Optimizing Dynamic Performance of High-Speed Road Vehicles Using Aerodynamic Aids

2016 ◽  
Author(s):  
Tushita Sikder ◽  
Saurabh Kapoor ◽  
Yuping He
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Lateral Stability ◽  
Road Vehicles ◽  
Ansys Fluent ◽  
The Road ◽  
High Speeds ◽  
Air Stream ◽  
High Dependency ◽  
Drag And Lift

This paper focuses on the effects of aerodynamic aids on the lateral and longitudinal dynamics of high-speed road vehicles. Aerodynamic aids, such as spoilers, can reduce drag to improve vehicle’s fuel economy and acceleration performance. On the other hand, aerodynamic aids can be utilized to enhance the lateral stability of the vehicle at high speeds by generating downforce or negative lift. However, the co-existence of drag and lift creates a paradox, that is, the downforce generated to improve car’s high-speed stability acts as a parasitic force on the car-body and slows down the vehicle forward speed. This paper will illustrate the juxtaposed effects of the aerodynamic forces on the lateral stability of the vehicle. Airfoils in the role of external aerodynamic aids will be examined based on their shapes, geometrical configurations, and at varying relative positions using the CFD technique. Moreover, the effects of attack angles, change in Reynold’s numbers (air stream velocities), and varying ground clearance on the lateral dynamics of the vehicle will be analyzed using numerical simulations with ANSYS FLUENT software package. The results and reliability of CFD simulations has a high dependency on the size of the grid, thus the aim of this paper will be to ensure that the results are independent of the grid size. Selection of the optimum design will be based on performance parameters like drag and lift coefficients. The challenge posed here is to ensure the lateral stability of the vehicle while achieving high average speed. Therefore, the main goal of the study is to enhance handling capabilities of the road vehicles at high speeds while minimizing the drag.

scholarly journals Suspending force modeling based on nonlinear acoustics and high-speed running experiments for an ultrasonic journal bearing

2020 ◽  
Vol 12 (7) ◽  
pp. 168781402094047
Author(s):  
He Li ◽  
Yu Wang ◽  
Deen Bai ◽  
Fuyan Lyu ◽  
Kuidong Gao ◽  
...  
Keyword(s):  
Lead Zirconate Titanate ◽  
Smart Materials ◽  
High Speed ◽  
Acoustic Radiation ◽  
Dynamic Performance ◽  
Force Model ◽  
Trajectory Data ◽  
Running Performance ◽  
High Speeds ◽  
Radiation Theory

As a kind of promising noncontact bearings, ultrasonic bearings actuated by smart materials such as lead zirconate titanate ceramics show a good application prospect in high-speed machines and precision-measuring devices. The suspending force is one of the most important parameters that play a dominated role on the bearing’s static and dynamic performance. A suspending force model based on acoustic radiation theory for cylindrical object near sound source is built to predict the radial carrying capacity of an ultrasonic bearing actuated by three piezoelectric transducers. To validate the model, an ultrasonic bearing prototype is developed and a testing system is established. For observing the bearing’s dynamic running performance at high speeds, the bearing’s running experiment is carried out and the rotor center’s trajectory data and frequency spectrum are acquired to analyze the bearing’s dynamic characteristics at high speeds. The suspending force model and running performance experiments will contribute to the design, detection, and test of this type of bearings.

An Integrated Approach to the Design and Analysis of an Ultra-High Speed Air-Bearing Spindle

2012 ◽  
Vol 723 ◽  
pp. 227-232 ◽  
Author(s):  
Si Yu Gao ◽  
Hui Ding ◽  
Kai Cheng
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Integrated Approach ◽  
System Optimization ◽  
Air Bearing ◽  
Design Environment ◽  
Virtual Design ◽  
High Speeds ◽  
Ultra High Speed ◽  
Structural Behaviors

This paper presents an integrated approach to the design and analysis of an ultra-high speed air bearing spindle, by integrating the structural design, performance analysis and system optimization in a virtual design environment. Firstly, the ultra-high speed air bearing spindle is designed, including grooved hybrid air bearing, helical water cooling channel and built-in motor, etc; Subsequently, pneumatic hammer instability and whirl instability of air bearing are studied; The thermal-structural behaviors of the spindle system at ultra-high speeds are investigated by using structural FEA coupled CFD; Static and dynamic performance of spindle is studied to predict the stiffness, modes and natural frequencies of the spindle; Lastly, system optimizations are conducted to obtain optimal performance and dynamic behaviors of the spindle. The proposed integrated approach can be used to design an optimal ultra-high speed air bearing spindle.

scholarly journals Investigation of Drag and Lift Forces over the Profile of Car with Rearspoiler using CFD

2015 ◽  
Vol 1 (8) ◽  
pp. 331
Author(s):  
Naveen Kumar Velagapudi ◽  
Lalit Narayan K. ◽  
L. N. V. Narasimha Rao ◽  
Sri Ram Y.
Keyword(s):  
Drag Force ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Fuel Utilization ◽  
Ansys Fluent ◽  
Total Drag ◽  
Rear Spoiler ◽  
Computational Fluid Dynamics Cfd ◽  
Lift Forces ◽  
Drag And Lift

Now a days demand of a high speed car is increasing in which vehicle stability is of major concern. Forces like drag& lift,weight,side forces and thrust acts on a vehicle when moving on road which significantly effect the fuel consumption The drag force is produced by relative motion between air and vehicle and about 60% of total drag is produced at the rear end. Reduction of drag force at the rear end improves the fuel utilization. This work aims to reduce the drag force which improves fuel utilization and protects environment as well. In the stage of work a sedan car with different types of spoilers are used to reduce the aerodynamic drag force. The design of sedan car has been done on CATIA-2010 and the same is used for analysis in ANSYS-(fluent). The analysis is done for finding out drag and lift forces at different velocities, and spoilers. This study proposes an effective numerical model based on the computational fluid dynamics (CFD) approach to obtain the flow structure around a passenger car with a rear spoiler

Dynamic Synthesis of Cams Using Finite Trigonometric Series

1975 ◽  
Vol 97 (1) ◽  
pp. 287-293 ◽  
Author(s):  
J. L. Wiederrich ◽  
B. Roth
Keyword(s):  
Mathematical Model ◽  
Trigonometric Series ◽  
High Speed ◽  
Dynamic Performance ◽  
Design Rules ◽  
New Methods ◽  
Dynamic Synthesis ◽  
High Speeds ◽  
Rules Of Thumb ◽  
Empirical Design

New methods are presented for the design of high-speed cam profiles. These methods have the advantage of assuring the accuracy of the assumed mathematical model while at the same time providing for good dynamic performance. These methods do not rely on rules of thumb. In fact, it is shown that at high speeds low vibration motions exist which violate heretofore commonly accepted empirical design rules.

scholarly journals Pemberdayaan Lintas Sektoral dalam upaya Mewujudkan Masyarakat Peduli Kesehatan dan Keselamatan Berkendara

2019 ◽  
Vol 4 (4) ◽  
pp. 443-450
Author(s):  
Nina Dwi Lestari ◽  
Arif Wahyu Setyo Budi ◽  
Al Afik
Keyword(s):  
Physical Environment ◽  
Traffic Accident ◽  
Traffic Accidents ◽  
Community Education ◽  
Health And Safety ◽  
Family Counseling ◽  
Road Accidents ◽  
Road Vehicles ◽  
The Road ◽  
High Speeds

CROSS SECTORAL EMPOWERMENT IN AN EFFORT TO REALIZE A COMMUNITY THAT CARES ABOUT HEALTH AND SAFETY DRIVING. Traffic accidents are a global phenomenon with increasing events that can result in losses and deaths. The most dominant human factor is related to traffic accident between vehicle and physical environment. WHO reports that around 1.2 million people die each year from road accidents and are a leading cause of death among young people aged 15-29 years. Partners in this program are residents of Rt 24, RW 12, Tegowanu, Kaliagung, Sentolo, Kulon Progo. The problems faced by partners are the high driving accidents in the partner area, due to geographical conditions of the road, vehicles that pass at high speeds from both directions, and poor driving behavior. The methods used in this program are community education, demonstrations, case simulations and family counseling. The result of this program are that there is an increase in partner’s knowledge related to driving health and safety, as much as 80% of participants are able to re-evacuate the techniques of evacuation, transportation and first aid in an accident at the location. It requires the efforts of the relevant parties to continue to accustom the culture of healthy and safety driving.

An Efficient Finite Element Procedure for Analysis of High-Speed Spiral Groove Gas Face Seals

2000 ◽  
Vol 123 (1) ◽  
pp. 205-210 ◽  
Author(s):  
Marco Tulio C. Faria
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Dynamic Performance ◽  
Dynamic Force ◽  
Spiral Groove ◽  
Weighted Residual Method ◽  
New Class ◽  
High Speeds ◽  
Face Seals ◽  
Finite Element Procedure

An efficient and accurate finite element procedure is specially devised to analyze the performance of gas-lubricated spiral groove face seals operating at high speeds. The procedure is based on the Galerkin weighted residual method with a new class of high-order shape functions, which are derived from an approximate solution to the nonlinear Reynolds equation within an element. Static and dynamic performance characteristics, such as seal opening force, flow leakage and frequency-dependent dynamic force coefficients, are determined to study the effects of high speeds on the behavior of spiral groove gas face seals.

Design of Tail Pipes for Jet Engines-Including Reheat

1950 ◽  
Vol 54 (472) ◽  
pp. 217-234
Author(s):  
John L. Edwards
Keyword(s):  
High Speed ◽  
Heat Energy ◽  
Forward Speed ◽  
Jet Engines ◽  
Entry And Exit ◽  
High Speeds ◽  
Heated Air ◽  
Air Stream ◽  
The Difference ◽  
Very High

The principle of the ram-jet or athodyd has been understood for a number of years. It has been applied in many ways, the most prominent being the flying bomb and, rather less spectacularly, the ducted radiator. The principle is to. convert the velocity energy of a high speed air stream to pressure energy by means of a suitable duct, to apply heat energy to the compressed air, and then to expand this heated air in the form of a high velocity jet. The advantage of such a mechanism is an increase in thrust given by the product of the mass flow of air, and the difference in velocities between entry and exit; the disadvantages are, the necessity to project the duct at high forward speed before any thrust is obtained and, except at very high speeds indeed, the low thermal efficiency.

scholarly journals Influence of Road Camber on Motorcycle Stability

2008 ◽  
Vol 75 (6) ◽  
Author(s):  
Simos Evangelou ◽  
David J. N. Limebeer ◽  
Maria Tomas Rodriguez
Keyword(s):  
High Speed ◽  
Road Vehicles ◽  
Adaptive Controllers ◽  
The Road ◽  
Tire Force ◽  
Wheeled Vehicle ◽  
Road Surfaces ◽  
The Stability ◽  
Induced Changes ◽  
Local Road

This paper studies the influence of road camber on the stability of single-track road vehicles. Road camber changes the magnitude and direction of the tire force and moment vectors relative to the wheels, as well as the combined-force limit one might obtain from the road tires. Camber-induced changes in the tire force and moment systems have knock-on consequences for the vehicle’s stability. The study makes use of computer simulations that exploit a high-fidelity motorcycle model whose parameter set is based on a Suzuki GSX-R1000 sports machine. In order to study camber-induced stability trends for a range of machine speeds and roll angles, we study the machine dynamics as the vehicle travels over the surface of a right circular cone. Conical road surfaces allow the machine to operate at a constant steady-state speed, a constant roll angle, and a constant road camber angle. The local road-tire contact behavior is analyzed by approximating the cone surface by moving tangent planes located under the road wheels. There is novelty in the way in which adaptive controllers are used to center the vehicle’s trajectory on a cone, which has its apex at the origin of the inertial reference frame. The results show that at low speed both the weave- and wobble-mode stabilities are at a maximum when the machine is perpendicular to the road surface. This trend is reversed at high speed, since the weave- and wobble-mode dampings are minimized by running conditions in which the wheels are orthogonal to the road. As a result, positive camber, which is often introduced by road builders to aid drainage and enhance the friction limit of four-wheeled vehicle tires, might be detrimental to the stability of two-wheeled machines.

A COMPARATIVE STUDY OF CAM MOTIONS FOR HIGH-SPEED SEMI-RIGID FOLLOWER CAM SYSTEMS

1988 ◽  
Vol 12 (3) ◽  
pp. 121-128 ◽  
Author(s):  
P.S. GREWAL ◽  
W.R. NEWCOMBE
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Poor Performance ◽  
Performance Criteria ◽  
Vibrational Response ◽  
High Speeds ◽  
Speed Performance ◽  
Cam Profile ◽  
Torque Values ◽  
Profile Errors

A study is presented on the comparison of all the popular cam motions based on a refined dynamic model which takes into account the effects of cam profile errors and most of the important factors that influence the dynamic performance for a semi-rigid follower cam system. A stochastic model is developed to simulate the input signal resulting from the cam motion, including the deviations due to profile errors. The performance criteria comprise the vibrational response at the follower and the dynamic characteristics at the cam. It has been established that, at high speeds, it is not the vibrational behaviour, but the follower tendency to jump and the maximum contact force and cam torque values which determine the dynamic performance. The Modified-Sine, Simple Harmonic and 3-4-5 Polynomial motions have been shown to exhibit superior high speed performance compared to that of the popular Cycloidal and Modified Trapezoidal motions. Higher-order Polynomial motions give very poor performance at high speeds.

scholarly journals Theoretical and Experimental Analysis of Dynamic Characteristics for a Valve Train System

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6328
Author(s):  
Bo Hu ◽  
Yunzhe Li ◽  
Lairong Yin
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Industrial Applications ◽  
Valve Train ◽  
Dynamic Responses ◽  
Engine Vibration ◽  
High Speeds ◽  
Proposed Model ◽  
Gyroscopic Effects ◽  
Train System

The valve train is one of the main sources of engine vibration, and its dynamic performance is crucial for output power and fuel consumption. The flexibilities of slender bars and beams should be emphasised in the design of valve trains to develop high-power and high-speed engines with industrial applications. A flexible dynamic model of a valve train system is proposed. In the proposed model, the components, except the cam and gear bodies, are modelled as flexible bodies with multidirectional deformations. The gyroscopic effects of the camshaft, cams and gear discs are also considered to predict dynamic responses at high speeds accurately. Gear meshing, the friction of the cam–tappet pair, the centrifugal force of the cams and valve clearance are also considered. Experiments on housing vibration and pushrod stress are conducted to validate the proposed model. Results show that the proposed model can predict the dynamic stress of the flexible components well and predict the trend shown by the housing vibration. The proposed model shows that excessive cam rotation speed and valve clearance will cause intense bounce and jump phenomena. The proposed model can be an important reference for designing engine work speed, adjusting valve clearance and improving component durability.

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