 The 2014 Conference of the International Sports Engineering Association Accuracy performance parameters

### Modeling Pitch Trajectories in Fastpitch Softball

Noname manuscript No. (will be inserted by the editor) Modeling Pitch Trajectories in Fastpitch Softball Jean M. Clark Meredith L. Greer Mark D. Semon Received: date / Accepted: date Abstract The fourth-order

### THE CURVE OF THE CRICKET BALL SWING AND REVERSE SWING

Parabola Volume 32, Issue 2 (1996) THE CURVE OF THE CRICKET BALL SWING AND REVERSE SWING Frank Reid 1 It is a well known fact in cricket that the new ball when bowled by a fast bowler will often swing

### The effect of baseball seam height on the Magnus Force

The effect of baseball seam height on the Magnus Force Shawn Bowman Physics Department, The College of Wooster, Wooster, Ohio 44691, USA (Dated: May 7, 2014) Many people do not know that Major League and

### ScienceDirect. Rebounding strategies in basketball

Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 72 ( 2014 ) 823 828 The 2014 conference of the International Sports Engineering Association Rebounding strategies in basketball

Parasite Drag by David F. Rogers http://www.nar-associates.com Copyright c 2005 David F. Rogers. All rights reserved. How many of you still have a Grimes rotating beacon on both the top and bottom of the

### THEORY OF WINGS AND WIND TUNNEL TESTING OF A NACA 2415 AIRFOIL. By Mehrdad Ghods

THEORY OF WINGS AND WIND TUNNEL TESTING OF A NACA 2415 AIRFOIL By Mehrdad Ghods Technical Communication for Engineers The University of British Columbia July 23, 2001 ABSTRACT Theory of Wings and Wind

### Engineering Flettner Rotors to Increase Propulsion

Engineering Flettner Rotors to Increase Propulsion Author: Chance D. Messer Mentor: Jeffery R. Wehr Date: April 11, 2016 Advanced STEM Research Laboratory, Odessa High School, 107 E 4 th Avenue, Odessa

### A Comparison of Jabulani and Brazuca Non-Spin Aerodynamics

A Comparison of Jabulani and Brazuca Non-Spin Aerodynamics Proc JMechE Part P: J Sports Engineering and Technology ():1 13 The Author(s) 2 Reprints and permission: sagepub.co.uk/journalspermissions.nav

### Sport fluid dynamics, Aerodynamics part

20 th July, ISBS2016 Applied Sessions Sport fluid dynamics, Aerodynamics part Aerodynamics of sports balls It is known the ball trajectory in flight is affected by the aerodynamic characteristics (Cd &

### What New Technologies Are Teaching Us About the Game of Baseball

What New Technologies Are Teaching Us About the Game of Baseball Alan M. Nathan University of Illinois at Urbana-Champaign a-nathan@illinois.edu October 15, 2012 Abstract The trajectory of a baseball moving

### Agood tennis player knows instinctively how hard to hit a ball and at what angle to get the ball over the. Ball Trajectories

42 Ball Trajectories Factors Influencing the Flight of the Ball Nathalie Tauziat, France By Rod Cross Introduction Agood tennis player knows instinctively how hard to hit a ball and at what angle to get

### CFD SIMULATION STUDY OF AIR FLOW AROUND THE AIRFOIL USING THE MAGNUS EFFECT

Magnus effect, simulation, air flow Patryk SOKOŁOWSKI *, Jacek CZARNIGOWSKI **, Paweł MAGRYTA *** CFD SIMULATION STUDY OF AIR FLOW AROUND THE AIRFOIL USING THE MAGNUS EFFECT Abstract The article presents

### ScienceDirect. Aerodynamic body position of the brakeman of a 2-man bobsleigh

Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 112 (2015 ) 424 429 7th Asia-Pacific Congress on Sports Technology, APCST 2015 Aerodynamic body position of the brakeman of

Available online at www.sciencedirect.com Procedia Engineering 3 () 94 99 5 th Asia-Pacific Congress on Sports Technology (APCST) Basketball free-throw rebound motions Hiroki Okubo a*, Mont Hubbard b a

### Bending a soccer ball with math

Bending a soccer ball with math Tim Chartier, Davidson College Aerodynamics in sports has been studied ever since Newton commented on the deviation of a tennis ball in his paper New theory of light and

### Why does a golf ball have dimples?

Página 1 de 5 Why does a golf ball have dimples? page 1 A golf ball can be driven great distances down the fairway. How is this possible? Is the drive only dependent on the strength of the golfer or are

### Aerodynamic characteristics around the stalling angle of the discus using a PIV

10TH INTERNATIONAL SYMPOSIUM ON PARTICLE IMAGE VELOCIMETRY PIV13 Delft, The Netherlands, July 1-3, 2013 Aerodynamic characteristics around the stalling angle of the discus using a PIV Kazuya Seo 1 1 Department

### Available online at ScienceDirect. Brendan Kays a, Lloyd Smith a *

Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 72 ( 2014 ) 563 568 The 2014 conference of the International Sports Engineering Association Field Measurements of Ice Hockey

### T he uniqueness of the shape and design of a ball to a particular sport has meant that there were very little

OPEN SUBJECT AREAS: MECHANICAL ENGINEERING FLUID DYNAMICS Received 19 February 2014 Accepted 15 April 2014 Published 29 May 2014 Correspondence and requests for materials should be addressed to S.H. (sr7931@hotmail.

### Aerodynamic drag of modern soccer balls

Asai and Seo SpringerPlus 2013, 2:171 a SpringerOpen Journal RESEARCH Open Access Aerodynamic drag of modern soccer balls Takeshi Asai 1* and Kazuya Seo 2 Abstract Soccer balls such as the Adidas Roteiro

### EXPERIMENTAL INVESTIGATION OF LIFT & DRAG PERFORMANCE OF NACA0012 WIND TURBINE AEROFOIL

EXPERIMENTAL INVESTIGATION OF LIFT & DRAG PERFORMANCE OF NACA0012 WIND TURBINE AEROFOIL Mr. Sandesh K. Rasal 1, Mr. Rohan R. Katwate 2 1 PG Student, 2 Assistant Professor, DYPSOEA Ambi Talegaon, Heat Power

### Available online at Procedia Engineering 200 (2010) (2009)

Available online at www.sciencedirect.com Procedia Engineering 200 (2010) (2009) 000 000 2413 2418 Procedia Engineering www.elsevier.com/locate/procedia 8 th Conference of the International Sports Engineering

### The Effect of Driver Mass and Shaft Length on Initial Golf Ball Launch Conditions: A Designed Experimental Study

Available online at www.sciencedirect.com Procedia Engineering 34 (2012 ) 379 384 9 th Conference of the International Sports Engineering Association (ISEA) The Effect of Driver Mass and Shaft Length on

### AERODYNAMICS SPORTS BALLS

Ann. Rev. Fluid Mech. 1985.17:151~9 Copyright 1985 by Annual Reviews Inc. All rights reserved AERODYNAMICS SPORTS BALLS OF Rabindra 1 D. Mehta Aerodynamics Research Branch, NASA Ames Research Center, Moffett

### Available online at ScienceDirect. Procedia Engineering 112 (2015 )

Available online at www.sciencedirect.com ciencedirect Procedia ngineering 112 (2015 ) 443 448 7th Asia-Pacific Congress on ports Technology, APCT 2015 Kinematics of arm joint motions in basketball shooting

### ScienceDirect. Aerodynamics of ribbed bicycle racing helmets

Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 72 ( 201 ) 91 9 The 201 conference of the International Sports Engineering Association Aerodynamics of ribbed bicycle racing

### THE BRIDGE COLLAPSED IN NOVEMBER 1940 AFTER 4 MONTHS OF ITS OPENING TO TRAFFIC!

OUTLINE TACOMA NARROWS BRIDGE FLOW REGIME PAST A CYLINDER VORTEX SHEDDING MODES OF VORTEX SHEDDING PARALLEL & OBLIQUE FLOW PAST A SPHERE AND A CUBE SUMMARY TACOMA NARROWS BRIDGE, USA THE BRIDGE COLLAPSED

### Uncontrolled copy not subject to amendment. Principles of Flight

Uncontrolled copy not subject to amendment Principles of Flight Principles of Flight Learning Outcome 1: Know the principles of lift, weight, thrust and drag and how a balance of forces affects an aeroplane

### OPTIMIZATION OF SINGLE STAGE AXIAL FLOW COMPRESSOR FOR DIFFERENT ROTATIONAL SPEED USING CFD

http:// OPTIMIZATION OF SINGLE STAGE AXIAL FLOW COMPRESSOR FOR DIFFERENT ROTATIONAL SPEED USING CFD Anand Kumar S malipatil 1, Anantharaja M.H 2 1,2 Department of Thermal Power Engineering, VTU-RO Gulbarga,

### Available online at ScienceDirect. Procedia Engineering 112 (2015 )

Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 112 (2015 ) 540 545 7th Asia-Pacific Congress on Sports Technology, APCST 2015 Movement variability of professional pool billiards

### Wind loads investigations of HAWT with wind tunnel tests and site measurements

loads investigations of HAWT with wind tunnel tests and site measurements Shigeto HIRAI, Senior Researcher, Nagasaki R&D Center, Technical Headquarters, MITSUBISHI HEAVY INDSUTRIES, LTD, Fukahori, Nagasaki,

### Figure 1 Schematic of opposing air bearing concept

Theoretical Analysis of Opposing Air Bearing Concept This concept utilizes air bearings to constrain five degrees of freedom of the optic as shown in the figure below. Three pairs of inherently compensated

### Kick precision and spin rate in drop and torpedo punts

Available online at www.sciencedirect.com Procedia Engineering 60 ( 2013 ) 448 452 6 th Asia-Pacific Congress on Sports Technology (APCST) Kick precision and spin rate in drop and torpedo punts Franz Konstantin

### An investigation of bat durability by wood species

Available online at www.sciencedirect.com Procedia Engineering 34 (2012 ) 427 432 9 th Conference of the International Sports Engineering Association (ISEA) An investigation of bat durability by wood species

### Numerical and Experimental Investigations of Lift and Drag Performances of NACA 0015 Wind Turbine Airfoil

International Journal of Materials, Mechanics and Manufacturing, Vol. 3, No., February 2 Numerical and Experimental Investigations of Lift and Drag Performances of NACA Wind Turbine Airfoil İzzet Şahin

### EFFECT OF CORNER CUTOFFS ON FLOW CHARACTERISTICS AROUND A SQUARE CYLINDER

EFFECT OF CORNER CUTOFFS ON FLOW CHARACTERISTICS AROUND A SQUARE CYLINDER Yoichi Yamagishi 1, Shigeo Kimura 1, Makoto Oki 2 and Chisa Hatayama 3 ABSTRACT It is known that for a square cylinder subjected

### Increasing the power output of the Darrieus Vertical Axis Wind Turbine

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36. Increasing the power output of the Darrieus Vertical Axis Wind Turbine R. Ramkissoon 1 and K. Manohar

### Induced Drag Reduction for Modern Aircraft without Increasing the Span of the Wing by Using Winglet

International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:10 No:03 49 Induced Drag Reduction for Modern Aircraft without Increasing the Span of the Wing by Using Winglet Mohammad Ilias

### STUDIES ON THE OPTIMUM PERFORMANCE OF TAPERED VORTEX FLAPS

ICAS 2000 CONGRESS STUDIES ON THE OPTIMUM PERFORMANCE OF TAPERED VORTEX FLAPS Kenichi RINOIE Department of Aeronautics and Astronautics, University of Tokyo, Tokyo, 113-8656, JAPAN Keywords: vortex flap,

### High Swept-back Delta Wing Flow

Advanced Materials Research Submitted: 2014-06-25 ISSN: 1662-8985, Vol. 1016, pp 377-382 Accepted: 2014-06-25 doi:10.4028/www.scientific.net/amr.1016.377 Online: 2014-08-28 2014 Trans Tech Publications,

### THE FLUID MECHANICS OF SPORTS BALLS Jon Fichtelman Freshmen Learning Center Vero Beach, Florida

THE FLUID MECHANICS OF SPORTS BALLS Jon Fichtelman Freshmen Learning Center Vero Beach, Florida Abstract. The objective of this project is to determine what principles of fluid dynamics influence the performance

### 1. A tendency to roll or heel when turning (a known and typically constant disturbance) 2. Motion induced by surface waves of certain frequencies.

Department of Mechanical Engineering Massachusetts Institute of Technology 2.14 Analysis and Design of Feedback Control Systems Fall 2004 October 21, 2004 Case Study on Ship Roll Control Problem Statement:

### Available online at ScienceDirect. Procedia Engineering 126 (2015 )

Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 126 (2015 ) 542 548 7th International Conference on Fluid Mechanics, ICFM7 Terrain effects on characteristics of surface wind

### AERODYNAMICS OF TEXTILES FOR ELITE CYCLIST

Proceedings of the International Conference on Mechanical Engineering 2009 (ICME2009) 26-28 December 2009, Dhaka, Bangladesh ICME09- AERODYNAMICS OF TEXTILES FOR ELITE CYCLIST Harun Chowdhury, Firoz Alam,

### DESIGN AND CHARACTERISTICS OF A LARGE BOUNDARY- LAYER WIND TUNNEL WITH TWO TEST SECTIONS

The Seventh Asia-Pacific Conference on Wind Engineering, November 8-12, 2009, Taipei, Taiwan DESIGN AND CHARACTERISTICS OF A LARGE BOUNDARY- LAYER WIND TUNNEL WITH TWO TEST SECTIONS Kai Chen 1, Xin-Yang

### Determination of the wind pressure distribution on the facade of the triangularly shaped high-rise building structure

Determination of the wind pressure distribution on the facade of the triangularly shaped high-rise building structure Norbert Jendzelovsky 1,*, Roland Antal 1 and Lenka Konecna 1 1 STU in Bratislava, Faculty

### Study on the Shock Formation over Transonic Aerofoil

Advances in Aerospace Science and Applications. ISSN 2277-3223 Volume 3, Number 2 (2013), pp. 113-118 Research India Publications http://www.ripublication.com/aasa.htm Study on the Shock Formation over

### FLOW CONSIDERATIONS IN INDUSTRIAL SILENCER DESIGN

FLOW CONSIDERATIONS IN INDUSTRIAL SILENCER DESIGN George Feng, Kinetics Noise Control, Inc., 3570 Nashua Drive, Mississauga, Ontario Vadim Akishin, Kinetics Noise Control, Inc., 3570 Nashua Drive, Mississauga,

### AIRFOIL PROFILE OPTIMIZATION OF AN AIR SUCTION EQUIPMENT WITH AN AIR DUCT

THERMAL SCIENCE, Year 2015, Vol. 19, No. 4, pp. 1217-1222 1217 AIRFOIL PROFILE OPTIMIZATION OF AN AIR SUCTION EQUIPMENT WITH AN AIR DUCT by Li QIU a,b, Rui WANG a,*, Xiao-Dong CHEN b, and De-Peng WANG

### Aerodynamically Efficient Wind Turbine Blade S Arunvinthan 1, Niladri Shekhar Das 2, E Giriprasad 3 (Avionics, AISST- Amity University, India)

International Journal of Engineering Science Invention ISSN (Online): 2319 6734, ISSN (Print): 2319 6726 Volume 3 Issue 4ǁ April 2014ǁ PP.49-54 Aerodynamically Efficient Wind Turbine Blade S Arunvinthan

### EDEXCEL NATIONALS UNIT 6 MECHANICAL PRINCIPLES and APPLICATIONS. ASSIGNMENT No. 4

EDEXCEL NATIONALS UNIT 6 MECHANICAL PRINCIPLES and APPLICATIONS ASSIGNMENT No. 4 NAME: I agree to the assessment as contained in this assignment. I confirm that the work submitted is my own work. Signature

### Preliminary Analysis of Drag Reduction for The Boeing

Preliminary Analysis of Drag Reduction for The Boeing 747-400 By: Chuck Dixon, Chief Scientist, Vortex Control Technologies LLC 07. 31. 2012 Potential for Airflow Separation That Can Be Reduced By Vortex

### External Pressure Coefficients on Saw-tooth and Mono-sloped Roofs

External Pressure Coefficients on Saw-tooth and Mono-sloped Roofs Authors: Bo Cui, Ph.D. Candidate, Clemson University, 109 Lowry Hall, Clemson, SC 9634-0911, boc@clemson.edu David O. Prevatt, Assistant

### Available online at ScienceDirect. Procedia Engineering 147 (2016 ) 20 25

Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 147 (2016 ) 20 25 11th conference of the International Sports Engineering Association, ISEA 2016 The use of vortex generators

### ME 239: Rocket Propulsion. Forces Acting on a Vehicle in an Atmosphere (Follows Section 4.2) J. M. Meyers, PhD

ME 239: Rocket Propulsion Forces Acting on a Vehicle in an Atmosphere (Follows Section 4.2) J. M. Meyers, PhD 1 Commonly acting forces on a vehicle flying in a planetary atmosphere: Thrust Aerodynamic

### Improved Aerodynamic Characteristics of Aerofoil Shaped Fuselage than that of the Conventional Cylindrical Shaped Fuselage

International Journal of Scientific & Engineering Research Volume 4, Issue 1, January-213 1 Improved Aerodynamic Characteristics of Aerofoil Shaped Fuselage than that of the Conventional Cylindrical Shaped

### Kinematics-Projectiles

1. A volleyball hit into the air has an initial speed of 10 meters per second. Which vector best represents the angle above the horizontal that the ball should be hit to remain in the air for the greatest

### Physics of Baseball & Softball

Physics of Baseball & Softball Rod Cross Physics of Baseball &Softball ABC Rod Cross School of Physics University of Sydney Sydney, New South Wales Australia cross@physics.usyd.edu.au ISBN 978-1-4419-8112-7

### Analysis of Wind Turbine Blade

International Journal of Current Engineering and Technology E-ISSN 2277 4106, P-ISSN 2347-5161 2014 INPRESSCO, All Rights Reserved Available at http://inpressco.com/category/ijcet Research Article Analysis

### and its weight (in newtons) when located on a planet with an acceleration of gravity equal to 4.0 ft/s 2.

1.26. A certain object weighs 300 N at the earth's surface. Determine the mass of the object (in kilograms) and its weight (in newtons) when located on a planet with an acceleration of gravity equal to

### Lift for a Finite Wing. all real wings are finite in span (airfoils are considered as infinite in the span)

Lift for a Finite Wing all real wings are finite in span (airfoils are considered as infinite in the span) The lift coefficient differs from that of an airfoil because there are strong vortices produced

### Biomechanics Sample Problems

Biomechanics Sample Problems Forces 1) A 90 kg ice hockey player collides head on with an 80 kg ice hockey player. If the first person exerts a force of 450 N on the second player, how much force does

### Kinematic Differences between Set- and Jump-Shot Motions in Basketball

Proceedings Kinematic Differences between Set- and Jump-Shot Motions in Basketball Hiroki Okubo 1, * and Mont Hubbard 2 1 Department of Advanced Robotics, Chiba Institute of Technology, 2-17-1 Tsudanuma,

### University of Bristol - Explore Bristol Research. Publisher's PDF, also known as Version of record

Liu, X., Azarpeyvand, M., & Joseph, P. (2015). On the acoustic and aerodynamic performance of serrated airfoils. Paper presented at The 22nd International Congress on Sound and Vibration, Florence, France.

### Dynamics of bubble rising at small Reynolds numbers

MATEC Web of Conferences 3, 01004 ( 015) DOI: 10.1051/ matecconf/ 015301004 C Owned by the authors, published by EDP Sciences, 015 Dynamics of bubble rising at small Reynolds numbers Vladimir Arkhipov

### The Effect of Von Karman Vortex Street on Building Ventilation

The Effect of Von Karman Vortex Street on Building Ventilation P.Praveen Kumar Abstract This paper deals with the utilisation of the von Karman vortex street principle to maximise air flow into buildings.

### PRE-TEST Module 2 The Principles of Flight Units /60 points

PRE-TEST Module 2 The Principles of Flight Units 1-2-3.../60 points 1 Answer the following questions. (20 p.) moving the plane (4) upward / forward. Opposed to that is 1. What are the names of the four

### Static Extended Trailing Edge for Lift Enhancement: Experimental and Computational Studies

Static Extended Trailing Edge for Lift Enhancement: Experimental and Computational Studies T. Liu, J. Montefort, W. Liou Western Michigan University Kalamazoo, MI 49008 and Q. Shams NASA Langley Research

### A comparison between timed and IMU captured Nordic ski glide tests

Available online at www.sciencedirect.com Procedia Engineering 34 (202 ) 397 402 9 th Conference of the International Sports Engineering Association (ISEA) A comparison between timed and IMU captured Nordic

### International Journal of Technical Research and Applications e-issn: , Volume 4, Issue 3 (May-June, 2016), PP.

DESIGN AND ANALYSIS OF FEED CHECK VALVE AS CONTROL VALVE USING CFD SOFTWARE R.Nikhil M.Tech Student Industrial & Production Engineering National Institute of Engineering Mysuru, Karnataka, India -570008

### Design of a Solid Wall Transonic Wind Tunnel

Design of a Solid Wall Transonic Wind Tunnel David Wall * Auburn University, Auburn, Alabama, 36849 A solid wall transonic wind tunnel was designed with optical access from three sides to allow for flow

### Comparing the Performance of Baseball Bats

Comparing the Performance of Baseball Bats Margaret Raabe Physics Department, The College of Wooster, Wooster, Ohio 44691, USA (Dated: May 11, 2011) Experimental analysis is done on three different types

### Ground Forces Impact on Release of Rotational Shot Put Technique

Brigham Young University BYU ScholarsArchive All Theses and Dissertations 2014-12-01 Ground Forces Impact on Release of Rotational Shot Put Technique Niklas B. Arrhenius Brigham Young University - Provo

### Investigation on Divergent Exit Curvature Effect on Nozzle Pressure Ratio of Supersonic Convergent Divergent Nozzle

RESEARCH ARTICLE OPEN ACCESS Investigation on Divergent Exit Curvature Effect on Nozzle Pressure Ratio of Supersonic Convergent Divergent Nozzle Shyamshankar.M.B*, Sankar.V** *(Department of Aeronautical

### Available online at ScienceDirect. Procedia Engineering 161 (2016 )

Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 161 (216 ) 1845 1851 World Multidisciplinary Civil Engineering-Architecture-Urban Planning Symposium 216, WMCAUS 216 Experimental

### Available online at Procedia Engineering 200 (2010) (2009)

Available online at www.sciencedirect.com Procedia Engineering 200 (2010) (2009) 000 000 2505 2510 Procedia Engineering www.elsevier.com/locate/procedia 8 th Conference of the International Sports Engineering

### Fluid Mechanics of Cricket Ball Swing

19 th Australasian Fluid Mechanics Conference Melbourne, Australia 8-11 December 2014 Fluid Mechanics of Cricket Ball Swing R. D. Mehta Sports Aerodynamics Consultant Mountain View, CA 94043, USA Abstract

### Practice Test: Vectors and Projectile Motion

ame: Practice Test: Vectors and Projectile Motion Part A: Multiple Choice [15 points] 1. A projectile is launched at an angle of 30 0 above the horizontal. eglecting air resistance, what are the projectile

### A numerical Euler-Lagrange method for bubble tower CO2 dissolution modeling

A numerical Euler-Lagrange method for bubble tower CO2 dissolution modeling Author: Daniel Legendre & Prof. Ron Zevenhoven Åbo Akademi University Thermal and Flow Engineering Laboratory Turku, Finland

### Georgian University GEOMEDI. Abstract. In this article we perform theoretical analysis of long jumps with the purpose to find

On the t Influence of Air Resistance and Wind during Long Jump Egoyan A. E. ( alex1cen@yahoo.com ), Khipashvili I. A. Georgian University GEOMEDI Abstract. In this article we perform theoretical analysis

### Abstract. 1 Introduction

Developments in modelling ship rudder-propeller interaction A.F. Molland & S.R. Turnock Department of Ship Science, University of Southampton, Highfield, Southampton, S017 IBJ, Hampshire, UK Abstract A

### A Scientific Approach for Diagnosing a Junior Tennis Player s Swing and Determining Optimum Racquet Parameters

ISSN 1750-9823 (print) International Journal of Sports Science and Engineering Vol. 07 (2013) No. 01, pp. 060-064 A Scientific Approach for Diagnosing a Junior Tennis Player s Swing and Determining Optimum

### The Aerodynamic Design and Investigation of Loading Distribution of a Mixed Flow Compressor

Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 00 (2014) 000 000 www.elsevier.com/locate/procedia APISAT2014, 2014 Asia-Pacific International Symposium on Aerospace Technology,

### EXPERIMENTAL AND ANALYTICAL INVESTIGATION OF THE EFFECT OF BODY KIT USED WITH SALOON CARS IN BRUNEI DARUSSALAM

EXPERIMENTAL AND ANALYTICAL INVESTIGATION OF THE EFFECT OF BODY KIT USED WITH SALOON CARS IN BRUNEI DARUSSALAM M.G., Yazdani, H. Ullah, T. Aderis and R. Zainulariffin, Faculty of Engineering, Institut

### II.E. Airplane Flight Controls

References: FAA-H-8083-3; FAA-8083-3-25 Objectives Key Elements Elements Schedule Equipment IP s Actions SP s Actions Completion Standards The student should develop knowledge of the elements related to

### Aerofoil Design for Man Powered Aircraft

Man Powered Aircraft Group Aerofoil Design for Man Powered Aircraft By F. X. Wortmann Universitat Stuttgart From the Second Man Powered Aircraft Group Symposium Man Powered Flight The Way Ahead 7 th February

### A Teacher s Utilization Guide.

A Teacher s Utilization Guide www.pbs4549.org/baseball Table of Contents Credits...4 Introduction...5 108 Stitches: The Physics in Baseball...7 Video Overviews...8 Content Standards...9 Correlated Ohio

### Journal of Aeronautics & Aerospace

Journal of Aeronautics & Aerospace Engineering Journal of Aeronautics & Aerospace Engineering Landell-Mills, J Aeronaut Aerospace Eng 2017, 6:2 DOI: 10.4172/2168-9792.1000189 Research Article Open Access