scholarly journals CFD Analysis of the Influence of the Front Wing Setup on a Time Attack Sports Car’s Aerodynamics

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7907
Author(s):  
Maciej Szudarek ◽  
Janusz Piechna
Keyword(s):  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
Vital Role ◽  
Front Axle ◽  
The Body ◽  
Strong Interactions ◽  
Unexpected Result ◽  
Proper Position ◽  
Pressure Distributions ◽  
Front Wing

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.

scholarly journals Computer Simulation of Car Aerodynamic Properties

2017 ◽  
Vol 65 (5) ◽  
pp. 1505-1514 ◽  
Author(s):  
Ivan Janoško ◽  
Tomáš Polonec ◽  
Peter Kuchar ◽  
Pavel Máchal ◽  
Martin Zach
Keyword(s):  
Rear Axle ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
Front Axle ◽  
Simulation Software ◽  
The Body ◽  
Body Parts ◽  
Aerodynamic Properties ◽  
Before And After ◽  
The Impact

The paper presents an optimization of car aerodynamic properties using the simulation software STAR‑CCM+. For real simulation was used tested car Fiat 127 which was modified on the performance car. The basic objective of this work is using computer simulations to obtain knowledge about the impact of individual body parts on the results of aerodynamic drag, downforce or lift. Based on the results, bodywork modifications will be designed to improve the aerodynamic characteristics of the body, but would not disrupt the basic shape and appearance of the vehicle. The modifications will be again subjected to tests in simulation software. On the modified body was significantly reduced torque of the front axle, while increased of rear axle (cca 1250 N.m). This caused a significant stabilizing effect on the rear axle. The results of simulation tests before and after use bodywork modifications are processed in graphical and numerical form.

scholarly journals Numerical Analysis of Aerodynamic Characteristics of a of High-Speed Car With Movable Bodywork Elements

2015 ◽  
Vol 62 (4) ◽  
pp. 451-476 ◽  
Author(s):  
Tomasz Janson ◽  
Janusz Piechna
Keyword(s):  
Numerical Analysis ◽  
High Speed ◽  
Transient Flow ◽  
Aerodynamic Drag ◽  
Position Angle ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Ansys Fluent ◽  
Drag Forces ◽  
And Performance

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.

Numerical and Neural Study of the Turbulent Flow Around Sharp-Edged Bodies

2002 ◽  
Author(s):  
Ahmed F. Abdel Gawad
Keyword(s):  
Flow Field ◽  
Thermal Behavior ◽  
Turbulence Modeling ◽  
Unstructured Grids ◽  
Flow Direction ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Pressure Distributions ◽  
Special Concern ◽  
Artificial Neural Network Ann

The study is based on K-ε turbulence modeling using both structured and unstructured grids. The pressure distributions in the flow field and on the surfaces of the bodies are determined. Different parameters that affect the flow field such as Reynolds number, aspect ratio of the body, and flow direction are considered. Special concern is paid to the separations at the corners of the body and the circulations behind the body. The thermal behavior due to the flow field is also considered. Nusselt number on the heated surfaces of the body is examined. The thermal behavior of a given body is strongly dependent on its aerodynamic characteristics. Comparisons are made between the present results and the available experimental data. Artificial Neural Network (ANN) was used to predict the values of the drag coefficient. Many useful conclusions and suggestions were drawn from the study.

scholarly journals The Mechanism of Secretion and Metabolism of Gut-Derived 5-Hydroxytryptamine

2021 ◽  
Vol 22 (15) ◽  
pp. 7931
Author(s):  
Ning Liu ◽  
Shiqiang Sun ◽  
Pengjie Wang ◽  
Yanan Sun ◽  
Qingjuan Hu ◽  
...  
Keyword(s):  
Cell Metabolism ◽  
Circulatory System ◽  
Vital Role ◽  
The Body ◽  
Neuroendocrine Cells ◽  
Intestinal Lumen ◽  
Paracrine Signaling ◽  
Inflammatory Conditions ◽  
Epithelial Development ◽  
Ec Cells

Serotonin, also known as 5-hydroxytryptamine (5-HT), is a metabolite of tryptophan and is reported to modulate the development and neurogenesis of the enteric nervous system, gut motility, secretion, inflammation, sensation, and epithelial development. Approximately 95% of 5-HT in the body is synthesized and secreted by enterochromaffin (EC) cells, the most common type of neuroendocrine cells in the gastrointestinal (GI) tract, through sensing signals from the intestinal lumen and the circulatory system. Gut microbiota, nutrients, and hormones are the main factors that play a vital role in regulating 5-HT secretion by EC cells. Apart from being an important neurotransmitter and a paracrine signaling molecule in the gut, gut-derived 5-HT was also shown to exert other biological functions (in autism and depression) far beyond the gut. Moreover, studies conducted on the regulation of 5-HT in the immune system demonstrated that 5-HT exerts anti-inflammatory and proinflammatory effects on the gut by binding to different receptors under intestinal inflammatory conditions. Understanding the regulatory mechanisms through which 5-HT participates in cell metabolism and physiology can provide potential therapeutic strategies for treating intestinal diseases. Herein, we review recent evidence to recapitulate the mechanisms of synthesis, secretion, regulation, and biofunction of 5-HT to improve the nutrition and health of humans.

scholarly journals Kidney Inflammation, Injury and Regeneration 2020

2021 ◽  
Vol 22 (11) ◽  
pp. 5589
Author(s):  
Patrick C. Baer ◽  
Benjamin Koch ◽  
Helmut Geiger
Keyword(s):  
Vital Role ◽  
The Body ◽  
Physiological Functions

The kidneys play a vital role in the basic physiological functions of the body [...]

scholarly journals Age-Related, Sport-Specific Adaptions of the Shoulder Girdle in Elite Adolescent Tennis Players

2014 ◽  
Vol 49 (5) ◽  
pp. 647-653 ◽  
Author(s):  
Ann M. Cools ◽  
Tanneke Palmans ◽  
Fredrik R. Johansson
Keyword(s):  
Muscle Strength ◽  
Shoulder Girdle ◽  
Vital Role ◽  
The Body ◽  
Injury Incidence ◽  
Shoulder Injury ◽  
Serratus Anterior ◽  
Cross Sectional ◽  
Tennis Players ◽  
Age Related

Context Tennis requires repetitive overhead movements that can lead to upper extremity injury. The scapula and the shoulder play a vital role in injury-free playing. Scapular dysfunction and glenohumeral changes in strength and range of motion (ROM) have been associated with shoulder injury in the overhead athlete. Objective To compare scapular position and strength and shoulder ROM and strength between Swedish elite tennis players of 3 age categories (<14, 14–16, and >16 years). Design Cross-sectional study. Setting Tennis training sports facilities. Patients or Other Participants Fifty-nine adolescent Swedish elite tennis players (ages 10–20 years) selected based on their national ranking. Main Outcome Measure(s) We used a clinical screening protocol with a digital inclinometer and a handheld dynamometer to measure scapular upward rotation at several angles of arm elevation, isometric scapular muscle strength, glenohumeral ROM, and isometric rotator cuff strength. Results Players older than 16 years showed less scapular upward rotation on the dominant side at 90° and 180° (P < .05). Although all absolute scapular muscle strength values increased with age, there was no change in the body-weight–normalized strength of the middle (P = .9) and lower (P = .81) trapezius or serratus anterior (P = .17). Glenohumeral internal-rotation ROM and total ROM tended to decrease, but this finding was not statistically significant (P = .052 and P = .06, respectively). Whereas normalized internal-rotator strength increased from 14 to 16 years to older than 16 years (P = .009), normalized external-rotator and supraspinatus strength remained unchanged. Conclusions Age-related changes in shoulder and scapular strength and ROM were apparent in elite adolescent tennis players. Future authors should examine the association of these adaptations with performance data and injury incidence.

Іmprovement of driving-speed properties improvement of the method for selecting the parameters of the motor-transmission unit car

2021 ◽  
Vol 13 (1) ◽  
pp. 111-117
Author(s):  
Mikhail Podrigalo ◽  
◽  
Volodymyr Krasnokutskyi ◽  
Vitaliy Kashkanov ◽  
Olexander Tkachenko ◽  
...  
Keyword(s):  
Aerodynamic Drag ◽  
Dynamic Properties ◽  
Aerodynamic Characteristics ◽  
Gear Ratio ◽  
Design Stage ◽  
Transmission Unit ◽  
Air Resistance ◽  
Design Speed ◽  
Maximum Design ◽  
Engine Power

Aerodynamic characteristics have a major impact on the energy efficiency and traction and speed properties of the vehicle. In this article, based on previous studies of the aerodynamic characteristics of various car models, we propose an improved method for selecting engine and transmission parameters at the design stage. The aim of the study is to improve the dynamic properties of the car by improving the method of selecting the main parameters of the engine-transmission unit by refining the calculation of aerodynamic drag. To achieve it, the following tasks must be solved: to specify the method of selecting the maximum effective engine power; to specify a technique of definition of the maximum constructive speed of the car; to develop a technique for selecting gear ratios. The aerodynamic resistance to the movement of the vehicle is determined by the frontal coefficient of the specified resistance, the density of the air, the area of the frontal resistance and the speed of the vehicle. It is known from classical works on the aerodynamics of a car that in the range of vehicle speeds from 20 m / s to 80 m / s, taking the law of squares when assessing the force of air resistance, it is necessary to change the coefficient of frontal aerodynamic drag depending on the speed of the car. However, when carrying out calculations, this coefficient is taken constant, which leads to obtaining large values of the air resistance force at high speeds and lower at low speeds. There are two possible ways to improve the dynamic properties and energy efficiency of the car during its modernization (increasing the maximum design speed of the car by reducing the gear ratio in higher gear; reducing the maximum efficiency of the engine while maintaining the previous gear ratio in higher gear). As a result of the study, the method of selection (maximum effective engine power; maximum design speed of the car; gear ratios) at the design stage of the parameters of the motor-transmission unit of the car has been improved.

Investigating the citation advantage of author-pays charges model in computer science research: a case study of Elsevier and Springer

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tehmina Amjad ◽  
Mehwish Sabir ◽  
Azra Shamim ◽  
Masooma Amjad ◽  
Ali Daud
Keyword(s):  
Open Access ◽  
Computer Science ◽  
Science Research ◽  
Vital Role ◽  
The Body ◽  
Content Type ◽  
Body Of Knowledge ◽  
Computer Science Research ◽  
Science Domain ◽  
Citation Advantage

PurposeCitation is an important measure of quality, and it plays a vital role in evaluating scientific research. However, citation advantage varies from discipline to discipline, subject to subject and topic to topic. This study aims to compare the citation advantage of open access and toll access articles from four subfields of computer science.Design/methodology/approachThis research studies the articles published by two prestigious publishers: Springer and Elsevier in the author-pays charges model from 2011 to 2015. For experimentation, four sub-domains of computer science are selected including (a) artificial intelligence, (b) human–computer interaction, (c) computer vision and graphics, and (d) software engineering. The open-access and toll-based citation advantage is studied and analyzed at the micro level within the computer science domain by performing independent sample t-tests.FindingsThe results of the study highlight that open access articles have a higher citation advantage as compared to toll access articles across years and sub-domains. Further, an increase in open access articles has been observed from 2011 to 2015. The findings of the study show that the citation advantage of open access articles varies among different sub-domains of a subject. The study contributed to the body of knowledge by validating the positive movement toward open access articles in the field of computer science and its sub-domains. Further, this work added the success of the author-pays charges model in terms of citation advantage to the literature of open access.Originality/valueTo the best of the authors’ knowledge, this is the first study to examine the citation advantage of the author-pays charges model at a subject level (computer science) along with four sub-domains of computer science.

Influence of Engine Cabin Simplification on Aerodynamic Characteristics of Car

2014 ◽  
Vol 1042 ◽  
pp. 188-193 ◽  
Author(s):  
Xing Jun Hu ◽  
Jing Chang
Keyword(s):  
Numerical Simulation ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
Thin Plates ◽  
Average Thickness ◽  
Two Dimensional ◽  
Engine Cooling ◽  
Aerodynamic Drag Coefficient ◽  
Simulation Results ◽  
The Impact

In order to analyze the impact of engine cabin parts on aerodynamic characteristics, the related parts are divided into three categories except the engine cooling components: front thin plates (average thickness of 2mm), bottom-suspension and interior panels. The aerodynamic drag coefficient (Cd) were obtained upon the combination schemes consisting of the three types of parts by numerical simulation. Results show that Cd by simulation is closer to the test value gained by the wind tunnel experiment when front thin plates were simplified to the two-dimensional interface with zero thickness. The error is only 5.23%. Meanwhile this scheme reduces grid numbers, thus decreasing the calculating time. As the front thin plates can guide the flow, there is no difference on the Cd values gained from the model with or without bottom-suspension or interior panels when the engine cabin contains the front thin plates; while only both bottom-suspension and interior panels are removed, the Cd value can be reduced when the cabin doesn’t contain the front thin plates.

An Investigation of the Forces on Three Dimensional Bluff Bodies in Rough Wall Turbulent Boundary Layers

1977 ◽  
Vol 99 (3) ◽  
pp. 503-509 ◽  
Author(s):  
B. E. Lee ◽  
B. F. Soliman
Keyword(s):  
Three Dimensional ◽  
The Body ◽  
Bluff Bodies ◽  
Drag Forces ◽  
Pressure Distributions ◽  
Mean Pressure ◽  
Flow Phenomena ◽  
The Mean ◽  
Building Ventilation ◽  
Group Density

A study has been made of the influence of grouping parameters on the mean pressure distributions experienced by three dimensional bluff bodies immersed in a turbulent boundary layer. The range of variable parameters has included group density, group pattern and incident flow type and direction for a simple cuboid element form. The three flow regimes associated with increasing group density are reflected in both the mean drag forces acting on the body and their associated pressure distributions. A comparison of both pressure distributions and velocity profile parameters with established work on two dimensional bodies shows close agreement in identifying these flow regime changes. It is considered that the application of these results may enhance our understanding of some common flow phenomena, including turbulent flow over rough surfaces, building ventilation studies and environmental wind around buildings.

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