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McAllister, Jeffrey, Calliandra Stuffle, Yasa Sampurno, Dale Hetherington, Jon Sierra Suarez, Leonard Borucki, and Ara Philipossian. "Effect of Conditioner Type and Downforce, and Pad Surface Micro-Texture on SiO2 Chemical Mechanical Planarization Performance." Micromachines 10, no. 4 (April 18, 2019): 258. http://dx.doi.org/10.3390/mi10040258.
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Based on a previous work where we investigated the effect of conditioner type and downforce on the evolution of pad surface micro-texture during break-in, we have chosen certain break-in conditions to carry out subsequent blanket SiO2 wafer polishing studies. Two different conditioner discs were used in conjunction with up to two different conditioning downforces. For each disc-downforce combination, mini-marathons were run using SiO2 wafers. Prior to polishing, each pad was broken-in for 30 min with one of the conditioner-downforce combinations. The goal of this study was to polish wafers after this break-in to see how the polishing process behaved immediately after break-in. One of the discs used in this study produced similar micro-texture results at both downforces, which echoed the results seen in the mini-marathon. When comparing the different polishing results obtained from breaking-in the pad with the different discs used in this study, the coefficient of friction (COF) and SiO2 removal rate (RR) were uncorrelated in all cases. However, the use of different discs resulted in different COF and RR trends. The uncorrelated COF and RR, as well as the differing trends, were explained by pad micro-texture results (i.e. the differing amount of fractured, poorly supported pad asperity summits).
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Cross, A., and S. Gough. "Monitoring Downforce." Strain 36, no. 2 (May 2000): 49–50. http://dx.doi.org/10.1111/j.1475-1305.2000.tb01172.x.
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Virk, Simerjeet, Wesley Porter, John Snider, Glen Rains, Changying Li, and Yangxuan Liu. "Cotton Emergence and Yield Response to Planter Depth and Downforce Settings in Different Soil Moisture Conditions." AgriEngineering 3, no. 2 (May 28, 2021): 323–38. http://dx.doi.org/10.3390/agriengineering3020022.
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US cotton producers are motivated to optimize planter performance to ensure timely and uniform stand establishment early in the season, especially when planting in sub-optimal field conditions. Field studies were conducted in 2017, 2018 and 2019 to evaluate the effect of seeding depth and planter downforce on crop emergence and yield in cotton planted in different soil moisture conditions. Field conditions representative of dry, normal and wet soil moisture conditions were attained by applying 0, 1.27 and 2.54 cm of irrigation within the same field. Two cotton cultivars (representing a small-seeded and a large-seeded cultivar, 9259–10,582 and 11,244–14,330 seeds kg−1, respectively), were planted at seeding depths of 1.3, 2.5 and 3.8 cm with each seeding depth paired with three different planter downforces of 0, 445 and 890 N in each block. Cotton was planted in plots that measured 3.66 m (four-rows) wide by 10.67 m long. Results indicated that crop emergence was affected by the seeding depth across most field conditions and higher crop emergence was observed in the large-seeded cultivar at 1.3 and 3.8 cm seeding depths in dry and wet field conditions, respectively. Lint yield was also higher for the large-seeded cultivar at the 3.8 cm seeding depth across all field conditions in 2017, and in dry field conditions in 2018. Planter downforce effect on crop emergence varied among the cultivars where the large-seeded cultivar exhibited higher crop emergence than the small-seeded cultivar at 445 and 890 N downforce. Planter downforce of 445 N yielded greater than the 0 and 890 N treatment in dry field conditions in 2017. The study results suggest that matching planter depth and downforce settings for prevalent soil moisture conditions at planting along with appropriate cultivar selection can help in achieving optimal emergence and yield in cotton.
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Virk, Simerjeet S., Wesley M. Porter, John L. Snider, Jared R. Whitaker, Glen C. Rains, and Changying C. Li. "Influence of Seeding Rate, Planter Downforce and Cultivar on Crop Emergence and Yield in Singulated and Hill-Dropped Cotton." Journal of Cotton Science 24, no. 3 (2020): 137–47. http://dx.doi.org/10.56454/wrjs4850.
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Cotton (Gossypium hirsutum L.) growers are motivated to reduce seeding rates due to increased technology fees associated with improved transgenic cotton cultivars. Advances in planting machinery have improved precision of seed metering and seed placement in recent years. A two-year study was conducted to evaluate the effect of seeding rate, planter downforce, and cultivar on crop emergence and lint yield in cotton planted as singulated and hill-drop (two seed hill-1) configuration. Study treatments consisted of two seeding rates (71,660 and 107,490 seed ha-1), two to three planter downforces (0, 445 and 890 N in 2017; 0 and 890 N in 2018) and two cotton cultivars (representing a large-seeded and small-seeded cultivar, 9,259 - 10,582 and 11,244 - 14,330 seed kg-1, respectively) arranged in a strip-split plot design in both seeding configurations. Crop emergence and lint yield in the middle two rows (four-row plots) were measured to evaluate treatment effects among seeding configurations. Results showed that seeding rate and cultivar did not affect (p>0.05) crop emergence and lint yield in both singulated and hill-drop cotton. Crop emergence varied between the two years due to differences in field tillage conditions. Planter downforce affected crop emergence in singulated cotton but not in hill-drop cotton during both years. Field tillage conditions also influenced downforce effect on crop emergence. Selection of an optimal planter downforce had more significant effect (p<0.05) on singulated cotton than hill-dropped cotton. Results showed that large-seeded cultivars can be utilized to attain a high crop emergence early in the season which can help in minimizing production risks associated with poor stand establishment. High seed and technology fees incurred by growers can be effectively reduced by planting lower seeding rates - given an adequate stand establishment is attained using appropriate planter setup including downforce and cultivar selection.
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Poncet, Aurelie M., John P. Fulton, Timothy P. McDonald, Thorsten Knappenberger, Joey N. Shaw, and Rees W. Bridges. "Effect of Heterogeneous Field Conditions on Corn Seeding Depth Accuracy and Uniformity." Applied Engineering in Agriculture 34, no. 5 (2018): 819–30. http://dx.doi.org/10.13031/aea.12238.
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Abstract. Optimization of planter performance such as uniform seeding depth is required to maximize crop yield potential. Typically, seeding depth is manually adjusted prior to planting by selecting a row-unit depth and a row-unit downforce to ensure proper seed-soil contact. Once set, row-unit depth and downforce are usually not adjusted again for a field although soil conditions may vary. Optimization of planter performance requires automated adjustments of planter settings to varying soil conditions, but development of precision technologies with such capabilities requires a better understanding of soil-planter interactions. The objective of this study was to evaluate seeding depth response to varying soil conditions between and within fields and to discuss implications for development and implementation of active planting technologies. A 6-row John Deere MaxEmerge Plus planter equipped with heavy-duty downforce springs was used to plant corn ( L.) in central Alabama during the 2014 and 2015 growing seasons. Three depths (4.4, 7.0, and 9.5 cm) and three downforces (corresponding to an additional row-unit weight of 0.0, 1.1, and 1.8 kN) were selected to represent common practices. Depth and downforce were not readjusted between fields and growing seasons. Seeding depth was measured after emergence. Corn seeding depth significantly varied with heterogeneous soil conditions between and within fields and the planter failed to achieve uniform seeding depth across a field. Differences in corn seeding depth between fields and growing seasons were as high as 2.1 cm for a given depth and downforce combination. Corn seeding depth significantly co-varied with field elevation but not with volumetric soil water content. Seeding depth varied with elevation at a rate ranging from -0.1 cm/m to -0.6 cm/m. Seeding depth co-variation to field elevation account for some but not all site-specific seeding depth variability identified within each field trial. These findings provide a better understanding of site-specific seeding depth variability and issues to address for the development of site-specific planting technologies to control seeding depth accuracy and improve uniformity. Keywords: Depth control, Downforce, Planter, Precision agriculture, Seeding depth, Uniformity.
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Strasser, Ryan, Sylvester A. Badua, Ajay Sharda, and Matthias Rothmund. "Development of a Test Stand to Quantify the Response of a Planter’s Automatic Downforce Control System." Transactions of the ASABE 64, no. 5 (2021): 1533–43. http://dx.doi.org/10.13031/trans.14047.
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HighlightsThe developed downforce test stand simulated varying disc loads based on actual field data.The planter’s downforce control system was able to maintain the target gauge wheel load 94% of the time.The planter’s downforce control system managed disc load variations of up to 667 N within 1.3 s.Abstract. In recent years, precision planters have incorporated automatic control of the row unit downforce to reduce sidewall soil compaction, maintain proper seeding depth, and control row unit ride quality. By applying an appropriate row unit downforce, more uniform emergence and increased yield can be obtained. However, little research exists on evaluating the response and accuracy of downforce control systems during planting. Therefore, the objectives of this study were to (1) develop a laboratory-scale row unit downforce test stand and (2) use the test stand to evaluate the downforce control system response time and the load distribution between the gauge wheels, opening discs, and closing wheels using simulation scenarios based on real-world soil and terrain data. The downforce test stand was able to distribute the applied downforce to the row unit gauge wheels, opening discs, and closing wheels. It was also capable of varying the row unit ride height. The simulation scenarios using the test stand showed that the downforce control system maintained the target gauge wheel load (GWL) of 379 N within ±223 N for more than 94% of the time during all simulations. The downforce control system was also able to manage the GWL within 1.3 s for disc load variations up to 667 N. Keywords: Automatic downforce control, Downforce test stand, Gauge wheel load, Simulation.
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Konwar Roy, Sidhant, and Abhishek Mahesh Sharma. "Effects of Aerodynamic downforce on Vehicle Control and Stability." Journal of University of Shanghai for Science and Technology 23, no. 11 (November 6, 2021): 78–85. http://dx.doi.org/10.51201/jusst/21/10861.
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This paper deals with the analysis of vehicle handling with the variation of downforce. A vehicle with aero package were taken and the values of aerodynamic downforce and front downforce distribution for different front and rear ride heights were taken. This was followed by the generation of yaw moment diagram at original ground clearance of 30mm. Aero map data were collected and individual yaw moment diagrams were collected from which vehicle handling parameters are noted. Different contour plots were made to understand the variation of vehicle handling with different ride heights (aerodynamics downforce and downforce distribution). The paper concludes with the sensitivity study where effects of aerodynamic downforce were recorded on vehicle control and stability.
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Li, Baosheng, Yu Tan, Jian Chen, Xingxing Liu, and Shenghui Yang. "Precise Active Seeding Downforce Control System Based on Fuzzy PID." Mathematical Problems in Engineering 2020 (May 12, 2020): 1–10. http://dx.doi.org/10.1155/2020/5123830.
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Soil compaction is an important procedure of precision seeding operation. In this paper, a precise downforce control system based on fuzzy PID was proposed in order to improve the quality of the soil compaction and the accuracy of setting working parameters. The conventional mechanism of seeders for soil compaction was optimised. The compressing spring of the compaction mechanism was replaced by a linear motor, which is actively controlled to adjust downforce in real time. A force sensor was connected in series with the linear motor to detect the actual downforce from a press wheel acting on soil. The detected downforce was employed as feedback for the fuzzy PID model. A slave real-time control system was constructed by using an STM32 microcontroller. A user interface was designed for the portable master computer system based on the ForLinx embedded platform to facilitate the setting of target downforce and display the actual downforce in real time. Meanwhile, it was able to adjust the system for different operating requirements, such as soil stiffness, moisture, and crop species. Experiments were conducted on a soil bin, and the results indicated that the active control system has better performance than the conventional passive system in downforce control. The downforce was stable with a variance less than 2.6% under different conditions, and it was 8.11% less than the conventional passive system.
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Poncet, Aurelie M., John P. Fulton, Timothy P. McDonald, Thorsten Knappenberger, and Joey N. Shaw. "Corn Emergence and Yield Response to Row-unit Depth and Downforce for Varying Field Conditions." Applied Engineering in Agriculture 35, no. 3 (2019): 399–408. http://dx.doi.org/10.13031/aea.12408.
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Abstract. Optimum row-crop planter seeding depth performance is required to place seeds within proper soil conditions to ensure quick germination and maximize the likelihood of uniform emergence. Seeding depth is adjusted prior to planting by selecting a row-unit depth, followed by the adjustment of a row-unit downforce for proper seed-soil contact. Optimum row-unit depth and downforce settings required to maintain a consistent seeding depth are variable. The objective of this study was to evaluate corn ( L) emergence and yield response to row-unit depth and downforce in changing field conditions between sites and growing seasons. Corn was planted with a 6-row John Deere MaxEmerge Plus planter equipped with heavy duty downforce springs. The experiment was conducted in 2014 and 2015 in Central Alabama for non-irrigated corn. Two fields, three row-unit depths (4.4, 7.0, and 9.5 cm), and three row-unit downforce settings (0.0, 1.1, and 1.8 kN) were evaluated. Emergence was measured at 75 and 100 Growing Degree Days (GDDs). Yield was measured using a yield monitor installed on the combine harvester. Corn emergence was mainly affected by changes in weather conditions. Row-unit depth and downforce did not affect corn emergence in warmer weather conditions but the 4.4 cm row-unit depth resulted in more emergence than the other row-unit depth settings in cooler weather conditions. Yield ranged from 8,000 to 13,000 kg ha-1 across treatments and yield was mostly affected by changing growing conditions between fields and growing seasons. Plant population significantly varied with treatments, but lower plant populations did not always result in lower corn yields. These findings provided a better understanding of corn emergence and yield response to row-unit depth and downforce in varying field conditions. Keywords: Corn, Depth, Downforce, Emergence, Maize, Planter, Yield.
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Baltagiu, Daniel, Radu Gaiginschi, Radu Drosescu, and Ioan Damian. "A New Electric Drive System for a Disc Brake System Used in the Vehicle, Experimental Stand." Applied Mechanics and Materials 659 (October 2014): 139–44. http://dx.doi.org/10.4028/www.scientific.net/amm.659.139.
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Papers present a new solution for achieving downforce to a brake disc, using a drive gear and ball screw-nut, which the construction adopted, allows moving ball-screw and making the necessary downforce for breaking. The stand includes downforce creating system required by deceleration, and is equipped with a plurality of sensors to determine the following parameters. Measurement of downforce-ring load cell, displacement in the running drive-pressure transducer, mechanism decoupling travel-differential inductive transducer, electrical motor and gear drive mechanism speed-speed transducer, and electric drive motor torque-lamellar load cell. These transducers allow the control of screw ball to realize the forces that are acting on the brake linings in order to control the speed of the vehicle. Using this construction, brake actuation can get higher quality reactions in brake systems.
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Zhang, Xin, Willem Toet, and Jonathan Zerihan. "Ground Effect Aerodynamics of Race Cars." Applied Mechanics Reviews 59, no. 1 (January 1, 2006): 33–49. http://dx.doi.org/10.1115/1.2110263.
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We review the progress made during the last 30years on ground effect aerodynamics associated with race cars, in particular open wheel race cars. Ground effect aerodynamics of race cars is concerned with generating downforce, principally via low pressure on the surfaces nearest to the ground. The “ground effect” parts of an open wheeled car’s aerodynamics are the most aerodynamically efficient and contribute less drag than that associated with, for example, an upper rear wing. While drag reduction is an important part of the research, downforce generation plays a greater role in lap time reduction. Aerodynamics plays a vital role in determining speed and acceleration (including longitudinal acceleration but principally cornering acceleration), and thus performance. Attention is paid to wings and diffusers in ground effect and wheel aerodynamics. For the wings and diffusers in ground effect, major physical features are identified and force regimes classified, including the phenomena of downforce enhancement, maximum downforce, and downforce reduction. In particular the role played by force enhancement edge vortices is demonstrated. Apart from model tests, advances and problems in numerical modeling of ground effect aerodynamics are also reviewed and discussed. This review article cites 89 references.
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Dominy, J., and D. N. Bulman. "An Active Suspension for a Formula One Grand Prix Racing Car." Journal of Dynamic Systems, Measurement, and Control 107, no. 1 (March 1, 1985): 73–79. http://dx.doi.org/10.1115/1.3140710.
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During 1982, Formula 1 racing cars generated very high downforces by the use of “ground effect” aerodynamics. Such cars required very stiff suspensions to maintain a reasonably constant ride height with the result that the slightest bump unsettled the chassis and reduced cornering speeds. A semi-active suspension would have been capable of withstanding the variations in downforce while remaining “soft” to rapid road inputs. This paper proposes such a system and decribes an analysis of its dynamic responses. It demonstates that it is able to maintain a sensibly constant ride height and attitude during cornering, braking, and acceleration, while minimizing the chassis response to individual bumps.
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Shi, Kailai. "An Active Suspension System Design for a Racing Car." Journal of Physics: Conference Series 2216, no. 1 (March 1, 2022): 012018. http://dx.doi.org/10.1088/1742-6596/2216/1/012018.
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Abstract This paper investigated the PID controller for an active suspension system for a racing car. A two-wheel half-car model is used and simulated in the Simulink environment. This model allows us to have two outputs and separately change the demand ride height of the front axle and the rear axle. Considering it is a racing car, downforce plays an important part in the suspension system and makes it a bit different from a private car that can only produce little downforce that can be ignored. To improve the control quality, a feedforward controller is added to compensate for the downforce.
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Lim, S. J., and M. R. A. Mansor. "Aerodynamic Analysis of F1 IN SCHOOLS™ Car." Journal of the Society of Automotive Engineers Malaysia 1, no. 1 (January 31, 2017): 41–54. http://dx.doi.org/10.56381/jsaem.v1i1.7.
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F1 IN SCHOOLS™ is a worldwide competition that is part of the efforts undertaken by the STEM educational model. In order to increase the performance of the F1 IN SCHOOLS™ car in terms of speed, two important parameters related to aerodynamic analysis are considered - drag coefficient and downforce coefficient. Drag force is a force that acts in the direction that is opposite of the car's motion, thus reducing the car's maximum speed. Meanwhile, sufficient downforce is beneficial to the car model because it allows the car's wheels to remain in contact with the track surface without going off-track. The most important component of a F1 IN SCHOOLS™ car is its front wing since its design has a significant effect on the drag coefficient and downforce coefficient induced by the air flow. Therefore, the objective of this study is to design a front wing that is capable of producing low drag coefficient while maintaining sufficient downforce coefficient. Moreover, this study also aims to examine the method of preventing flow separation at the rear part of the car model. This study will use Autodesk Inventor Professional to create the car mode. The simulation will be run using the STAR CCM+ software. The simulation will also be used to obtain the drag coefficient and downforce coefficient of the car.
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Cao, Xinpeng, Qingjie Wang, Dijuan Xu, Shenghai Huang, Xiuhong Wang, and Longbao Wang. "Design and Analysis of Pneumatic Downforce Regulating Device for No-Till Corn Planter." Agriculture 12, no. 10 (September 21, 2022): 1513. http://dx.doi.org/10.3390/agriculture12101513.
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To avoid the issues of undesired soil compaction and seeding depth variation caused by the downforce fluctuation of the corn no-till planter, the influence of the structural parameters of the air spring on the downforce was researched in this paper, by establishing the gas–solid coupling simulation model of the air spring. The downforce test bench was built to verify the simulation model; the test showed that the vertical output force error of the simulation model was 4.79%, the pitch diameter error was 0.76%, and the pressure error was 5.07%. The cord angle, piston angle and piston diameter were used as influencing factors to carry out single-factor experiments. The influences of structural parameters on downforce were analyzed from four aspects: the vertical output force, the vertical stiffness, the pressure difference and the deformation rate. The results showed that the cord angle reduced the effective area and its change rate during deformation by limiting the radial deformation of the bellow. When the cord angles were 30°, 45° and 60°, the deformation rates were 65.6%, 20.3% and 4.8%, respectively. The cord angle had a positive effect on the vertical output force when the cord angle was in the range of 30~56°, and it had a negative impact in the range of 56~60°. As the cord angle increased, the vertical stiffness decreased. As the piston angle increased, the effective area of the air spring decreased, and the change in internal pressure decreased, reducing its vertical output force and stiffness. The piston diameter had little effect on the internal pressure and deformation rate. It increased the vertical output force and stiffness by increasing the effective area. The structural parameters of the air spring had a significant impact on the stability of the downforce; the structure of the air spring should be optimized according to the downforce demand of the corn no-till planter.
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Wafi, A., M. H. Basha, M. Tasyrif, and M. F. Hamid. "Aerodynamics Analysis of UniMAP Automotive Racing Team Formula SAE race car spoiler via simulation: Effect of Spoiler Size." Journal of Physics: Conference Series 2051, no. 1 (October 1, 2021): 012022. http://dx.doi.org/10.1088/1742-6596/2051/1/012022.
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Abstract Lift force that occurred on a speeding race car will cause the vehicle to lost its stability, traction and speed. Therefore, a car spoiler is installed on a race car to reduce the lift force, making the vehicle more stable. The present work investigated the impact of spoiler size on the drag force and downforce value on the UniART FSAE race car using simulation software. From the results, a larger spoiler size gives the highest downforce compared to other sizes. The downforce and the area of the spoiler showed a directly proportional relationship. The result of drag force led us to conclude drag force increase if the spoiler is mounted at the rear part of the car, however different sizes of spoiler doesn’t seem to have a big effect on the drag force.
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Sriram, P. S., Ashok Gopalarathnam, and Andrew Misenheimer. "High-Downforce Airfoil Design for Motorsports." SAE International Journal of Materials and Manufacturing 5, no. 2 (April 16, 2012): 478–89. http://dx.doi.org/10.4271/2012-01-1168.
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Brune, Philip F., Bradley J. Ryan, Frank Technow, and D. Brenton Myers. "Relating planter downforce and soil strength." Soil and Tillage Research 184 (December 2018): 243–52. http://dx.doi.org/10.1016/j.still.2018.08.003.
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Abid, Muhammad, Hafiz Abdul Wajid, Muhammad Zohair Iqbal, Shayan Najam, Ali Arshad, and Ammad Ahmad. "DESIGN AND ANALYSIS OF AN AERODYNAMIC DOWNFORCE PACKAGE FOR A FORMULA STUDENT RACE CAR." IIUM Engineering Journal 18, no. 2 (December 1, 2017): 212–24. http://dx.doi.org/10.31436/iiumej.v18i2.679.
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This paper presents design of aerodynamic downforce generating devices (front wing, rear wing and diffuser) to enhance the performance of the Formula Student Race Car using numerical and experimental studies. Numerical results using computational fluid dynamics (CFD) studies were primarily validated with the experimental results performed in the wind tunnel. It was concluded that the use of a downforce package can enhance the performance of the vehicle in the competition.
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Shendge, Smit. "Study and Design a Spoiler to Understand Aerodynamics with Various Angle of Attack at Different speeds." International Journal for Research in Applied Science and Engineering Technology 9, no. 8 (August 31, 2021): 2648–56. http://dx.doi.org/10.22214/ijraset.2021.37787.
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Abstract: In this scope of study, various type of spoiler is researched out of which a pedestal spoiler is chosen to design as it generates a very good downforce and also has good aesthetic appeal to it, spoiler is designed considering actual scaled dimensions. Analysis on the designed pedestal spoiler is carried out to get to know how much the downforce is generated and at the same time how much drag coefficient is produced. Also, angle of attack of the spoiler in various degrees (9, 6, 4, 3, 2, 0, -2, - 3, -4, -6, -9, -12, -15) is carried out to know downforce at various angle of attack with various velocity (10, 15, 20, 25, 30, 35, 40, 45, 50) inputs in meter per seconds. After carrying out more than 80 analysis, found that highest downforce generated by the spoiler’s angle of attack is at (-6) degree with a 400 N of downforce and also with low drag. Velocity magnitude contour plot of each angle is provided to understand the air flow around each angle of attack. To validate the results given by the simulation tool a mathematical/analytical calculation are carried out for four angles of attack with a good result and also graphs are plotted for each validation to figure out the variation in them. Observing the validation’s graphs and calculations the difference between computational results and mathematical/analytical results is less than 5% indicating a proper process carried out in simulation and approximately giving realistic values that can be given in a wind tunnel aerodynamic test. Keywords: Spoiler, Aerodynamics, CAD, CFD, Drag coefficient, Lift coefficient, angle of attack.
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Ma’arof, M. I. N., Nurfarah A. Z. Kamarudin, Girma T. Chala, and Timur Izmailov. "Anti-Lift Assessment of Multi-Flap Motorcycle Winglet for Track Usage Via Wind Tunnel Test." International Journal of Emerging Technology and Advanced Engineering 12, no. 4 (April 2, 2022): 39–44. http://dx.doi.org/10.46338/ijetae0422_06.
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Abstract— In motorcycle racing it is important to travel at high speed. However, involuntary lift of the front wheel could occur at high speed of travelling. This results in the loss of traction, stability and control over the motorcycle. This undesired phenomenon could be minimized by adding downforce at the frontal section of the motorcycle. The aim of this study was to generate supplementary downforce via the integration of anti-lift winglet at the frontal section of the motorcycle. This study tested on the effects given by the variation on the numbers of multi-element flaps with respect to anti-lift force generated. The anti-lift winglet assisted the motorcyclist for greater control and stability during high speed of travelling by being planted onto the ground. It was observed that the highest downforce is generated by winglets with the highest number of multi-element flaps. Conclusively, the installation of the winglet on the motorcycle significantly improves control and stability during high speed of travelling by being planted onto the ground. For future studies, other parameters such as the angle of attack for the winglet and the general shape of the winglets could be examined. Keywords— Semi-active winglet, Downforce, Mechanism, Multi-element wing.
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Badua, Sylvester A., Ajay Sharda, Daniel Flippo, and Igancio A. Ciampitti. "Real-Time Gauge Wheel Load Variability of a Row-Crop Planter During Field Operation." Transactions of the ASABE 61, no. 5 (2018): 1517–27. http://dx.doi.org/10.13031/trans.12511.
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Abstract. Planter downforce control allows row units to maintain a target gauge wheel load (GWL) across a range of soil resistance within a field. Downforce control is typically set for a target seed depth and can be implemented either as fixed or by automatic or active control to attain the desired GWL. Recent advances allow for the control of individual row units into sections for improved GWL application. However, little knowledge exists on the spatial variability of GWL, row-to-row GWL variability, and on the recommended GWL control requirements on planters operating in actual field conditions. Therefore, the objectives of this study were to (1) quantify real-time GWL variability across individual row units within a 12-row crop planter programmed to implement a constant downforce control during field operations; (2) evaluate gauge wheel load range (GWLR) across individual row units and within 2-row, 3-row, or 4-row control sections to determine the optimal downforce control section size; and (3) assess the impact of soil texture and soil compaction due to tire tracks on GWL variability. To address these objectives, a 12-row crop planter equipped with hydraulic downforce control was used to plant three fields. The planter was set to plant corn at 5.2 and 5.7 cm depths with fixed target GWL set at 334 ±223 N (111 to 557 N) and GWLR set at 0 to 883 N. A data acquisition system collected real-time GPS, planting speed, GWL, hydraulic pressure, and planter toolbar height data at 10 Hz. Real-time GWL data of individual row units were analyzed to determine the GWL distribution within or outside the set target GWL. Moreover, GWLR was measured in individual row units and across varying control section sizes. Soil electrical conductivity (EC) was measured using a Veris mobile sensor platform. Soil EC was used in defining zones of low, medium, and high textured soil. Results show that GWL was within the target range of 111 to 557 N at 33% of the total planting time across the three fields, and GWLR was within 0 to 441 N at 9% of the total planting time. Results also indicate that a 2-row, 3-row, and 4-row control section could provide GWLR within 0 to 441 N at 76%, 46%, and 28% of the total planting time, respectively. These findings suggest the need for automatic downforce systems with fewer row units per control section to maintain target GWL within an acceptable range for all row units. Regression analyses indicate that soil texture is a significant variable that can influence real-time GWL. Furthermore, compacted soil due to tractor tires contributed to significantly lower GWL. Our data suggest the need for active downforce control to achieve improved GWL uniformity under varying field-operating conditions. Keywords: Gauge wheel load, Planter downforce, Precision planters, Seeding depth, Variability.
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Faiz Paturrahman, Mohamad, Mohd Radzi Abu Mansor, Zambri Harun, and Mohd Anas Mohd Sabri. "Study on the Modification Effect of Side Pot And Diffuser to the Aerodynamics of the F1 IN SCHOOLS Car." International Journal of Engineering & Technology 7, no. 3.17 (August 1, 2018): 123. http://dx.doi.org/10.14419/ijet.v7i3.17.16635.
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The F1 IN SCHOOLS competition was established in 2004 to develop students’ interest towards science, technology, engineering and mathematics (STEM) in the secondary school phase. The application of aerodynamics is one of the important aspects studied during this phase. There are two factors that must be considered in the analysis affecting the aerodynamic performance of the car, namely the maximum velocity of the drag coefficient and the downforce coefficient. The F1 IN SCHOOLS car velocity is mainly related to its aerodynamic design and features. The objective of this paper is to study the effect of different side pot and diffuser designs that are capable of producing a low drag coefficient while maintaining a sufficient downforce coefficient. The simulation study was conducted using CFD STAR CCM+ software. The results will help to produce a miniature car that will meet two important criteria of low drag coefficient and sufficient downforce coefficient.
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Pugliese, Aldo, Zhi Gang Yang, and Qi Liang Li. "CFD Research and Investigation of 2011 P4/5 Competition Rear Wing." Applied Mechanics and Materials 275-277 (January 2013): 665–71. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.665.
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In order to analyze the influence of the rear wing of a competition race car on the aerodynamics of the whole vehicle, computational fluid dynamics simulations have been performed. Rear wing is set by two elements, a main plate and a flap. Their relative position and the angle of attack of these elements influence the aero- performances in terms of downforce and drag generated; 12 different configurations have been generated, modifying the angle of attack and the slot gap. 3D mesh has been generated from the geometrical model of the vehicle, and air flow around the vehicle and on the rear wing has been evaluated through a CFD commercial software. It has been proved that steeper angles of attack of the mainplate and of the flap contribute to generate more downforce until a certain point; when angle of attack reaches a critical value, the downforce no longer increases and the drag still keep high values.
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Porcar, Laura, Willem Toet, and Pedro Javier Gamez-Montero. "Study of the Effect of Vertical Airfoil Endplates on Diffusers in Vehicle Aerodynamics." Designs 5, no. 3 (July 21, 2021): 45. http://dx.doi.org/10.3390/designs5030045.
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Diffusers and the floor ahead of them create the majority of the downforce a vehicle creates. Outside motorsports, the diffuser is relatively unused, although its interaction with the ground is a consistent field of study owing to the aerodynamic benefits. The diffuser flow behavior is governed by three fluid-mechanical mechanisms: ground interaction, underbody upsweep, and diffuser upsweep. In addition, four different flow regimes appear when varying ride height, the vortices of which have great importance on downforce generation. The present study focuses on the diffuser’s fluid-dynamic characteristics undertaken within an academic framework with the objective of finding and understanding a high level of performance in these elements. Once the functioning of diffusers has been analyzed and understood, a new configuration is proposed: rear vertical airfoil endplates. The aim of the paper is to study the effect in performance of vertical airfoil endplates on diffusers in vehicle aerodynamics in a simplified geometry. The candidate to this geometry is the inversed Ahmed body, a geometry that is used as a model that simulates the flow behavior of car diffusers. Three different diffuser configurations are performed, namely 0° diffuser, 25° diffuser, and in the third case vertically installed rear vertical airfoil endplates are added to the 25° diffuser Ahmed body to change the flow field. These analyses are carried out by using open-source CFD simulation software OpenFOAM. An inlet velocity of 20 m/s is considered, as this is a typical velocity when cornering in motorsport. It is concluded that the 25° diffuser configuration generated more downforce than the 0° diffuser, which makes sense as the aim of adding a diffuser is to increase the amount of downforce produced. In addition, and as a result of the newly proposed configuration, the 25° diffuser Ahmed body with the vertical airfoil endplates emerges in a substantial increase of downforce thanks to the low-pressure zone generated at the back of the body.
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KAMIARAISO, Haruka, Takuma KATO, Hayato GO, and Yuta SASAKI. "Downforce of wing yawing in ground effect." Proceedings of Conference of Kanto Branch 2019.25 (2019): 19H10. http://dx.doi.org/10.1299/jsmekanto.2019.25.19h10.
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YAMADA, Takao, Kosuke TANAKA, and Jian Ming YANG. "Development of Wall Mobile Robot by Downforce." Proceedings of Conference of Tokai Branch 2018.67 (2018): 625. http://dx.doi.org/10.1299/jsmetokai.2018.67.625.
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Szudarek, Maciej, and Janusz Piechna. "CFD Analysis of the Influence of the Front Wing Setup on a Time Attack Sports Car’s Aerodynamics." Energies 14, no. 23 (November 25, 2021): 7907. http://dx.doi.org/10.3390/en14237907.
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In time attack races, aerodynamics plays a vital role in achieving short track times. These races are characterized by frequent braking and acceleration supported by aerodynamic downforce. Usually, typical cars are modified for these races by amateurs. Adjusting the aerodynamic solutions to work with bodies developed for other flow conditions is difficult. This paper presents the results of a numerical analysis of the effects of installing a straight wing in front of or above the body on the modified vehicle system’s aerodynamic characteristics, particularly on the front wheels’ aerodynamic downforce values. The paper presents the methodology and results of calculations of the aerodynamic characteristics of a car with an additional wing placed in various positions in relation to the body. The numerical results are presented (Cd, Cl, Cm, Clf, Clr), as well as exemplary pressure distributions, pathlines, and visualizations of vortex structures. Strong interactions between the wing operation and body streamline structure are shown. An interesting and unexpected result of the analysis is that the possibility of obtaining aerodynamic downforce of the front wheels is identified, without an increase in aerodynamic drag, by means of a wing placed in a proper position in front of the body. A successful attempt to balance the additional downforce coming from the front wing on the front axle is made using a larger spoiler. However, for large angles of attack, periodically unsteady flow is captured with frequency oscillations of ca. 6–12 Hz at a car speed of 40 m/s, which may interfere with the sports car’s natural suspension frequency.
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Wang, Guo Xin, Yinuo Hu, Ting Ting Xu, Ze Fei Li, and Bo Yang. "Numerical Simulation and Wind Tunnel Experiment of the Aerodynamic Characteristics of a Formula Student Racing Car." Advanced Materials Research 774-776 (September 2013): 460–64. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.460.
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This research used CFD softwares to simulate the downforce generated with the airfoil set to different height, and also analyzed the difference on the downforce when the airfoil is set on the racing car. Several pairs of front wing (FW) and rear wing (RW) of different ground clearances were chosen during the wind tunnel experiment and the results were compared with those of the numerical simulations. With the results of the simulations as well as the experiment, an appropriate solution of the ground clearances of the FW and RW for different kinds of race is provided.
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Szudarek, Maciej, Konrad Kamieniecki, Sylwester Tudruj, and Janusz Piechna. "Towards Balanced Aerodynamic Axle Loading of a Car with Covered Wheels—Inflatable Splitter." Energies 15, no. 15 (July 30, 2022): 5543. http://dx.doi.org/10.3390/en15155543.
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Generating aerodynamic downforce for the wheels on the front axle of a car is a much more difficult task than for the rear axle. This paper, submitted to the special issue of Energies “Future of Road Vehicle Aerodynamics”, presents an unusual solution to increase the aerodynamic downforce of the front axle for cars with covered wheels, with the use of an elastic splitter. The effect of the inflatable splitter on the aerodynamic forces and moments was studied in a DrivAer passenger car and a fast sports car, Arrinera Hussarya. Providing that the ground clearance was low enough, the proposed solution was successful in increasing the front axle downforce without a significant increase in drag force. The possibility of emergency application of such a splitter in the configuration of the body rotated by up to 2 degrees with the front end raised was also analyzed. An elastic, deformed splitter remained effective for the nonzero pitch case. The results of the calculations are presented in the form of numerical data of aerodynamic forces, pressure and velocity distributions, and their comparisons. The benefits of the elastic splitter are documented, and the noted disadvantages are discussed.
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Shinde, Yash. "Dimples Effects on a Spoilers Aerodynamics." International Journal for Research in Applied Science and Engineering Technology 9, no. 8 (August 31, 2021): 1851–68. http://dx.doi.org/10.22214/ijraset.2021.37674.
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Abstract: Over the evolution of automobiles, performance, mileage, and grip have dramatically improved. Nevertheless, there have been some improvements, but now the ideal design has been reached for design of engine, airflow & tires, & ergonomics. This means that even very small design improvements could result in high performance enhancements. As fuel is becoming more expensive, the need for improved aerodynamics is becoming more acute. Thus, the purpose of this paper is to examine the effect of golf-like dimples on the aerodynamic properties of a spoiler. As such, numerical calculations and computational fluid dynamics calculations were performed to investigate the impact on aerodynamics and turbulence spoilers with various surface roughness and angle of attack. Based on the recorded data, this test will provide the best information on the appropriate size for the dimple. The data collected on the test model will be used to calculate the drag coefficient, the downforce, and the wake produced at 56 m/s speed, at four different attack angles. Different sizes & depths of dimples will be used to improve the aerodynamics of spoilers, which will improve their downforce, drag force and wake formation. Keywords: spoiler, aerodynamics, dimples, downforce, aerodynamic forces
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P. Nimje and R. Kakde. "Studying Forces on Three Different Designs of Formula 1 Front Wing." ARAI Journal of Mobility Technology 2, no. 4 (November 19, 2022): 332–65. http://dx.doi.org/10.37285/ajmt.2.4.2.
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A simulation-based study of three different types of front wing designs used in the modern Formula 1 cars was done. The study mainly focuses on the aerodynamic forces that a Formula One car generates mainly the Downforce, the Drag force, & the Lateral force. These forces were studied in detail & taken a closer look at how do they migrate during the dynamic conditions the car is thrown into namely at various Ride Height changes, at various Side Slip (Yaw) Angles. A further elaborative study of the force builds up across the span of the wing was studied giving us a better picture of the concentration of the Downforce, drag force, & Lateral force being generated which will help us to correlate the pressure distribution data across the wingspan to the actual downforce concentration figures. A brief study of the flow field & flow lines was conducted along with the vortex generation for all three wings. A short comparison was made between the modern wing & a wing Ferrari used in the 1998 season, which will help us to understand the inherent problems that those designs had & how modern wings get around those.
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Katz, J., and R. Largman. "Experimental Study of the Aerodynamic Interaction Between an Enclosed-Wheel Racing-Car and Its Rear Wing." Journal of Fluids Engineering 111, no. 2 (June 1, 1989): 154–59. http://dx.doi.org/10.1115/1.3243616.
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A quarter-scale model of an enclosed wheel racing car was tested using the elevated ground plane wind tunnel technique. To increase the aerodynamic down force, two longitudinal underbody channels were built into the vehicle’s lower surface, and a rear wing was added. The effect of these underbody channels, and of wing angle of attack and position, on the vehicle’s drag and down force was experimentally investigated. Results of the experiments indicate that the flow under the car is affected by the presence of the wheels, and the vehicle without a rear wing generates only a negligible downforce. However, the addition of a rear wing enhanced the flow under the vehicle body, resulting in an increased aerodynamic downforce.
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LEE and KIM. "Numerical Study of Active Aerodynamic Control via Flow Discharge on a High-Camber Rear Spoiler of a Road Vehicle." Applied Sciences 9, no. 22 (November 8, 2019): 4783. http://dx.doi.org/10.3390/app9224783.
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In this study, a numerical investigation of the active aerodynamic control via flow discharge was performed on a two-dimensional simplified vehicle with a spoiler. The analysis was performed using computational fluid dynamics techniques based on the unsteady Reynolds averaged Navier–Stokes equations. Unlike the conventional aerodynamic control methods, in which the control flow is forcibly injected to increase the lift or reduce the drag, the flow discharge method uses the ram air flow to reduce both the downforce and aerodynamic drag of a road vehicle. The technique of aerodynamic control via the flow discharge is applied to a simplified vehicle with a rear spoiler. For the isolated spoiler, at a discharge speed of 40% of the vehicle driving speed, the flow discharge at 75% of the chord exhibited a reduction of 4.5% and 1.8% in the aerodynamic drag and downforce reduction, respectively. For the vehicle with a spoiler, the drag and downforce were respectively reduced, on average, by 3.4% and 19.3% for a vehicle velocity range of 100–300 km/h; in this case, the discharge speed was 40% of the vehicle driving speed, and the discharge position was 75% of the chord owing to the interaction between the spoiler separation flow and vehicle wake.
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Marchesin, Felipe Pereira, Roberto Spinola Barbosa, Marco Gadola, and Daniel Chindamo. "High downforce race car vertical dynamics: aerodynamic index." Vehicle System Dynamics 56, no. 8 (December 14, 2017): 1269–88. http://dx.doi.org/10.1080/00423114.2017.1413196.
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O’Driscoll, Thomas P., and Andrew R. Barron. "CFD Analysis of the Location of a Rear Wing on an Aston Martin DB7 in Order to Optimize Aerodynamics for Motorsports." Vehicles 4, no. 2 (June 13, 2022): 608–20. http://dx.doi.org/10.3390/vehicles4020035.
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The purpose of this study is to identify the initial lateral and vertical location and angle of attack of a GT4-style rear wing on the rear downforce for an Aston Martin DB7 Vantage, prior to installation. The tests were completed with a two-dimensional model, using the Computational Fluid Dynamics (CFD) software, Fluent Ansys. The tests were completed using a range of velocities: 60–80 mph. Optimization of the position of the rear wing aerodynamic device was permitted under the Motorsport UK rules for multiple race series. The results show that while the drag decreases the farther back the wing is located, the desired configuration for the rear wing with regard to downforce is when it is positioned ca. 1850 mm back from the center point of the car, with an attack angle of 5°. Unusually, this is to the front of the boot/rear deck, but it is remarkably similar to where Aston Martin set the rear wing on their Le Mans car in 1995, above where the rear windscreen met the boot hinge, which was based upon wind tunnel studies using a scale model. Our results suggest that while 2D simulations of these types cannot give absolute values for downforce due to aerodynamic device location, they can provide low costs, fast simulation time, and a route for a wide range of cars, making the approach accessible to club motorsports, unlike complex 3D simulation and wind tunnel experimentation.
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Kim, S. C., and S. Y. Han. "Effect of steady airflow field on drag and downforce." International Journal of Automotive Technology 17, no. 2 (April 2016): 205–11. http://dx.doi.org/10.1007/s12239-016-0020-2.
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Metar, Manas. "Aerodynamic Analysis of Spoiler at Varying Speeds and Angles." International Journal for Research in Applied Science and Engineering Technology 9, no. 11 (November 30, 2021): 526–35. http://dx.doi.org/10.22214/ijraset.2021.38843.
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Abstract: Spoilers have been there in practice since years for the purpose of improving aerodynamics of a car. The pressure drag created at the end of the vehicle, referred to as wake region affects handling of the vehicle. This could be hazardous for the cars at high speeds. By adding a spoiler to the rear of the car reduces that pressure drag and the enhanced downforce helps in better traction. The paper presents aerodynamic analysis of a spoiler through Computational Fluid Dynamics analysis. The spoiler is designed using Onshape software and analyzed through SIMSCALE software. The simulation is carried out by changing angles of attack and velocities. The simulation results of downforce and drag are compared on the basis of analytical method. Keywords: Designing a spoiler, Design and analysis of spoiler, Aerodynamics of spoiler, Aerodynamic analysis of spoiler, Computational fluid dynamics, CFD analysis, CFD analysis of spoiler, Spoiler at variable angles, Types of spoilers, Analytical aerodynamic analysis.
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Guerrero, Alex, Robert Castilla, and Giorgio Eid. "A Numerical Aerodynamic Analysis on the Effect of Rear Underbody Diffusers on Road Cars." Applied Sciences 12, no. 8 (April 8, 2022): 3763. http://dx.doi.org/10.3390/app12083763.
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The aerodynamic complexity of the underbody surfaces of conventional road vehicles is a matter of fact. Currently available literature is focused mainly on very simple Ahmed-body geometries as opposed to realistic car shapes, due to their complexity and computational cost. We attempted to understand the flow behaviour around different realistic conventional road car geometries, and we provide an extensive evaluation of the aerodynamic loads generated. The key findings of this article could potentially set a precedent and be useful within the automotive industry’s investigations on drag-reduction mechanisms or sources of downforce generation. The novelty of the work resides in the realistic approach employed for the geometries and in the investigation of barely researched aerodynamic elements, such as front diffusers, which might pave the way for further research studies. A baseline flat-underfloor design, a 7∘ venturi diffuser-equipped setup, a venturi diffuser with diagonal skirts, and the same venturi diffuser with frontal slot-diffusers are the main configurations we studied. The numerical predictions evaluated using RANS computational fluid dynamics (CFD) simulations deal with the aerodynamic coefficients. The configuration that produced the highest downforce coefficient was the one composed of the 7∘ venturi diffuser equipped with diagonal sealing skirts, achieving a CL value of −0.887, which represents an increase of around 1780% with regard to the baseline model. That achievement and the gains in higher vertical loads also entail a compromise with an increase in the overall air resistance. The performance achieved with diffusers in the generation of downforce is, as opposed to the one obtained with conventional wings, a cleaner alternative, by avoiding wake disturbances and downwash phenomena.
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Vogt, Jonathan W., and Tracie J. Barber. "Ground effect phenomena about lift and downforce generating cambered aerofoils." International Journal of Numerical Methods for Heat & Fluid Flow 22, no. 2 (March 23, 2012): 153–74. http://dx.doi.org/10.1108/09615531211199809.
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., Asif Ahmed A. "CFD ANALYSIS OF DIFFUSER IN A CAR FOR DOWNFORCE GENERATION." International Journal of Research in Engineering and Technology 05, no. 07 (July 25, 2016): 158–64. http://dx.doi.org/10.15623/ijret.2016.0507026.
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Barber, T., and P. Kurts. "Downstream evolution of wingtip vortices produced from an inverted wing." Aeronautical Journal 119, no. 1216 (June 2015): 747–63. http://dx.doi.org/10.1017/s0001924000010800.
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AbstractCounter-rotating vortices form from the opposite edges of lifting surfaces, and gradually move laterally and dissipate as they travel downstream (as seen in a wing-fixed reference frame). Under ground effect conditions, the vortex from a lifting wing – such as that used in an aircraft application – moves laterally outboard from the wingtip as it progresses downstream; for a downforce wing in ground effect – such as that used in an automotive application – the vortex moves laterally inboard. An interesting case is the situation where the inboard moving vortices become in close proximity to each other. The objective of the present study was to investigate counter-rotating vortices produced from a low aspect ratio downforce wing operating in ground effect. The pair of vortices move towards each other and mutually induce an upwards directed motion which in turn reduces the inboard movement driven by the ground effect. Experimental data gained from three-dimensional Laser Doppler Anemometry in a moving ground wind-tunnel was used to validate a Large Eddy Simulation computational result.
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Szudarek, Maciej, Adam Piechna, and Janusz Piechna. "Feasibility Study of a Fan-Driven Device Generating Downforce for Road Cars." Energies 15, no. 15 (July 30, 2022): 5549. http://dx.doi.org/10.3390/en15155549.
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This paper, submitted to the special issue of Energies “Future of Road Vehicle Aerodynamics”, proposes and justifies the use of an old idea of generating downforce by actively drawing air from under the car body and exhausting it to the outside. Instead of traditional moving mechanical-curtain elements, a new method for sealing the clearance under the body with an air curtain is proposed. Basic information on the geometry and flow characteristics of such a solution suitable for use in automobiles is presented. The performance of such a fan-driven device generating downforce is studied over a wide range of driving speeds. The device allows for significantly improved vehicle acceleration, shorter braking distances, and extension of the range of safe cornering speeds. The paper shows the successive stages of development of the idea, from the 2D model to the 3D model, and an attempt to implement the device on a sports car. The distributions of pressure, velocity, pathlines and values of aerodynamic forces obtained at assumed fan compressions for different driving speeds are presented. The advantages and disadvantages of the analyzed device are discussed, and further optimization directions are outlined.
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Perez, Adolfo, and Armando Roman. "Morphing Air Foil NACA 6412 Inverted Using Flexure Hinges." Advanced Engineering Forum 45 (April 4, 2022): 43–48. http://dx.doi.org/10.4028/p-c8n56y.
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In this paper a NACA 6412 regulated shape will be inverted to understand the behaviour of the air flow around the shape, this with the intention of convert the lifting effect to a downforce and braking effect changing the shape of the wing, displacing the trailing edge approximately 100mm over the first stage position. Using analysis as Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) to depicts the operational parameters of the two stages of the inverted NACA 6412 air foil. To reach this displacement, the main idea is using a flexure hinge designed as a M-Shape beam, this flexure hinge works as a spring to allows to the morphing wing moves around the 100mm of trailing edge displacement and the spring-beam effect creates an inverse force, when the wing moves close to the110mm and does not exceed the yield strength of the Acrylonitrile butadiene styrene (ABS) of 74Mpa. As a result of this motion parameters, we could integrate a flexure hinge to an inverted air foil regulated to reach braking and downforce forces in order to slow down vehicles or aerodynamic devices.
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Diasinos, Sammy, Tracie Barber, and Graham Doig. "Numerical analysis of the effect of the change in the ride height on the aerodynamic front wing–wheel interactions of a racing car." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, no. 7 (April 11, 2017): 900–914. http://dx.doi.org/10.1177/0954407017700372.
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An investigation into the influence of the ground clearance on the aerodynamic interactions between the inverted front wing and the wheel of a racing car was conducted using computational fluid dynamics. Height-to-chord ratios h/ c from 0.075 to 0.27 were assessed for a single-element wing with a fixed angle of 4° and for two wing spans, one of which completely overlapped the wheel and the other which had its endplate coincident with the inside face of the wheel. With a narrower span, a lower peak downforce was achieved at a higher ground clearance owing to changes in the lower endplate vortex strength whereas, with a wider span, no downforce loss was observed, with decreasing clearance for those tested. This contrasted distinctly with the performance of the wing in isolation. The wheel lift was scarcely affected with decreasing wing ground clearance for the narrower span but decreased significantly for the wide-span wing at low ground clearances. The vortex paths changed considerably with the ground clearance, with a strong coupling to the wing span; a state in which the main vortex was destroyed in the contact patch of the wheel was identified.
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Janson, Tomasz, and Janusz Piechna. "Numerical Analysis of Aerodynamic Characteristics of a of High-Speed Car With Movable Bodywork Elements." Archive of Mechanical Engineering 62, no. 4 (December 1, 2015): 451–76. http://dx.doi.org/10.1515/meceng-2015-0026.
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Abstract This paper presents the results of numerical analysis of aerodynamic characteristics of a sports car equipped with movable aerodynamic elements. The effects of size, shape, position, angle of inclination of the moving flaps on the aerodynamic downforce and aerodynamic drag forces acting on the vehicle were investigated. The calculations were performed with the help of the ANSYS-Fluent CFD software. The transient flow of incompressible fluid around the car body with moving flaps, with modeled turbulence (model Spalart-Allmaras or SAS), was simulated. The paper presents examples of effective flap configuration, and the example of configuration which does not generate aerodynamic downforce. One compares the change in the forces generated at different angles of flap opening, pressure distribution, and visualization of streamlines around the body. There are shown the physical reasons for the observed abnormal characteristics of some flap configurations. The results of calculations are presented in the form of pressure contours, pathlines, and force changes in the function of the angle of flap rotation. There is also presented estimated practical suitability of particular flap configurations for controlling the high-speed car stability and performance.
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Broniszewski, Jakub, and Janusz Ryszard Piechna. "Fluid-Structure Interaction Analysis of a Competitive Car during Brake-in-Turn Manoeuvre." Energies 15, no. 8 (April 15, 2022): 2917. http://dx.doi.org/10.3390/en15082917.
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The relationship between the presented work and energy conservation is direct and indirect. Most of the literature related to energy-saving focuses on reducing the aerodynamic drag of cars, which typically leads to the appearance of vehicle motion instabilities at high speeds. Typically, this instability is compensated for by moving aerodynamic body components activated above a certain speed and left in that position until the vehicle speed drops. This change in vehicle configuration results in a significant increase in drag at high velocities. The presented study shows a fully coupled approach to fluid–structure interaction analyses of a car during a high-speed braking-in-turn manoeuvre. The results show how the aerodynamic configuration of a vehicle affects its dynamic behaviour. In this work, we used a novel approach, combining Computational Fluid Dynamics (CFD) analysis with the Multibody Dynamic System. The utilisation of an overset technique allows for car movement in the computational domain. Adding Moving Reference Frame (MRF) to this motion removes all restrictions regarding car trajectory and allows for velocity changes over time. We performed a comparative analysis for two aerodynamic configurations. In the first one, a stationary rear airfoil was in a base position parallel to a trunk generating low drag. No action of the driver was assumed. In the second scenario, brake activation initiates the rotation of the rear airfoil reaching in 0.1 s final position corresponding to maximum aerodynamic downforce generation. Also, no action of the driver was assumed. In the second scenario, the airfoil was moving from the base position up to the point when the whole system approached its maximum downforce. To determine this position, we ran a separated quasi-steady analysis in which the airfoil was rotating slowly to avoid transient effects. The obtained results show the importance of the downforce and load balance on car stability during break-in-turn manoeuvres. They also confirm that the proposed methodology of combining two independent solvers to analyse fluid–structure phenomena is efficient and robust. We captured the aerodynamic details caused by the car’s unsteady movement.
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Kurec, Krzysztof. "Numerical Study of the Sports Car Aerodynamic Enhancements." Energies 15, no. 18 (September 13, 2022): 6668. http://dx.doi.org/10.3390/en15186668.
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This study was prepared to demonstrate how the aerodynamics of a sports car can be enhanced, emphasizing aerodynamic improvements, and utilizing small movable elements. All the presented results were obtained using the numerical simulations performed in ANSYS Fluent in steady-state conditions. It was investigated how the performance of a car equipped with the splitter and the rear wing could be improved. The benefits of a top-mounted wing configuration were presented compared to a bottom-mounted setup. A change to the top-mounting configuration enabled undisturbed flow around the suction side of the wing and a more favorable placement of the wing to the car body. In the given case, an 80% increase of downforce was achieved in the performance mode of the car setup and a 16% increase of drag in the air braking mode. A method of the front splitter active steering was presented, which enabled a change of the generated downforce using only a small element that enabled an instant change of 30% without the necessity of moving the whole splitter plate. The described modifications of the sports car not only improved its aerodynamic properties but also enabled the means to accommodate it with an active aerodynamic system that would allow a quick adaptation to the current driving conditions.
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Schiele, Frank, and Bernd Gundelsweiler. "Design and Characterization of a Planar Motor Drive Platform Based on Piezoelectric Hemispherical Shell Resonators." Actuators 10, no. 8 (August 6, 2021): 187. http://dx.doi.org/10.3390/act10080187.
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In this study, a planar ultrasonic motor platform is presented that uses three half-side excited piezoelectric hemispherical shell resonators. To understand the working principle and the harmonic vibration behavior of the piezoelectric resonator, the trajectory of the friction contact was measured in free-oscillating mode at varying excitation frequencies and voltages. The driving performance of the platform was characterized with transport loads up to 5 kg that also serve as an influencing downforce for the friction motor. The working range for various transport loads and electrical voltages up to 30 V is presented. Undesirable noise and parasitic oscillations occur above the detected excitation voltage ranges, depending on the downforce. Therefore, minimum and maximum values of the excitation voltage are reported, in which the propulsion force and the speed of the planar motor can be adjusted, and noiseless motion applies. The multidimensional driving capacity of the platform is demonstrated in two orthogonal axes and one rotary axis in open-loop driving mode, by measuring forces and velocities to confirm its suitability as a planar motor concept. The maximum measured propulsion force of the motor was 7 N with a transport load of 5 kg, and its maximum measured velocity was 77 mm/s with a transport load of 3 kg.
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Akbar, Wazir, and Özgür Ertunç. "Model-Based Optimization of CMP Process Parameters for Uniform Material Removal Selectivity in Cu/Barrier Planarization." ECS Journal of Solid State Science and Technology 11, no. 2 (February 1, 2022): 024003. http://dx.doi.org/10.1149/2162-8777/ac4ffb.
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Chemical mechanical planarization is a process of achieving planar surfaces in the semiconductor manufacturing industry. The planarization of a surface is achieved by material removal from the wafer surface. The material removal depends on material properties and the process input parameters. Several studies have investigated the role of slurry chemistry to achieve a certain material removal selectivity of different materials on a patterned wafer. Here we propose a methodology of achieving planar patterned surface of Cu/Mn/MnN system using a model-based optimization for mechanical process parameters. The parameters include applied force, slurry solid concentration, and abrasive particle size. The methodology has been developed via optimization using a genetic algorithm. The proposed methodology suggests that a lower downforce is the key parameter to achieve the desired material removal selectivity and planarity. The first part of the study suggests a low material removal rate (MRR) to achieve a lower standard deviation in MRR. The second part investigates the standard deviation in the thickness removed in the average time needed to remove a known thickness of the materials under consideration. It has been found that the application of lower downforce can also minimize the standard deviation in the thickness removed and a planar patterned surface can be achieved.